Engine Controls Self-Diagnostics - Gasoline: Diagnosis Dodge Cab & Chassis R2500

SELF-DIAGNOSTIC SYSTEM

Note. Diagnostic tests are written specifically for Chrysler's Diagnostic Readout Box (DRBIII®) scan tool. A generic scan tool may not be capable of performing all necessary test functions.

Note. Throughout this article, models with Calif. emissions may be referred to as Calif. or Calif. models. Vehicles from other states may be equipped with Calif. emissions. Models with Federal emissions may be referred to as Federal or Federal models. Check underhood label for application.

ON-BOARD DIAGNOSTICS

Note. Before performing any testing procedures, check for any related technical service bulletins.

Note. Malfunction Indicator Light (MIL) may also be referred to as CHECK ENGINE light.

MIL is located on instrument cluster, just below the tachometer and is displayed as an engine icon. When ignition is first turned on, MIL should come on and remain on for 2 seconds to verify bulb and circuit operation, and then go off. If MIL does not come on and remain on for 2 seconds and then go off when ignition is first turned on, check instrument cluster for diagnosis of MIL. See ANALOG INSTRUMENT PANELS - RAM PICKUP article in ACCESSORIES & EQUIPMENT.

The Powertrain Control Module (PCM) monitors several different engine control system circuits. If malfunction occurs which affects vehicle emissions, a Diagnostic Trouble Code (DTC) will be set in PCM and PCM enters limp-in mode. In limp-in mode, PCM substitutes values for failed component and provides continuous engine operation. When DTC is set in PCM, the PCM will turn on MIL and MIL will remain on steady. In some instances, the MIL is turned on when the failure exists and DTC was set. These instances are referred to as one trip DTC. In may instances, the emission system must fail more then once before the PCM will turn on the MIL. These are referred to as a 2-trip DTC. For additional information for trip definition, see TRIP DEFINITION . If problem exists which does not affect vehicle emissions, a DTC will be set in PCM but MIL will not be turned on. OBD-II related DTCs are entered in PCM according to individual priority. The DTC priority determines when MIL is turned on and DTC self-erasure. For additional information for DTC priority and DTC self-erasure, see DIAGNOSTIC TROUBLE CODE PRIORITY & SELF-ERASURE . Non-emission related DTCs have no priority in which they are entered in the PCM.

PCM may not store a DTC for a monitored circuit even though a malfunction has occurred. This may happen because one of the criteria for DTC has not been met. For example, assume criteria for DTC requires PCM to monitor a specified sensor output circuit only when engine operates between 750 RPM and 2000 RPM. If the sensor output circuit becomes shorted to ground when engine is operating at 2400 RPM, DTC will not be set, as short to ground occurred at 2400 RPM which exceeds the limit when PCM monitors the circuit.

If PCM detects active engine misfire severe enough to cause catalytic converter damage, MIL will flash to warn the driver of possible damage and DTC will be set.

The PCM will turn off MIL when malfunction is not detected during 3 consecutive trips on all applications except an engine misfire monitor or fuel system monitor. For additional information on engine misfire monitor and fuel system monitor, see MONITORED CIRCUITS . The PCM will turn off MIL when malfunction is not detected during 3 engine misfire or fuel system monitor tests. The PCM performs engine misfire or fuel system monitor tests when engine is operating within 375 RPM and within 10 percent of the load of operating condition at which first malfunction was detected.

DTCs may be retrieved for system diagnosis. See RETRIEVING DIAGNOSTIC TROUBLE CODES . System malfunctions are identified as either hard failures or intermittent failures. For additional information on hard failures or intermittent failures, see HARD FAILURES and INTERMITTENT FAILURES .

Diagnostic Trouble Code Priority & Self-Erasure

With OBD-II, different OBD-II related Diagnostic Trouble Codes (DTC) have different priorities according to regulations. The DTC priority determines when Malfunction Indicator Light (MIL) will be turned on and DTC is erased or cleared from Powertrain Control Module (PCM). DTCs having a high priority will overwrite the lower priority DTCs. DTC priorities and description are as listed

1. Priority "O" - This is a non-emission related DTC.
2. Priority "1" - One-trip failure of a 2-trip DTC for non-fuel system and non-misfire conditions.
3. Priority "2" - One-trip failure of a 2-trip DTC for fuel system rich or fuel system lean condition, or misfire condition.
4. Priority "3" - Second trip failure for non-fuel system or non-misfire condition, or a one-trip failure.
5. Priority "4" - Second trip failure for fuel system rich or fuel system lean and misfire condition, or a one-trip catalyst damaging misfire.

One-trip failures on a 2-trip DTC have low priority and 2-trip failures have higher priority. One and 2-trip failures for fuel system monitor and misfire monitor take precedence over non-fuel system and non-misfire failures. Non-emission related DTCs have no priority in which they are entered in the PCM.

After 3 good trips, PCM will turn off the MIL. Once MIL is turned off, trip counter is switched to a warm-up counter. PCM must not detect the recent malfunction during 40 warm-up cycles. A warm-up cycle is defined as the engine is started, an increase of 40°F in engine coolant temperature exists after engine is started and engine coolant temperature reaches at least 160°F (71°C). After 40 warm-up cycles with no malfunction, PCM will clear DTC from PCM. DTCs may be cleared from PCM using scan tool, but this will clear OBD-II monitor data such as counter information, warm-up cycles, trips and freeze frame data.

DIAGNOSTIC PROCEDURE

If no faults were found while performing basic diagnostic procedures, proceed with self-diagnostics. Always perform a visual inspection before attempting to diagnose engine control system problems. See VISUAL INSPECTION .

VISUAL INSPECTION

Most driveability problems in the engine control system result from faulty wiring, poor electrical connections, improper wire routing or leaking air and vacuum hose connections. Inspect all engine control system components, hoses, connectors and wiring for damage before proceeding with self-diagnostics. After completing visual inspection, retrieve diagnostic trouble codes. See RETRIEVING DIAGNOSTIC TROUBLE CODES .

RETRIEVING DIAGNOSTIC TROUBLE CODES

Note. Ensure battery is fully charged before retrieving Diagnostic Trouble Codes (DTC).

Scheme 102

1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. (Scheme 102) Turn ignition on. Using scan tool manufacturer's instructions, read and record DTC messages (DRB scan tool) or DTCs (generic scan tool) and freeze frame data.
2. If scan tool displays a NO RESPONSE message, perform appropriate system test. See COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - RAM PICKUP article in ACCESSORIES & EQUIPMENT. Repair as necessary. If scan tool does not power up, check for loose cable connections or bad cable. If cable connections or cable is defective, repair or replace components as necessary, then recheck for DTCs. If cable connections and cable are okay, go to next step.
3. Measure voltage between ground and terminal No. 16 (Pink wire) at DLC. see scheme 10 Voltage should be at least 11 volts. If voltage is as specified, go to next step. If voltage is not as specified, check fuse No. 12 (10-amp) in junction block. Junction block is located on end of driver's side of instrument panel, near door opening. If fuse is okay, check Pink wire between fuse No. 12 and DLC. See DATA LINK CONNECTORS article in WIRING DIAGRAMS.
4. Measure resistance between ground and terminals No. 4 (Black/Light Green) and No. 5 (Black/Tan wire) at DLC. If both resistance readings are less than 5 ohms, ground circuits are okay and it may be necessary to try another scan tool or cable. If any resistance reading is 5 ohms or more, repair open in Black/Light Green wire or Black/Tan wire. See GROUND DISTRIBUTION article in WIRING DIAGRAMS.
5. If scan tool displays an error message, (i.e., USER-REQUESTED COLD BOOT or USER-REQUESTED WARM BOOT), follow scan tool manufacturer's instructions. If scan tool displays a bus failure error message, this indicates a scan tool failure or a bus circuit failure. To diagnose and repair bus circuit failure, see COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - RAM PICKUP article in ACCESSORIES & EQUIPMENT.
6. If any DTCs are displayed, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. After repair is complete, clear DTCs from PCM memory and perform appropriate verification test. Verification tests are located at the end of the diagnostic tests. If no DTCs are displayed, go to one of the following: For starting or driveability problems, go to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom. For speed control problems and servicing information, refer to appropriate CRUISE CONTROL SYSTEMS article in ACCESSORIES & EQUIPMENT. For charging system problems, refer to appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. For transmission electronic controls system problems, refer to appropriate ELECTRONIC CONTROLS article in AUTOMATIC TRANSMISSIONS.

CLEARING DIAGNOSTIC TROUBLE CODES

Note. Clearing Diagnostic Trouble Codes (DTC) with a scan tool will also erase all OBD-II monitor data. This includes all counter information for warm-up cycles, trips and freeze frame data.

Connect scan tool to Data Link Connector (DLC). DLC is located below driver's side of instrument panel. (Scheme 102) Turn ignition on. Using screen prompts on scan tool, clear DTCs from Powertrain Control Module (PCM). DTCs may be cleared from PCM if PCM does not detect the recent malfunction during 40 warm-up cycles. For additional information, see DIAGNOSTIC TROUBLE CODE PRIORITY & SELF-ERASURE.

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DIAGNOSTIC TROUBLE CODE MESSAGES & CODES

DIAGNOSTIC TESTS

Note. Before diagnosing an engine performance problem, refer to SERVICE PRECAUTIONS under SELF-DIAGNOSTIC SYSTEM before proceeding.

Note. Before diagnosing an engine performance problem, refer to ON-BOARD DIAGNOSTICS under SELF-DIAGNOSTIC SYSTEM for diagnostic system functions, abilities and system diagnostic procedures.

Note. Self-diagnostic tests are written specifically for Chrysler's Diagnostic Readout Box (DRBIII®) scan tool. A generic scan tool may not be capable of performing all necessary test functions.

Note. Throughout this article, models with Calif. emissions may be referred to as Calif. or Calif. models. Vehicles from other states may be equipped with Calif. emissions. Models with Federal emissions may be referred to as Federal or Federal models. Check underhood label for application.

Note. Before performing any testing procedures, check for any related technical service bulletins.

Testing

1. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for 5 minutes. If voltage changes to about zero volts, go to next step. If voltage does not change to about zero volts, go to step 3.
2. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Check for any contaminates that may have damaged the 1/1 HO2S such as contaminated fuel, unapproved silicone, oil and coolant. Repair any problems that are found. If no problems are found, start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor 1/1 HO2S voltage while wiggling connectors and wiring harness from 1/1 HO2S to Powertrain Control Module (PCM). PCM is located in right rear corner of engine compartment. see scheme 2 See «1/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S14963252342001051800000) table. If voltage changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused voltage to change. If voltage does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set by paying special attention to the conditions during which 1/1 HO2S is monitored. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
3. Disconnect 1/1 HO2S connector. See «1/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S14963252342001051800000) table. Measure resistance between Dark Green/White and Brown/Violet wires at 1/1 HO2S connector (component side). If resistance is not 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T) with HO2S at 70°F (21°C), replace 1/1 HO2S. If resistance is 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T), 1/1 HO2S heater element is okay. Go to next step.
4. Measure voltage between ground and Dark Green/White wire at 1/1 HO2S harness connector. If voltage is more than 12 volts, go to next step. If voltage is 12 volts or less, repair open in 1/1 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay (Calif. emission vehicles with 3.9L, 5.2L or 5.9L light-duty) and 1/1 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
5. Disconnect Powertrain Control Module (PCM) connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/Violet wire between 1/1 HO2S harness connector and terminal No. 8 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Violet wire.
6. At this time, PCM is assumed to be defective. Replace PCM.

1/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST and monitor 1/2 HO2S voltage for 5 minutes. If voltage changes to about zero volts, go to next step. If voltage does not change to about zero volts, go to step 3.
2. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Check for any contaminates that may have damaged the 1/2 HO2S such as contaminated fuel, unapproved silicone, oil and coolant. Repair any problems that are found. If no problems are found, start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor 1/2 HO2S voltage while wiggling connectors and wiring harness from 1/2 HO2S to Powertrain Control Module (PCM). PCM is located in right rear corner of engine compartment. see scheme 2 1/2 HO2S is located on exhaust pipe behind catalytic converter. If voltage changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused voltage to change. If voltage does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set by paying special attention to the conditions during which 1/2 HO2S is monitored. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
3. Disconnect 1/2 HO2S connector. Measure resistance between Dark Green/White and Brown/White wires at 1/2 HO2S connector (component side). If resistance is not 4-5 ohms with HO2S at 70°F (21°C), replace 1/2 HO2S. If resistance is 4-5 ohms, 1/2 HO2S heater element is okay. Go to next step.
4. Measure voltage between ground and Dark Green/White wire at 1/2 HO2S harness connector. If voltage is more than 12 volts, go to next step. If voltage is 12 volts or less, repair open in 1/2 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay (Calif. emission vehicles with 3.9L, 5.2L or 5.9L light-duty) and 1/2 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
5. Disconnect Powertrain Control Module (PCM) connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between 1/2 HO2S harness connector and terminal No. 16 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/White wire.
6. Measure voltage between ground and terminal No. 16 (Brown/White wire) at PCM C3 harness connector. If no voltage is present, go to next step. If any voltage is present, repair short to voltage in Brown/White wire between 1/2 HO2S and PCM.
7. At this time, PCM is assumed to be defective. Replace PCM.

1. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for 5 minutes. If voltage changes to about zero volts, go to next step. If voltage does not change to about zero volts, go to step 3.
2. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Check for any contaminates that may have damaged the 2/1 HO2S such as contaminated fuel, unapproved silicone, oil and coolant. Repair any problems that are found. If no problems are found, start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor 2/1 HO2S voltage while wiggling connectors and wiring harness from 2/1 HO2S to Powertrain Control Module (PCM). PCM is located in right rear corner of engine compartment. see scheme 2 See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S15068824482001052100000) table. If voltage changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused voltage to change. If voltage does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set by paying special attention to the conditions during which 2/1 HO2S is monitored. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
3. Disconnect 2/1 HO2S connector. Measure resistance between Dark Green/White and Brown/White wires at 2/1 HO2S connector (component side). If resistance is not 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T) with HO2S at 70°F (21°C), replace 2/1 HO2S. If resistance is 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T), 2/1 HO2S heater element is okay. Go to next step.
4. Measure voltage between ground and Dark Green/White wire at 2/1 HO2S harness connector. If voltage is more than 12 volts, go to next step. If voltage is 12 volts or less, repair open in 2/1 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay (Calif. emission vehicles with 3.9L, 5.2L or 5.9L light-duty) and 2/1 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
5. Disconnect Powertrain Control Module (PCM) connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between 2/1 HO2S harness connector and terminal No. 16 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/White wire.
6. Measure voltage between ground and terminal No. 16 (Brown/White wire) at PCM C3 harness connector. If no voltage is present, go to next step. If any voltage is present, repair short to voltage in Brown/White wire between 2/1 HO2S and PCM.
7. At this time, PCM is assumed to be defective. Replace PCM.

2/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0071 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0071 or displayed count is not "0", go to step 6.
2. Turn ignition off. Disconnect BTS connector. BTS is located under battery and has a Black 2-pin connector. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, connect a jumper wire between BTS harness connector terminals. Turn ignition on. Using scan tool, read BTS voltage. If voltage is less than one volt, replace BTS. If voltage is one volt or more, go to next step.
3. Turn ignition off. Reconnect BTS connector. Locate PCM in right rear corner of engine compartment. see scheme 2 Using a voltmeter, backprobe Black/Light Blue wire between BTS harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21 Start engine and note voltage reading. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Light Blue wire.
4. Turn ignition off. Using a voltmeter, backprobe Pink/Yellow wire between BTS harness connector and terminal No. 15 at PCM C3 harness connector. see scheme 21 Start engine and note voltage reading. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Pink/Yellow wire.
5. At this time, PCM is assumed to be defective. Replace PCM.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read MAP sensor voltage. If voltage is less than 1.2 volts, go to next step. If voltage is 1.2 volts or more, go to step 4.
2. Start engine and allow it to idle. Using scan tool, read MAP sensor voltage. If voltage is less than.04 volt, go to step 4. If voltage is.04 volt or more, go to next step.
3. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
4. Turn ignition off. Disconnect MAP sensor connector. On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. (Scheme 103) On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. (Scheme 104) On all models, turn ignition on. Measure voltage between ground and Violet/White wire at MAP sensor harness connector. If voltage is 4.5-5.2 volts, go to next step. If voltage is not 4.5-5.2 volts, go to step 8.
5. Ensure ignition is on. Using scan tool, read MAP sensor voltage. If voltage is 1.2 volts or less, go to next step. If voltage is more than 1.2 volts, replace MAP sensor.
6. Turn ignition off. Ensure MAP sensor is disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Dark Green/Red wire at MAP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green/Red wire between PCM and MAP sensor.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. Turn ignition off. Ensure MAP sensor is disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Violet/White wire at MAP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/White wire between PCM and MAP sensor.
9. Measure resistance of Violet/White wire between MAP sensor harness connector and terminal No. 17 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire between MAP and PCM.
10. At this time, PCM is assumed to be defective. Replace PCM.

Scheme 103

Scheme 104

1. Start engine and allow engine to idle. Using scan tool, read MAP sensor voltage. If MAP sensor voltage is more than 4.6 volts, go to next step. If MAP sensor voltage 4.6 volts or less, go to step 8.
2. Turn ignition off. Disconnect MAP sensor connector. On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. (Scheme 103) On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. (Scheme 104) On all models, disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between Dark Green/Red and Violet/White wires at MAP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Dark Green/Red and Violet/White wires are shorted together. Repair wiring as necessary.
3. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and Dark Green/Red wire at MAP sensor harness connector. If voltage is 5.2 volts or less, go to next step. If voltage is more than 5.2 volts, repair short to voltage in Dark Green/Red wire.
4. Turn ignition off. Connect a jumper wire between Black/Light Blue and Dark Green/Red wires at MAP sensor harness connector. Turn ignition on. Using scan tool, read MAP sensor voltage. If voltage is one volt or more, go to next step. If voltage is less than one volt, replace MAP sensor.
5. Turn ignition off. Disconnect jumper wire. Disconnect PCM connectors. Measure resistance of Dark Green/Red wire between MAP sensor harness connector and terminal No. 27 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green/Red wire.
6. Measure resistance of Black/Light Blue wire between MAP sensor harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0111 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0111 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect IAT sensor connector. IAT sensor is located on intake manifold. (Scheme 105)or (Scheme 106). Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Using scan tool, read IAT sensor voltage. If voltage is more than 4.6 volts, go to next step. If voltage is 4.6 volts or less, go to step 4.
3. Turn ignition off. Connect a jumper wire between IAT sensor harness connector terminals. Turn ignition on. Using scan tool, read IAT sensor voltage. If voltage is one volt or more, go to next step. If voltage is less than one volt, replace IAT sensor.
4. Turn ignition off. Reconnect all connectors. Using a voltmeter, backprobe Black/Light Blue wire between terminal No. 1 IAT sensor harness connector and terminal A15 at PCM C1 harness connector. see scheme 19and see scheme 21. PCM is located in right rear corner of engine compartment. see scheme 2 If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Light Blue wire.
5. Turn ignition off. Using a voltmeter, backprobe Black/Red wire between terminal No. 2 at IAT harness connector and terminal No. 15 at PCM C1 harness connector. Start engine and note voltage reading. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Red wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor IAT sensor voltage while wiggling connectors and wiring harness from IAT sensor to PCM. IAT sensor is located on intake manifold. (Scheme 105)or (Scheme 106). PCM is located in right rear corner of engine compartment. see scheme 2 If voltage changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused voltage to change. If voltage does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set by paying special attention to the conditions during which IAT sensor is monitored. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, go to next step.

Scheme 105

Scheme 106

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0112 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0112 is not displayed or displayed count is not "0", go to step 8.
2. Ensure ignition is on. Using scan tool, read IAT sensor voltage. If voltage is less than one volt, go to step 4. If voltage is one volt or more, go to next step.
3. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, go to next step.
4. Turn ignition off. Disconnect IAT sensor connector. IAT sensor is located on intake manifold. (Scheme 105)or (Scheme 106). Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Using scan tool, read IAT sensor voltage. If voltage is one volt or less, go to next step. If voltage is more than one volt, replace IAT sensor.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and terminal No. 2 (Black/Red wire) at IAT sensor harness connector. see scheme 19 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Black/Red wire between PCM and IAT sensor.
6. Measure resistance between terminals No. 1 (Black/Light Blue wire) and No. 2 (Black/Red wire) at IAT sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Black/Light Blue and Black/Red wires are shorted together. Repair wiring as necessary.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0113 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0113 is not displayed or displayed count is not "0", go to step 4.
2. Using scan tool, read IAT sensor voltage. If voltage is more than 4.6 volts, go to next step. If voltage is 4.6 volts or less, go to step 4.
3. Turn ignition off. IAT sensor is located on intake manifold. (Scheme 105)or (Scheme 106). Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, start engine and allow it to idle. Measure voltage between ground and terminal No. 2 (Black/Red wire) at IAT sensor harness connector. see scheme 19 If voltage is 5.5 volts or less, go to next step. If voltage is more than 5.5 volts, repair short to voltage in Black/Red wire between IAT sensor and PCM.
4. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0117 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0117 is not displayed or displayed count is not "0", go to step 6.
2. Turn ignition off. Disconnect ECT sensor connector. ECT sensor is located near thermostat housing on intake manifold and contains Black/Light Blue and Tan/Black wires in the connector. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Using scan tool, read ECT sensor voltage. If voltage is one volt or less, go to next step. If voltage is more than one volt, replace ECT sensor.
3. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and terminal No. 2 (Tan/Black wire) at ECT sensor harness connector. see scheme 11 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Tan/Black wire between PCM and ECT sensor.
4. Measure resistance between terminals No. 1 (Black/Light Blue wire) and No. 2 (Tan/Black wire) at ECT sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Black/Light Blue and Tan/Black wires are shorted together. Repair wiring as necessary.
5. At this time, PCM is assumed to be defective. Replace PCM.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read ECT sensor voltage. If voltage is more than 4.6 volts, go to next step. If voltage is 4.6 volts or less, go to step 7.
2. Turn ignition off. Disconnect ECT sensor connector. ECT sensor is located near thermostat housing on intake manifold and contains Black/Light Blue wire and Tan/Black wire in the connector. Turn ignition on. Measure voltage between ground and terminal No. 2 (Tan/Black wire) at ECT sensor harness connector. see scheme 11 If voltage is 5.2 volts or less, go to next step. If voltage is more than 5.2 volts, repair short to voltage in Tan/Black wire.
3. Turn ignition off. Connect a jumper wire between terminals No. 1 (Black/Light Blue wire) and No. 2 (Tan/Black wire) at ECT sensor harness connector. Turn ignition on. Using scan tool, read ECT voltage. If voltage is one volt or more, go to next step. If voltage is less than one volt, replace ECT sensor.
4. Turn ignition off. Disconnect jumper wire. Ensure ECT sensor is disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Tan/Black wire between terminal No. 2 at ECT sensor harness connector and terminal No. 16 at PCM C1 harness connector. see scheme 11and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Tan/Black wire.
5. Measure resistance of Black/Light Blue wire between terminal No. 1 at ECT sensor harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

Note. If any TP sensor or MAP sensor related DTCs are also present, repair those DTCs before continuing with this test.

Scheme 107

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0121 is displayed and displayed count is "0", go to next step. If DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL is also present, go to «DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL»(ref-97638-S04161666782001051000000). If GOOD TRIP counter for DTC P0121 is not displayed or displayed count is not "0", go to step 22.
2. Start engine and allow it to idle. Using scan tool, monitor MAP sensor voltage and snap throttle open and closed. If voltage is less than 2 volts at idle and more than 3.5 volts at open throttle, turn ignition off and go to next step. If voltage is not less than 2 volts at idle and more than 3.5 volts at open throttle, go to step 13.
3. Turn ignition on. Using scan tool, monitor TP sensor voltage while slowly depressing throttle pedal from idle position to wide open throttle position. If voltage changes smoothly from about.8 volt to more than 3.5 volts, go to step 22. If voltage does not change smoothly from about.8 volt to more than 3.5 volts, go to next step.
4. Turn ignition off. Disconnect TP sensor connector. (Scheme 103)or (Scheme 107). Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Violet/White wire between terminal No. 1 at TP sensor harness connector and terminal No. 17 at PCM C1 harness connector. see scheme 21and see scheme 23. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire.
5. Measure resistance between ground and terminal No. 1 (Violet/White wire) at TP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/White wire between TP sensor and PCM.
6. Disconnect MAP sensor connector. On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. (Scheme 103) On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. (Scheme 104) On all models, measure resistance between ground and Dark Green/Red wire at MAP sensor harness connector. If resistance is more than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short to ground in Dark Green/Red wire between MAP sensor and PCM.
7. Measure resistance of Black/Light Blue wire between MAP sensor harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
8. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Using scan tool, read TP sensor voltage. Connect a jumper wire between terminals No. 2 (Orange/Dark Blue wire) and No. 3 (Black/Light Blue wire) at TP sensor harness connector. If TP sensor voltage changes from about 4.9 volts to less than.5 volt, replace TP sensor. If TP sensor voltage does not change from about 4.9 volts to less than.5 volt, go to next step.
9. Turn ignition off. Ensure TP sensor is disconnected. Disconnect PCM connectors. Measure resistance of Orange/Dark Blue wire between terminal No. 2 at TP sensor harness connector and terminal No. 23 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange/Dark Blue wire.
10. Measure resistance between ground and terminal No. 2 (Orange/Dark Blue wire) at TP sensor harness connector. If resistance is more than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short to ground in Orange/Dark Blue wire between PCM and TP sensor.
11. Measure resistance of Black/Light Blue wire between terminal No. 3 at TP sensor harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21and see scheme 23. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
12. At this time, PCM is assumed to be defective. Replace PCM.
13. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Disconnect MAP sensor connector. On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. (Scheme 103) On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. (Scheme 104) On all models, measure resistance of Violet/White wire between MAP sensor harness connector and terminal No. 17 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire.
14. Measure resistance between ground and Violet/White wire at MAP sensor harness connector. If resistance is more than 5 ohms, go to next step. If resistance is 5 ohms or less, repair short to ground in Violet/White wire.
15. Disconnect TP sensor connector. (Scheme 103)or (Scheme 107). Measure resistance of Violet/White wire between terminal No. 1 at TP sensor harness connector and terminal No. 17 PCM C1 harness connector. see scheme 21and see scheme 23. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire.
16. Measure resistance between ground and terminal No. 1 (Violet/White wire) at TP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/White wire between TP sensor and PCM.
17. Ensure ignition is off. Reconnect PCM connectors. Ensure MAP sensor is disconnected. Turn ignition on. Using scan tool, read MAP sensor voltage. Connect a jumper wire between Black/Light Blue and Dark Green/Red wires at MAP sensor harness connector. If MAP sensor voltage changes from about 4.9 volts to less than.5 volt, replace MAP sensor. If MAP sensor voltage does not change from about 4.9 volts to less than.5 volt, go to next step.
18. Turn ignition off. Disconnect PCM connectors. Measure resistance of Dark Green/Red wire between MAP sensor harness connector and terminal No. 27 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green/Red wire.
19. Measure resistance between ground and Dark Green/Red wire at MAP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green/Red wire.
20. Measure resistance of Black/Light Blue wire between MAP sensor harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
21. At this time, PCM is assumed to be defective. Replace PCM.
22. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read TP sensor voltage. If voltage is less than.2 volt, go to next step. If TP sensor voltage is.2 volt or more, go to step 11.
2. Turn ignition off. Disconnect TP sensor connector. (Scheme 103)or (Scheme 107). Turn ignition on. Measure voltage between ground and terminal No. 1 (Violet/White wire) at TP sensor harness connector. see scheme 23 If voltage is 4.5-5.2 volts, go to next step. If voltage is not 4.5-5.2 volts, go to step 8.
3. Using scan tool, read TP sensor voltage. If voltage is 4.5 volts or less, go to next step. If voltage is more than 4.5 volts, replace TP sensor.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 2 (Orange/Dark Blue wire) at TP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Orange/Dark Blue wire between PCM and TP sensor.
5. Ensure TP sensor connector and PCM connectors are still disconnected. Measure resistance between terminals No. 2 (Orange/Dark Blue wire) and No. 3 (Black/Light Blue wire) at TP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange/Dark Blue and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. Turn ignition off. Ensure TP sensor is disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 1 (Violet/White wire) at TP sensor harness connector. see scheme 23 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Violet/White wire between TP sensor and PCM.
8. Measure resistance of Violet/White wire between terminal No. 1 at TP sensor harness connector and terminal No. 17 PCM C1 harness connector. see scheme 21and see scheme 23. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire.
9. At this time, PCM is assumed to be defective. Replace PCM.
10. Turn ignition on. Using scan tool, monitor TP sensor voltage while slowly depressing throttle pedal from idle position to wide open throttle position. If voltage changes smoothly from about.8 volt to more than 3.5 volts, go to next step. If voltage does not change smoothly from about.8 volt to more than 3.5 volts, replace TP sensor.
11. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

Note. Ensure throttle plate is fully closed, no carbon build-up exists on throttle plate and throttle does not bind.

1. Start engine and allow it to idle. Using scan tool, read TP sensor voltage. If voltage is more than 4.5 volts, go to next step. If voltage is 4.5 volts or less, turn ignition off and go to step 9.
2. Turn ignition off. Disconnect TP sensor connector. (Scheme 103)or (Scheme 107). Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between terminals No. 1 (Violet/White wire) and No. 2 (Orange/Dark Blue wire) at TP sensor harness connector. see scheme 23 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Violet/White and Orange/Dark Blue wires are shorted together. Repair wiring as necessary.
3. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and terminal No. 2 (Orange/Dark Blue wire) at TP sensor harness connector. If voltage is 5.2 volts or less, go to next step. If voltage is more than 5.2 volts, repair short to voltage in Orange/Dark Blue wire.
4. Turn ignition off. Connect a jumper wire between terminals No. 2 (Orange/Dark Blue wire) and No. 3 (Black/Light Blue wire) at TP sensor harness connector. Using scan tool, read TP sensor voltage. Turn ignition on. If voltage is.5 volt or more, go to next step. If voltage is less than.5 volt, replace TP sensor.
5. Turn ignition off. Ensure TP sensor is disconnected. Disconnect PCM connectors. Measure resistance of Black/Light Blue wire between terminal No. 3 at TP sensor harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
6. Measure resistance of Orange/Dark Blue wire between terminal No. 2 at TP sensor harness connector and terminal No. 23 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange/Dark Blue wire.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. Turn ignition on. Using scan tool, monitor TP sensor voltage while slowly depressing throttle pedal from idle position to wide open throttle position. If voltage changes smoothly from about.8 volt to more than 3.5 volts, go to next step. If voltage does not change smoothly from about.8 volt to more than 3.5 volts, replace TP sensor.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

Note. To diagnose this DTC, manufacturer recommends allowing vehicle to sit overnight in order to have a totally cold engine. If any ECT sensor DTCs are present, repair those DTCs before continuing with this test. Extremely cold outside ambient temperatures may have caused this DTC to set.

1. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0125 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0125 is not displayed or displayed count is not "0", go to step 5.
2. Ensure coolant level is in good condition and at proper level. Replace or top off coolant as necessary. If coolant is okay, go to next step.
3. Turn ignition on. Using scan tool, read ENG COOLANT TPM DEG value. If engine was allowed to sit overnight, scan tool temperature value should be near ambient air temperature. If engine coolant temperature is more than 180°F (82°C), allow engine coolant temperature to cool down to 150°F (66°C) before proceeding. If engine coolant temperature is 150°F (65°C) or less, start engine. Using scan tool, monitor ENG COOLANT TPM DEG until engine coolant temperature reaches 180°F (82°C). Temperature value should increase smoothly from start-up to normal operating temperature. Also monitor actual coolant temperature with a thermometer. As engine warms up to normal operating temperature, actual coolant temperature should be relatively close to temperature reading on scan tool. Monitor coolant temperature and note when thermostat opens. Thermostat should open at about 195°F (90°C). Replace thermostat as necessary. If thermostat opens as specified, go to next step.
4. If coolant temperature increased smoothly, no problem is indicated at this time. Test is complete. If temperature did not increase smoothly, turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, go to next step.
5. Disconnect ECT sensor connector. ECT sensor is located near thermostat housing on intake manifold and contains Black/Light Blue and Tan/Black wires in the connector. Visually inspect connector for corroded, damaged, pushed-out or miswired terminals. Repair connector as necessary. If connector is okay, replace ECT sensor.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0131 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0131 is not displayed or displayed count is not "0", go to step 8.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 1/1 HO2S voltage. If voltage is less than.16 volt, go to next step. If voltage is.16 volt or more, go to step 8.
3. Turn ignition off. Disconnect 1/1 HO2S connector. See «1/1 OXYGEN SENSOR LOCATION»(ref-97638-S39564467952001051000000) table. Start engine and allow it to idle. Using scan tool, read 1/1 HO2S voltage. If voltage is.16 volt or less, go to next step. If voltage is more than.16 volt, replace 1/1 HO2S.
4. Turn ignition off. Ensure 1/1 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) at 1/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Black/Dark Green wire or Tan/White wire between PCM and 1/1 HO2S.
5. Measure resistance between Black/Light Blue wire and Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) at 1/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Black/Light Blue wire is shorted to Black/Dark Green wire or Tan/White wire. Repair wiring as necessary.
6. Measure resistance between Brown/Violet wire and Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) at 1/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Brown/Violet wire is shorted to Black/Dark Green wire or Tan/White wire. Repair wiring as necessary.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0132 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0132 is not displayed or displayed count is not "0", go to step 9.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 1/1 HO2S voltage. If voltage is more than 1.2 volts, go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Turn ignition off. Disconnect 1/1 HO2S connector. See «1/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S39564467952001051000000) table. Start engine and allow it to idle. Using scan tool, read 1/1 HO2S voltage. If voltage is 1.2 volts or more, go to next step. If voltage is less than 1.2 volts, replace 1/1 HO2S.
4. Turn ignition off. Ensure 1/1 HO2S is still disconnected. Turn ignition on. Measure voltage between ground and Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) at 1/1 HO2S harness connector. If voltage is 1.2 volts or less, go to next step. If voltage is more than 1.2 volts, repair short to voltage in Black/Dark Green wire or Tan/White wire between PCM and 1/1 HO2S.
5. Turn ignition off. Measure resistance between Dark Green/White wire and Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) at 1/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Dark Green/White wire is shorted to Black/Dark Green wire or Violet/Orange wire. Repair wiring as necessary.
6. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) between 1/1 HO2S harness connector and terminal No. 24 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Dark Green wire or Tan/White wire.
7. Measure resistance of Black/Light Blue wire between 1/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0133 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0133 or displayed count is not "0", go to step 6.
2. Start engine and allow it to idle. Check exhaust system for leaks between engine and 1/1 HO2S. See «1/1 OXYGEN SENSOR LOCATION»(ref-97638-S39564467952001051000000) table. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Ensure engine is still idling. Using voltmeter, backprobe Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) between 1/1 HO2S harness connector and terminal No. 24 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Dark Green wire or Tan/White wire between 1/1 HO2S and PCM.
4. Using voltmeter, backprobe Black/Light Blue wire between 1/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Light Blue wire between 1/1 HO2S and PCM.
5. At this time, 1/1 HO2S is assumed to be defective. Replace 1/1 HO2S.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0135 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0135 or displayed count is not "0", go to step 3.
2. Turn ignition off. Allow HO2S to cool down for at least 8 minutes. Turn ignition on. Using scan tool in SENSOR mode, monitor 1/1 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for at least 2 minutes. If voltage stays at.4-.6 volt, go to next step. If voltage does not stay at.4-.6 volt, go to step 7.
3. Disconnect 1/1 HO2S connector. See «1/1 OXYGEN SENSOR LOCATION»(ref-97638-S39564467952001051000000) table. Measure resistance between Dark Green/White and Brown/Violet wires at 1/1 HO2S connector (component side). If resistance is not 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T) with HO2S at 70°F (21°C), replace 1/1 HO2S. If resistance is 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T), 1/1 HO2S heater element is okay. Go to next step.
4. Disconnect Powertrain Control Module (PCM) connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/Violet wire between 1/1 HO2S harness connector and terminal No. 8 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Violet wire.
5. Ensure ignition is off. Reconnect PCM connectors. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Dark Green/White wire at 1/1 HO2S harness connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in 1/1 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay (Calif. emission vehicles with 5.2L and 5.9L light-duty) and 1/1 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0136 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0136 or displayed count is not "0", go to step 9.
2. Turn ignition off. Remove and inspect fuse "K" (15-amp) in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 Fuse "K" may also be referred to as O2 sensor fuse. If fuse is blown, go to next step. If fuse is okay, go to step 4.
3. Ensure fuse "K" is removed from PDC. Remove O2 HTR REAR relay from PDC. see scheme 3 Measure resistance between ground and terminals No. 30 and 86 at O2 HTR REAR socket in PDC. see scheme 3 If both resistance readings are 5 ohms or more, circuits are okay. Replace fuse. If any resistance reading is less than 5 ohms, repair short to ground in Dark Green/White wire. Replace fuse.
4. Remove O2 HTR REAR relay from PDC. see scheme 3 Measure resistance between terminals No. 85 and 86 at O2 HTR REAR relay (component side). If resistance is 100 ohms or less, go to next step. If resistance is more than 100 ohms, replay coil is defective. Replace O2 HTR REAR relay.
5. Measure resistance of Dark Green/White wire between terminal K2 (output side) at fuse holder for fuse "K" in PDC and terminals No. 30 and 86 at O2 HTR REAR socket in PDC. If both resistance readings are less than 5 ohms, go to next step. If any resistance reading is 5 ohms or more, repair open in appropriate Dark Green/White wire.
6. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Green/Pink wire between terminal No. 85 at O2 HTR REAR relay socket in PDC and terminal No. 9 at PCM C3 connector. see scheme 21and see scheme 3. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green/Pink wire.
7. Measure resistance between ground and terminal No. 85 (Dark Green/Pink wire) at O2 HTR REAR relay socket in PDC. see scheme 3 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green/Pink wire. See WIRING DIAGRAMS article.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0137 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0137 is not displayed or displayed count is not "0", go to step 8.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 1/2 HO2S voltage. If voltage is less than.16 volt, go to next step. If voltage is.16 volt or more, go to step 8.
3. Turn ignition off. Disconnect 1/2 HO2S connector. See «1/2 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S22662800722001051000000) table. Start engine and allow it to idle. Using scan tool, read 1/2 HO2S voltage. If voltage is.16 volt or less, go to next step. If voltage is more than.16 volt, replace 1/2 HO2S.
4. Turn ignition off. Ensure 1/2 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and oxygen sensor signal circuit at terminal No. 4 of 1/2 HO2S harness connector. See «1/2 HEATED OXYGEN SENSOR HARNESS CONNECTOR TERMINAL IDENTIFICATION»(ref-97638-S27491981562001052300000) table. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in oxygen sensor signal circuit between PCM and 1/2 HO2S. See WIRING DIAGRAMS article.
5. Measure resistance between terminals No. 3 and 4 at 1/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, oxygen sensor ground circuit is shorted to oxygen sensor signal circuit. Repair wiring as necessary.
6. Measure resistance between terminals No. 2 and 4 at 1/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, oxygen sensor signal circuit is shorted to oxygen sensor heater ground circuit. Repair wiring as necessary.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1/2 HEATED OXYGEN SENSOR LOCATION

1/2 HEATED OXYGEN SENSOR HARNESS CONNECTOR TERMINAL IDENTIFICATION

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0138 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0138 is not displayed or displayed count is not "0", go to step 9.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 1/2 HO2S voltage. If voltage is more than 1.2 volts, go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Turn ignition off. Disconnect 1/2 HO2S connector. See «1/2 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S22662800722001051000000) table. Start engine and allow it to idle. Using scan tool, read 1/2 HO2S voltage. If voltage is 1.2 volts or more, go to next step. If voltage is less than 1.2 volts, replace 1/2 HO2S.
4. Turn ignition off. Ensure 1/2 HO2S is still disconnected. Turn ignition on. Measure voltage between ground and oxygen sensor signal circuit at terminal No. 4 of 1/2 HO2S harness connector. See «1/2 HEATED OXYGEN SENSOR HARNESS CONNECTOR TERMINAL IDENTIFICATION»(ref-97638-S27491981562001052300000) table. If voltage is 1.2 volts or less, go to next step. If voltage is more than 1.2 volts, repair short to voltage in oxygen sensor signal circuit between PCM and 1/2 HO2S.
5. Turn ignition off. Measure resistance between terminals No. 1 and 4 at 1/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, power circuit to oxygen sensor heater is shorted to oxygen sensor signal circuit. Repair wiring as necessary. See WIRING DIAGRAMS article.
6. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 On 3.9L, 5.2L and 5.9L light-duty, measure resistance of Orange/Black wire between 1/2 HO2S harness connector and terminal No. 25 at PCM C1 harness connector. see scheme 21 On 8.0L Calif., measure resistance of Tan/White wire between 1/2 HO2S harness connector and terminal No. 29 at PCM C1 harness connector. see scheme 21 On all models, if resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange/Black wire or Tan/White wire.
7. Measure resistance of Black/Light Blue wire between 1/2 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0139 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0139 or displayed count is not "0", go to step 6.
2. Start engine and allow it to idle. Check exhaust system for leaks between engine and 1/2 HO2S. See «1/2 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S22662800722001051000000) table. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Ensure engine is still idling. On 3.9L, 5.2L and 5.9L light-duty, use a voltmeter and backprobe Orange/Black wire between 1/2 HO2S harness connector and terminal No. 25 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 On 8.0L Calif., use a voltmeter and backprobe Tan/White wire between 1/2 HO2S harness connector and terminal No. 29 at PCM C1 harness connector. On all models, if voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Orange/Black wire or Tan/White wire between 1/2 HO2S and PCM.
4. Using voltmeter, backprobe Black/Light Blue wire between 1/2 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Light Blue wire between 1/2 HO2S and PCM.
5. At this time, 1/2 HO2S is assumed to be defective. Replace 1/2 HO2S.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0141 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0141 or displayed count is not "0", go to step 3.
2. Turn ignition off. Allow HO2S to cool down for at least 8 minutes. Turn ignition on. Using scan tool in SENSOR mode, monitor 1/2 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 1/2 HO2S voltage for at least 2 minutes. If voltage stays at.4-.6 volt, go to next step. If voltage does not stay at.4-.6 volt, go to step 8.
3. Disconnect 1/2 HO2S connector. See «1/2 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S22662800722001051000000) table. Measure resistance between terminals No. 1 and 2 at 1/2 HO2S connector (component side). See «1/2 HEATED OXYGEN SENSOR HARNESS CONNECTOR TERMINAL IDENTIFICATION»(ref-97638-S27491981562001052300000) table. If resistance is not 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T) with HO2S at 70°F (21°C), replace 1/2 HO2S. If resistance is 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T), 1/2 HO2S heater element is okay. On Federal emission vehicles, go to next step. On Calif. emission vehicles, go to step 5.
4. Ensure ignition is off. Disconnect Powertrain Control Module (PCM) connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between 1/2 HO2S harness connector and terminal No. 16 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, reconnect PCM connectors and go to step 6. If resistance is 5 ohms or more, repair open in Brown/White wire.
5. Ensure ignition is off. Measure resistance between ground and Black/White wire at 1/2 HO2S harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/White wire.
6. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and terminal No. 1 at 1/2 HO2S harness connector. See «1/2 HEATED OXYGEN SENSOR HARNESS CONNECTOR TERMINAL IDENTIFICATION»(ref-97638-S27491981562001052300000) table. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in 1/2 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay (Calif. emission vehicles with 5.2L, 5.9L light-duty or 8.0L) and 1/2 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0143 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0143 is not displayed or displayed count is not "0", go to step 8.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 1/3 HO2S voltage. If voltage is less than.16 volt, go to next step. If voltage is.16 volt or more, go to step 8.
3. Turn ignition off. Disconnect 1/3 HO2S connector located on exhaust pipe, directly behind catalytic converters. Start engine and allow it to idle. Using scan tool, read 1/3 HO2S voltage. If voltage is.16 volt or less, go to next step. If voltage is more than.16 volt, replace 1/3 HO2S.
4. Turn ignition off. Ensure 1/3 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Orange/Black wire at 1/3 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Orange/Black wire between PCM and 1/3 HO2S. See WIRING DIAGRAMS article.
5. Measure resistance between Orange/Black and Black/Light Blue wires at 1/3 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange/Black and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. Measure resistance between Orange/Black and Black/White wires at 1/3 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange/Black and Black/White wires are shorted together. Repair wiring as necessary.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0144 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0144 is not displayed or displayed count is not "0", go to step 9.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 1/3 HO2S voltage. If voltage is more than 1.2 volts, go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Turn ignition off. Disconnect 1/3 HO2S connector located on exhaust pipe, directly behind catalytic converters. Start engine and allow it to idle. Using scan tool, read 1/3 HO2S voltage. If voltage is 1.2 volts or more, go to next step. If voltage is less than 1.2 volts, replace 1/3 HO2S.
4. Turn ignition off. Ensure 1/3 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Turn ignition on. Measure voltage between ground and Orange/Black wire at 1/3 HO2S harness connector. If voltage is 1.2 volts or less, go to next step. If voltage is more than 1.2 volts, repair short to voltage in Orange/Black wire between PCM and 1/3 HO2S.
5. Turn ignition off. Measure resistance between Orange/Black and Dark Green/Yellow wires at 1/3 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange/Black and Dark Green/Yellow wires are shorted together. Repair wiring as necessary. See WIRING DIAGRAMS article.
6. Measure resistance of Orange/Black wire between 1/3 HO2S harness connector and terminal No. 25 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange/Black wire.
7. Measure resistance of Black/Light Blue wire between 1/3 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0145 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0145 or displayed count is not "0", go to step 6.
2. Start engine and allow it to idle. Check exhaust system for leaks between engine and 1/3 HO2S. 1/3 HO2S connector is located on exhaust pipe, directly behind catalytic converters. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Ensure engine is still idling. Using a voltmeter, backprobe Orange/Black wire between 1/3 HO2S harness connector and terminal No. 25 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Orange/Black wire between 1/3 HO2S and PCM.
4. Using a voltmeter, backprobe Black/Light Blue wire between 1/3 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Light Blue wire between 1/3 HO2S and PCM.
5. At this time, 1/3 HO2S is assumed to be defective. Replace 1/3 HO2S.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0147 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0147 or displayed count is not "0", go to step 3.
2. Turn ignition off. Allow HO2S to cool down for at least 8 minutes. Turn ignition on. Using scan tool in SENSOR mode, monitor 1/3 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 1/3 HO2S voltage for at least 2 minutes. If voltage stays at.4-.6 volt, go to next step. If voltage does not stay at.4-.6 volt, go to step 7.
3. Disconnect 1/3 HO2S connector located on exhaust pipe, directly behind catalytic converters. Measure resistance between Dark Green/Yellow and Black/White wires at 1/3 HO2S connector (component side). If resistance is not 4-5 ohms with HO2S at 70°F (21°C), replace 1/3 HO2S. If resistance is 4-5 ohms, 1/3 HO2S heater element is okay. Go to next step.
4. Ensure ignition is off. Measure resistance between ground and Black/White wire at 1/3 HO2S harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/White wire.
5. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Dark Green/Yellow wire at 1/3 HO2S harness connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in 1/3 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay and 1/3 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0151 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0151 is not displayed or displayed count is not "0", go to step 8.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 2/1 HO2S voltage. If voltage is less than.16 volt, go to next step. If voltage is.16 volt or more, go to step 8.
3. Turn ignition off. Disconnect 2/1 HO2S connector. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S21679578362001051000000) table. Start engine and allow it to idle. Using scan tool, read 2/1 HO2S voltage. If voltage is.16 volt or less, go to next step. If voltage is more than.16 volt, replace 2/1 HO2S.
4. Turn ignition off. Ensure 2/1 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Light Green/Red wire at 2/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Light Green/Red wire between PCM and 2/1 HO2S. See WIRING DIAGRAMS article.
5. Measure resistance between Light Green/Red and Black/Light Blue wires at 2/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Light Green/Red and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. Measure resistance between Light Green/Red and Brown/White wires at 2/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Light Green/Red and Brown/White wires are shorted together. Repair wiring as necessary.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

2/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0152 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0152 is not displayed or displayed count is not "0", go to step 9.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 2/1 HO2S voltage. If voltage is more than 1.2 volts, go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Turn ignition off. Disconnect 2/1 HO2S connector. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S21679578362001051000000) table. Start engine and allow it to idle. Using scan tool, read 2/1 HO2S voltage. If voltage is 1.2 volts or more, go to next step. If voltage is less than 1.2 volts, replace 2/1 HO2S.
4. Turn ignition off. Ensure 2/1 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Turn ignition on. Measure voltage between ground and Light Green/Red wire at 2/1 HO2S harness connector. If voltage is 1.2 volts or less, go to next step. If voltage is more than 1.2 volts, repair short to voltage in Light Green/Red wire between PCM and 2/1 HO2S.
5. Turn ignition off. Measure resistance between Light Green/Red and Dark Green/White wires at 2/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Light Green/Red and Dark Green/White wires are shorted together. Repair wiring as necessary. See WIRING DIAGRAMS article.
6. Measure resistance of Light Green/Red wire between 2/1 HO2S harness connector and terminal No. 26 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Light Green/Red wire.
7. Measure resistance of Black/Light Blue wire between 2/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0153 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0153 or displayed count is not "0", go to step 6.
2. Start engine and allow it to idle. Check exhaust system for leaks between engine and 2/1 HO2S. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S21679578362001051000000) table. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Ensure engine is still idling. Using a voltmeter, backprobe Light Green/Red wire between 2/1 HO2S harness connector and terminal No. 26 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Light Green/Red wire between 2/1 HO2S and PCM.
4. Using a voltmeter, backprobe Black/Light Blue wire between 2/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Light Blue wire between 2/1 HO2S and PCM.
5. At this time, 2/1 HO2S is assumed to be defective. Replace 2/1 HO2S.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0155 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0155 or displayed count is not "0", go to step 3.
2. Turn ignition off. Allow HO2S to cool down for at least 8 minutes. Turn ignition on. Using scan tool in SENSOR mode, monitor 2/1 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for at least 2 minutes. If voltage stays at.4-.6 volt, go to next step. If voltage does not stay at.4-.6 volt, go to step 7.
3. Disconnect 2/1 HO2S connector. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S21679578362001051000000) table. Measure resistance between Dark Green/White and Brown/White wires at 2/1 HO2S connector (component side). If resistance is not 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T) with HO2S at 70°F (21°C), replace 2/1 HO2S. If resistance is 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T), 2/1 HO2S heater element is okay. Go to next step.
4. Ensure ignition is off. Disconnect Powertrain Control Module (PCM) connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between 2/1 HO2S harness connector and terminal No. 16 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, reconnect PCM connectors and go to next step. If resistance is 5 ohms or more, repair open in Brown/White wire.
5. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Dark Green/White wire at 2/1 HO2S harness connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in 2/1 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay (except 5.9L heavy-duty) and 2/1 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0157 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0157 is not displayed or displayed count is not "0", go to step 8.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 2/2 HO2S voltage. If voltage is less than.16 volt, go to next step. If voltage is.16 volt or more, go to step 8.
3. Turn ignition off. Disconnect 2/2 HO2S located on passenger's side exhaust pipe, just behind mini-catalytic converter. Start engine and allow it to idle. Using scan tool, read 2/2 HO2S voltage. If voltage is.16 volt or less, go to next step. If voltage is more than.16 volt, replace 2/2 HO2S.
4. Turn ignition off. Ensure 2/2 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Orange/Tan wire at 2/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Orange/Tan wire between PCM and 2/2 HO2S. See WIRING DIAGRAMS article.
5. Measure resistance between Orange/Tan and Black/Light Blue wires at 2/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange/Tan and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. Measure resistance between Orange/Tan and Black/White wires at 2/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange/Tan and Black/White wires are shorted together. Repair wiring as necessary.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter for DTC P0158 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0158 is not displayed or displayed count is not "0", go to step 9.
2. Start engine and allow it to idle for 4-5 minutes. Using scan tool, read 2/2 HO2S voltage. If voltage is more than 1.2 volts, go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Turn ignition off. Disconnect 2/2 HO2S located on passenger's side exhaust pipe, just behind mini-catalytic converter. Start engine and allow it to idle. Using scan tool, read 2/2 HO2S voltage. If voltage is 1.2 volts or more, go to next step. If voltage is less than 1.2 volts, replace 2/2 HO2S.
4. Turn ignition off. Ensure 2/2 HO2S is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Turn ignition on. Measure voltage between ground and Orange/Tan wire at 2/2 HO2S harness connector. If voltage is 1.2 volts or less, go to next step. If voltage is more than 1.2 volts, repair short to voltage in Orange/Tan wire between PCM and 2/2 HO2S.
5. Turn ignition off. Measure resistance between Orange/Tan and Dark Green/Yellow wires at 2/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange/Tan and Dark Green/Yellow wires are shorted together. Repair wiring as necessary. See WIRING DIAGRAMS article.
6. Measure resistance of Orange/Tan wire between 2/2 HO2S harness connector and terminal No. 29 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange/Tan wire.
7. Measure resistance of Black/Light Blue wire between 2/2 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0159 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0159 or displayed count is not "0", go to step 6.
2. Start engine and allow it to idle. Check exhaust system for leaks between engine and 2/2 HO2S. The 2/2 HO2S is located on passenger's side exhaust pipe, just behind mini-catalytic converter. Start engine and allow it to idle. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Ensure engine is still idling. Using a voltmeter, backprobe Orange/Tan wire between 2/2 HO2S harness connector and terminal No. 29 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Orange/Tan wire between 2/2 HO2S and PCM.
4. Using a voltmeter, backprobe Black/Light Blue wire between 2/2 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in Black/Light Blue wire between 2/2 HO2S and PCM.
5. At this time, 2/2 HO2S is assumed to be defective. Replace 2/2 HO2S.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0161 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0161 or displayed count is not "0", go to step 3.
2. Turn ignition off. Allow HO2S to cool down for at least 8 minutes. Turn ignition on. Using scan tool in SENSOR mode, monitor 2/2 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 2/2 HO2S voltage for at least 2 minutes. If voltage stays at.4-.6 volt, go to next step. If voltage does not stay at.4-.6 volt, go to step 7.
3. Disconnect 2/2 HO2S connector located on passenger's side exhaust pipe, just behind mini-catalytic converter. Measure resistance between Dark Green/Yellow and Black/White wires at 2/2 HO2S connector (component side). If resistance is not 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T) with HO2S at 70°F (21°C), replace 2/2 HO2S. If resistance is 4-5 ohms (except 5.9L Calif. with A/T) or 3.3-4.1 ohms (5.9L Calif. with A/T), 2/2 HO2S heater element is okay. Go to next step.
4. Measure resistance between ground and Black/White wire at 2/2 HO2S harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/White wire.
5. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Dark Green/Yellow wire at 2/2 HO2S harness connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in 2/2 HO2S heater voltage supply circuit between Auto Shutdown (ASD) relay, joint connector No. 2, fuse "K" (15-amp), oxygen sensor downstream relay and 2/2 oxygen sensor. Oxygen sensor downstream relay may also be referred to as O2 HTR REAR relay. Fuse "K" may also be referred to as O2 sensor fuse. ASD relay, oxygen sensor downstream relay, joint connector No. 2 and fuse "K" are located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 See WIRING DIAGRAMS.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0171 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0171 is not displayed or displayed count is not "0", go to step 16.
2. Turn ignition off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-97638-S14707392262001051000000). Remove test port cap from fuel rail. Install a 0-60 psi (0-4.2 kg/cm 2 ) fuel pressure gauge to test port on fuel rail. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST. Allow fuel pressure gauge to stabilize. Stop ASD fuel system activation. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is as specified, go to step 6. If fuel pressure is more than specified, replace pressure regulator. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article.
3. Turn ignition off. Release fuel pressure. Raise and support vehicle. Disconnect fuel pressure line from fuel pump module. Connect 5/16" Fuel Line Pressure Test Adapter Hose (6539 or 6631) between disconnected fuel line and fuel pump module. Connect fuel pressure gauge to fuel line adapter hose. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST and note fuel pressure. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is not within specification, stop ASD fuel system activation, and go to next step. If fuel pressure is within specification, stop ASD fuel system activation and release fuel pressure. Check for plugged or kinked fuel supply line between fuel rail and fuel pump module. Replace fuel supply line as necessary.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer is not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump.
6. Turn ignition off. Wait at least 10 minutes for HO2S to cool down. Turn ignition on. Using scan tool, read 1/1 HO2S voltage. If voltage is.4-.6 volt, go to next step. If voltage is not.4-.6 volt, go to step 13.
7. Turn ignition off. Wait at least 10 minutes to allow HO2S to cool. Turn ignition on. Using scan tool in SENSOR mode, monitor 1/1 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for 2 minutes. If voltage does not stay at.4-.6 volt, go to next step. If voltage stays at.4-.6 volt, replace 1/1 HO2S.
8. Ensure ignition is on. Ensure throttle plate is fully closed against stop. Using scan tool, read TP sensor voltage. If voltage is less than.92 volt, go to next step. If voltage is.92 volt or more, check throttle plate and linkage for binding. Repair throttle plate and linkage as necessary. If throttle plate and linkage are okay, replace TP sensor.
9. Ensure ignition is on. Using scan tool, read TP sensor voltage. Slowly open and close throttle plate while monitoring TP sensor voltage. If voltage change is smooth, go to next step. If voltage change is erratic, replace TP sensor.
10. Turn ignition off. Connect a vacuum gauge to manifold vacuum source. Start engine and allow it to idle. If engine will not idle, maintain a constant RPM. Using scan tool in SENSOR mode, monitor Manifold Absolute Pressure (MAP) vacuum value. Compare scan tool reading with vacuum gauge reading. If scan tool reading is within one in. Hg of vacuum gauge, turn ignition off and go to next step. If scan tool reading is not within one in. Hg of vacuum gauge reading, replace MAP sensor.
11. Turn ignition on. Using scan tool, read ECT sensor value. If engine coolant temperature is more than 180°F (82°C), allow engine coolant temperature to cool down to 150°F (66°C) before proceeding. If engine coolant temperature is 150°F (66°C) or less, start engine and monitor scan tool until engine coolant temperature reaches 180°F (82°C). If ECT sensor value increases smoothly and reaches at least 180°F (82°C), go to next step. If ECT sensor value increase is erratic or does not reach at least 180°F (82°C), check for cooling system problems. Repair cooling system as necessary. If cooling system is okay, replace ECT sensor.
12. Check the following additional items as possible mechanical problems: Engine vacuum must be at least 13 in. Hg with shift selector in Neutral. Engine valve timing must be within specification. Engine compression must be within specification. Engine exhaust system must be free of restrictions. Engine Positive Crankcase Ventilation (PCV) system (except 8.0L) or Closed Crankcase Ventilation (CCV) system (8.0L) must flow freely. Torque converter stall speed must be within specification. Power brake booster must have no internal leaks. Fuel must be free of contamination. Fuel injectors must be free of restrictions. Fuel injector control wires must be installed on correct injector. Repair any mechanical problems as necessary. If no mechanical problems exist, go to step 16.
13. Ensure ignition is on. Disconnect 1/1 HO2S connector. See «1/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S05464030182001052500000) table. Using scan tool, read 1/1 HO2S voltage. If voltage is not.4-.6 volt, go to next step. If voltage is.4-.6 volt, replace 1/1 HO2S.
14. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) at 1/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Black/Dark Green wire or Tan/White wire between PCM and 1/1 HO2S.
15. At this time, PCM is assumed to be defective. Replace PCM.
16. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0172 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0172 is not displayed or displayed count is not "0", go to step 18.
2. Turn ignition off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-97638-S14707392262001051000000). Remove test port cap from fuel rail. Install a 0-60 psi (0-4.2 kg/cm 2 ) fuel pressure gauge to test port on fuel rail. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST. Allow fuel pressure gauge to stabilize. Stop ASD fuel system activation. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is as specified, go to step 6. If fuel pressure is more than specified, replace pressure regulator. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article.
3. Turn ignition off. Release fuel pressure. Raise and support vehicle. Disconnect fuel pressure line from fuel pump module. Connect 5/16" Fuel Line Pressure Test Adapter Hose (6539 or 6631) between disconnected fuel line and fuel pump module. Connect fuel pressure gauge to fuel line adapter hose. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST and note fuel pressure. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is not within specification, stop ASD fuel system activation, and go to next step. If fuel pressure is within specification, stop ASD fuel system activation and release fuel pressure. Check for plugged or kinked fuel supply line between fuel rail and fuel pump module. Replace fuel supply line as necessary.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer is not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump.
6. Turn ignition off. Wait at least 10 minutes for HO2S to cool down. Turn ignition on. Using scan tool, read 1/1 HO2S voltage. If voltage is.4-.6 volt, go to next step. If voltage is not.4-.6 volt, go to step 14.
7. Turn ignition off. Wait at least 10 minutes to allow HO2S to cool. Turn ignition on. Using scan tool in SENSOR mode, monitor 1/1 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for 2 minutes. If voltage does not stay at.4-.6 volt, go to next step. If voltage stays at.4-.6 volt, replace 1/1 HO2S.
8. Start engine and warm to normal operating temperature. Ensure engine is operating in closed loop. Using scan tool, select SYSTEM TESTS, then perform PURGE VAPORS TEST. Observe SHORT TERM ADAPTIVE value on scan tool, then press "3 " to flow. If SHORT TERM ADAPTIVE value changes, turn ignition off and go to next step. If SHORT TERM ADAPTIVE value does not change, check evaporative emission system. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
9. Ensure ignition is on. Ensure throttle plate is fully closed against stop. Using scan tool, read TP sensor voltage. If voltage is less than.92 volt, go to next step. If voltage is.92 volt or more, check throttle plate and linkage for binding. Repair throttle plate and linkage as necessary. If throttle plate and linkage are okay, replace TP sensor.
10. Ensure ignition is on. Using scan tool, read TP sensor voltage. Slowly open and close throttle plate while monitoring TP sensor voltage. If voltage change is smooth, go to next step. If voltage change is erratic, replace TP sensor.
11. Turn ignition off. Connect a vacuum gauge to manifold vacuum source. Start engine and allow it to idle. If engine will not idle, maintain a constant RPM. Using scan tool in SENSOR mode, monitor Manifold Absolute Pressure (MAP) vacuum value. Compare scan tool reading with vacuum gauge reading. If scan tool reading is within one in. Hg of vacuum gauge, turn ignition off and go to next step. If scan tool reading is not within one in. Hg of vacuum gauge reading, replace MAP sensor.
12. Turn ignition on. Using scan tool, read ECT sensor value. If engine coolant temperature is more than 180°F (82°C), allow engine coolant temperature to cool down to 150°F (66°C) before proceeding. If engine coolant temperature is 150°F (66°C) or less, start engine and monitor scan tool until engine coolant temperature reaches 180°F (82°C). If ECT sensor value increases smoothly and reaches at least 180°F (82°C), go to next step. If ECT sensor value increase is erratic or does not reach at least 180°F (82°C), check for cooling system problems. Repair cooling system as necessary. If cooling system is okay, replace ECT sensor.
13. Check the following additional items as possible mechanical problems: Engine vacuum must be at least 13 in. Hg with shift selector in Neutral. Engine valve timing must be within specification. Engine compression must be within specification. Engine exhaust system must be free of restrictions. Engine Positive Crankcase Ventilation (PCV) system (except 8.0L) or Closed Crankcase Ventilation (CCV) system (8.0L) must flow freely. Torque converter stall speed must be within specification. Power brake booster must have no internal leaks. Fuel must be free of contamination. Fuel injectors must be free of restrictions. Fuel injector control wires must be installed on correct injector. Repair any mechanical problems as necessary. If no mechanical problems exist, go to step 18.
14. Ensure ignition is on. Disconnect 1/1 HO2S connector. See «1/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S05464030182001052500000) table. Using scan tool, read 1/1 HO2S voltage. If voltage is not.4-.6 volt, go to next step. If voltage is.4-.6 volt, replace 1/1 HO2S.
15. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) between 1/1 HO2S harness connector and terminal No. 24 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Dark Green wire or Tan/White wire between PCM and 1/1 HO2S.
16. Ensure ignition is off and 1/1 HO2S is disconnected. Reconnect PCM connectors. Start engine. Measure voltage between ground and Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) at 1/1 HO2S harness connector. If voltage is.6 volt or less, go to next step. If voltage is more than.6 volt, repair short to voltage in Black/Dark Green wire or Tan/White wire between PCM and 1/1 HO2S.
17. At this time, PCM is assumed to be defective. Replace PCM.
18. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0174 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0174 is not displayed or displayed count is not "0", go to step 16.
2. Turn ignition off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-97638-S14707392262001051000000). Remove test port cap from fuel rail. Install a 0-60 psi (0-4.2 kg/cm 2 ) fuel pressure gauge to test port on fuel rail. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST. Allow fuel pressure gauge to stabilize. Stop ASD fuel system activation. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is as specified, go to step 6. If fuel pressure is more than specified, replace pressure regulator. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article.
3. Turn ignition off. Release fuel pressure. Raise and support vehicle. Disconnect fuel pressure line from fuel pump module. Connect 5/16" Fuel Line Pressure Test Adapter Hose (6539 or 6631) between disconnected fuel line and fuel pump module. Connect fuel pressure gauge to fuel line adapter hose. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST and note fuel pressure. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is not within specification, stop ASD fuel system activation, and go to next step. If fuel pressure is within specification, stop ASD fuel system activation and release fuel pressure. Check for plugged or kinked fuel supply line between fuel rail and fuel pump module. Replace fuel supply line as necessary.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer is not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump.
6. Turn ignition off. Wait at least 10 minutes for HO2S to cool down. Turn ignition on. Using scan tool, read 2/1 HO2S voltage. If voltage is.4-.6 volt, go to next step. If voltage is not.4-.6 volt, go to step 13.
7. Turn ignition off. Wait at least 10 minutes to allow HO2S to cool. Turn ignition on. Using scan tool in SENSOR mode, monitor 2/1 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for 2 minutes. If voltage does not stay at.4-.6 volt, go to next step. If voltage stays at.4-.6 volt, replace 2/1 HO2S.
8. Ensure ignition is on. Ensure throttle plate is fully closed against stop. Using scan tool, read TP sensor voltage. If voltage is less than.92 volt, go to next step. If voltage is.92 volt or more, check throttle plate and linkage for binding. Repair throttle plate and linkage as necessary. If throttle plate and linkage are okay, replace TP sensor.
9. Ensure ignition is on. Using scan tool, read TP sensor voltage. Slowly open and close throttle plate while monitoring TP sensor voltage. If voltage change is smooth, go to next step. If voltage change is erratic, replace TP sensor.
10. Turn ignition off. Connect a vacuum gauge to manifold vacuum source. Start engine and allow it to idle. If engine will not idle, maintain a constant RPM. Using scan tool in SENSOR mode, monitor Manifold Absolute Pressure (MAP) vacuum value. Compare scan tool reading with vacuum gauge reading. If scan tool reading is within one in. Hg of vacuum gauge, turn ignition off and go to next step. If scan tool reading is not within one in. Hg of vacuum gauge reading, replace MAP sensor.
11. Turn ignition on. Using scan tool, read ECT sensor value. If engine coolant temperature is more than 180°F (82°C), allow engine coolant temperature to cool down to 150°F (66°C) before proceeding. If engine coolant temperature is 150°F (66°C) or less, start engine and monitor scan tool until engine coolant temperature reaches 180°F (82°C). If ECT sensor value increases smoothly and reaches at least 180°F (82°C), go to next step. If ECT sensor value increase is erratic or does not reach at least 180°F (82°C), check for cooling system problems. Repair cooling system as necessary. If cooling system is okay, replace ECT sensor.
12. Check the following additional items as possible mechanical problems: Engine vacuum must be at least 13 in. Hg with shift selector in Neutral. Engine valve timing must be within specification. Engine compression must be within specification. Engine exhaust system must be free of restrictions. Engine Positive Crankcase Ventilation (PCV) system (except 8.0L) or Closed Crankcase Ventilation (CCV) system (8.0L) must flow freely. Torque converter stall speed must be within specification. Power brake booster must have no internal leaks. Fuel must be free of contamination. Fuel injectors must be free of restrictions. Fuel injector control wires must be installed on correct injector. Repair any mechanical problems as necessary. If no mechanical problems exist, go to step 16.
13. Ensure ignition is on. Disconnect 2/1 HO2S connector. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S33630970522001052500000) table. Using scan tool, read 2/1 HO2S voltage. If voltage is not.4-.6 volt, go to next step. If voltage is.4-.6 volt, replace 2/1 HO2S.
14. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and Light Green/Red at 2/1 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Light Green/Red wire between PCM and 2/1 HO2S.
15. At this time, PCM is assumed to be defective. Replace PCM.
16. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

2/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0175 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0175 is not displayed or displayed count is not "0", go to step 18.
2. Turn ignition off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-97638-S14707392262001051000000). Remove test port cap from fuel rail. Install a 0-60 psi (0-4.2 kg/cm 2 ) fuel pressure gauge to test port on fuel rail. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST. Allow fuel pressure gauge to stabilize. Stop ASD fuel system activation. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is as specified, go to step 6. If fuel pressure is more than specified, replace pressure regulator. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article.
3. Turn ignition off. Release fuel pressure. Raise and support vehicle. Disconnect fuel pressure line from fuel pump module. Connect 5/16" Fuel Line Pressure Test Adapter Hose (6539 or 6631) between disconnected fuel line and fuel pump module. Connect fuel pressure gauge to fuel line adapter hose. Turn ignition on. Using scan tool, actuate ASD FUEL SYSTEM TEST and note fuel pressure. Fuel pressure should be 44.2-54.2 psi (3.10-3.81 kg/cm 2 ). If fuel pressure is not within specification, stop ASD fuel system activation, and go to next step. If fuel pressure is within specification, stop ASD fuel system activation and release fuel pressure. Check for plugged or kinked fuel supply line between fuel rail and fuel pump module. Replace fuel supply line as necessary.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. See FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer is not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump.
6. Turn ignition off. Wait at least 10 minutes for HO2S to cool down. Turn ignition on. Using scan tool, read 2/1 HO2S voltage. If voltage is.4-.6 volt, go to next step. If voltage is not.4-.6 volt, go to step 14.
7. Turn ignition off. Wait at least 10 minutes to allow HO2S to cool. Turn ignition on. Using scan tool in SENSOR mode, monitor 2/1 HO2S voltage until voltage stabilizes at.4-.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for 2 minutes. If voltage does not stay at.4-.6 volt, go to next step. If voltage stays at.4-.6 volt, replace 2/1 HO2S.
8. Start engine and warm to normal operating temperature. Ensure engine is operating in closed loop. Using scan tool, select SYSTEM TESTS, then perform PURGE VAPORS TEST. Observe SHORT TERM ADAPTIVE value on scan tool, then press "3 " to flow. If SHORT TERM ADAPTIVE value changes, turn ignition off and go to next step. If SHORT TERM ADAPTIVE value does not change, check evaporative emission system. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
9. Ensure ignition is on. Ensure throttle plate is fully closed against stop. Using scan tool, read TP sensor voltage. If voltage is less than.92 volt, go to next step. If voltage is.92 volt or more, check throttle plate and linkage for binding. Repair throttle plate and linkage as necessary. If throttle plate and linkage are okay, replace TP sensor.
10. Ensure ignition is on. Using scan tool, read TP sensor voltage. Slowly open and close throttle plate while monitoring TP sensor voltage. If voltage change is smooth, go to next step. If voltage change is erratic, replace TP sensor.
11. Turn ignition off. Connect a vacuum gauge to manifold vacuum source. Start engine and allow it to idle. If engine will not idle, maintain a constant RPM. Using scan tool in SENSOR mode, monitor Manifold Absolute Pressure (MAP) vacuum value. Compare scan tool reading with vacuum gauge reading. If scan tool reading is within one in. Hg of vacuum gauge, turn ignition off and go to next step. If scan tool reading is not within one in. Hg of vacuum gauge reading, replace MAP sensor.
12. Turn ignition on. Using scan tool, read ECT sensor value. If engine coolant temperature is more than 180°F (82°C), allow engine coolant temperature to cool down to 150°F (66°C) before proceeding. If engine coolant temperature is 150°F (66°C) or less, start engine and monitor scan tool until engine coolant temperature reaches 180°F (82°C). If ECT sensor value increases smoothly and reaches at least 180°F (82°C), go to next step. If ECT sensor value increase is erratic or does not reach at least 180°F (82°C), check for cooling system problems. Repair cooling system as necessary. If cooling system is okay, replace ECT sensor.
13. Check the following additional items as possible mechanical problems: Engine vacuum must be at least 13 in. Hg with shift selector in Neutral. Engine valve timing must be within specification. Engine compression must be within specification. Engine exhaust system must be free of restrictions. Engine Positive Crankcase Ventilation (PCV) system (except 8.0L) or Closed Crankcase Ventilation (CCV) system (8.0L) must flow freely. Torque converter stall speed must be within specification. Power brake booster must have no internal leaks. Fuel must be free of contamination. Fuel injectors must be free of restrictions. Fuel injector control wires must be installed on correct injector. Repair any mechanical problems as necessary. If no mechanical problems exist, go to step 18.
14. Ensure ignition is on. Disconnect 2/1 HO2S connector. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S33630970522001052500000) table. Using scan tool, read 2/1 HO2S voltage. If voltage is not.4-.6 volt, go to next step. If voltage is.4-.6 volt, replace 2/1 HO2S.
15. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Light Green/Red wire between 2/1 HO2S harness connector and terminal No. 26 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Light Green/Red wire between PCM and 2/1 HO2S.
16. Ensure ignition is off and 2/1 HO2S is disconnected. Reconnect PCM connectors. Start engine. Measure voltage between ground and Light Green/Red wire at 2/1 HO2S harness connector. If voltage is.6 volt or less, go to next step. If voltage is more than.6 volt, repair short to voltage in Light Green/Red wire between PCM and 2/1 HO2S.
17. At this time, PCM is assumed to be defective. Replace PCM.
18. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0201 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0201 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 1 connector. Fuel injector No. 1 is the first fuel injector back from front of driver's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 1. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 1 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 1. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 1. Using a test light connected to battery voltage, backprobe terminal No. 1 (White/Dark Blue wire) at fuel injector No. 1 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of White/Dark Blue wire between terminal No. 1 at fuel injector No. 1 harness connector and terminal No. 4 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in White/Dark Blue wire.
5. Measure resistance between ground and terminal No. 1 (White/Dark Blue wire) at fuel injector No. 1 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in White/Dark Blue wire between fuel injector No. 1 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0202 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0202 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 2 connector. Fuel injector No. 2 is the first fuel injector back from front of passenger's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 2. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 2 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 2. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 2. Using a test light connected to battery voltage, backprobe terminal No. 1 (Tan wire) at fuel injector No. 2 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Tan wire between terminal No. 1 at fuel injector No. 2 harness connector and terminal No. 15 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Tan wire.
5. Measure resistance between ground and terminal No. 1 (Tan wire) at fuel injector No. 2 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Tan wire between fuel injector No. 2 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0203 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0203 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 3 connector. Fuel injector No. 3 is the second fuel injector back from front of driver's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 3. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 3 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 3. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 3. Using a test light connected to battery voltage, backprobe terminal No. 1 (Yellow/White wire) at fuel injector No. 3 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Yellow/White wire between terminal No. 1 at fuel injector No. 3 harness connector and terminal No. 5 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Yellow/White wire.
5. Measure resistance between ground and terminal No. 1 (Yellow/White wire) at fuel injector No. 3 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Yellow/White wire between fuel injector No. 3 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0204 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0204 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 4 connector. Fuel injector No. 4 is the second fuel injector back from front of passenger's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 4. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 4 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 4. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 4. Using a test light connected to battery voltage, backprobe terminal No. 1 (Light Blue/Brown wire) at fuel injector No. 4 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Light Blue/Brown wire between terminal No. 1 at fuel injector No. 4 harness connector and terminal No. 16 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Light Blue/Brown wire.
5. Measure resistance between ground and terminal No. 1 (Light Blue/Brown wire) at fuel injector No. 4 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Light Blue/Brown wire between fuel injector No. 4 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0205 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0205 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 5 connector. Fuel injector No. 5 is the third fuel injector back from front of driver's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 5. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 5 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 5. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 5. Using a test light connected to battery voltage, backprobe terminal No. 1 (Gray wire) at fuel injector No. 5 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Gray wire between terminal No. 1 at fuel injector No. 5 harness connector and terminal No. 6 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Gray wire.
5. Measure resistance between ground and terminal No. 1 (Gray wire) at fuel injector No. 5 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Gray wire between fuel injector No. 5 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0206 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0206 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 6 connector. Fuel injector No. 6 is the third fuel injector back from front of passenger's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 6. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 6 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 6. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 6. Using a test light connected to battery voltage, backprobe terminal No. 1 (Brown/Dark Blue wire) at fuel injector No. 6 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Brown/Dark Blue wire between terminal No. 1 at fuel injector No. 6 harness connector and terminal No. 12 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Dark Blue wire.
5. Measure resistance between ground and terminal No. 1 (Brown/Dark Blue wire) at fuel injector No. 6 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Brown/Dark Blue wire between fuel injector No. 6 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0207 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0207 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 7 connector. Fuel injector No. 7 is the fourth fuel injector back from front of driver's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 7. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 7 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 7. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 7. Using a test light connected to battery voltage, backprobe terminal No. 1 (Violet/Tan wire) at fuel injector No. 7 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Violet/Tan wire between terminal No. 1 at fuel injector No. 7 harness connector and terminal No. 2 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/Tan wire.
5. Measure resistance between ground and terminal No. 1 (Violet/Tan wire) at fuel injector No. 7 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Violet/Tan wire between fuel injector No. 7 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0208 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0208 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 8 connector. Fuel injector No. 8 is the fourth fuel injector back from front of passenger's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 8. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 8 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 8. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 8. Using a test light connected to battery voltage, backprobe terminal No. 1 (Gray/Light Blue wire) at fuel injector No. 8 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Gray/Light Blue wire between terminal No. 1 at fuel injector No. 8 harness connector and terminal No. 13 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Gray/Light Blue wire.
5. Measure resistance between ground and terminal No. 1 (Gray/Light Blue wire) at fuel injector No. 8 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Gray/Light Blue wire between fuel injector No. 8 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0209 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0209 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 9 connector. Fuel injector No. 9 is the fifth fuel injector back from front of driver's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 9. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 9 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 9. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 9. Using a test light connected to battery voltage, backprobe terminal No. 1 (Tan/Black wire) at fuel injector No. 9 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Tan/Black wire between terminal No. 1 at fuel injector No. 9 harness connector and terminal No. 3 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Tan/Black wire.
5. Measure resistance between ground and terminal No. 1 (Tan/Black wire) at fuel injector No. 9 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Tan/Black wire between fuel injector No. 9 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0210 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0210 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect fuel injector No. 10 connector. Fuel injector No. 10 is the fifth fuel injector back from front of passenger's side of engine. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 10. Using a test light connected to ground, backprobe terminal No. 2 (Dark Green/Orange wire) at fuel injector No. 10 harness connector. see scheme 13 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to fuel injector No. 10. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 29
3. Reconnect fuel injector connector. Turn ignition on. Using scan tool, actuate FUEL INJECTOR NO. 10. Using a test light connected to battery voltage, backprobe terminal No. 1 (White wire) at fuel injector No. 10 harness connector. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of White wire between terminal No. 1 at fuel injector No. 10 harness connector and terminal No. 14 at PCM C2 harness connector. see scheme 13and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in White wire.
5. Measure resistance between ground and terminal No. 1 (White wire) at fuel injector No. 10 harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in White wire between fuel injector No. 10 and PCM.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If MISFIRE GOOD TRIP counter is displayed and displayed count is "0", go to next step. If MISFIRE GOOD TRIP counter is not displayed or displayed count is not "0", go to step 4 .
2. At this time, conditions required to set DTC are present. Using scan tool, read and record FREEZE FRAME and SIMILAR CONDITIONS data. Operate vehicle using data in SIMILAR CONDITIONS. While in SIMILAR CONDITIONS screen, go to WHICH CYLINDER IS MISFIRING monitor. If scan tool is counting misfires at this time, go to next step. If scan tool is not counting misfires at this time, go to step 4 .
3. Using scan tool, read and record FREEZE FRAME data. Using freeze frame data, attempt to determine cause of misfire. If adaptive fuel percentages are not more than plus or minus 15 percent, go to step 7 . If adaptive fuel percentages are more than plus or minus 15 percent, check fuel delivery. See FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
4. At this time, engine misfire does not exist or is an intermittent problem. Using scan tool, read and record FREEZE FRAME and SIMILAR CONDITIONS data. Road test vehicle under conditions in FREEZE FRAME and SIMILAR CONDITIONS data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If misfire or DTC returns, go to next step. If misfire or DTC does not return, no problem is indicated at this time. Test is complete.
5. Using scan tool, read and record FREEZE FRAME data. Using freeze frame data, attempt to determine cause of misfire. If adaptive fuel percentages are not more than plus or minus 15 percent, go to next step. If adaptive fuel percentages are more than plus or minus 15 percent, check fuel delivery. See FUEL SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article.
6. Using scan tool, read and record FREEZE FRAME and ENGINE RPM data. Using freeze frame data, attempt to determine cause of misfire. If engine speed is less than 3000 RPM and/or engine coolant temperature is not within normal range, go to next step. If engine speed is more than 3000 RPM and engine coolant temperature is within normal operating range, use lab scope to test CMP and CKP sensors, and check valve timing and engine vacuum.
7. Check the following additional items as possible mechanical problems: Engine vacuum must be at least 13 in. Hg with shift selector in Neutral. Engine valve timing must be within specification. Engine compression must be within specification. Engine exhaust system must be free of restrictions. Engine Positive Crankcase Ventilation (PCV) system must flow freely. Torque converter stall speed must be within specification. Power brake booster must have no internal leaks. Fuel must be free of contamination. Fuel injectors must be free of restrictions. Fuel injector control wires must be installed on correct injector. Repair mechanical problems as necessary. If no mechanical problems exist, go to next step.
8. Using scan tool, read and record FREEZE FRAME and LOAD VALUE data. Using freeze frame data, attempt to determine cause of misfire. If load value is 50 percent or less and/or engine coolant temperature is not within normal operating range, go to next step. If load value is more than 50 percent and engine coolant temperature is within normal operating range, check secondary ignition, compression and cylinder leakage.
9. Check following items for possible causes of cylinder misfire. Secondary Ignition Engine Mechanical Problem PCM Power Or Grounds Irregular CMP Sensor Signal Irregular CKP Sensor Signal Intake Restriction Damaged Trigger Wheel Accessory Drive Belt If any problems are found, repair as necessary. If no problems are found, test is complete. Check for any related technical service bulletins that may apply.

For diagnosis and repair procedure, see DTC P0300: MULTIPLE CYLINDER MISFIRE .

CYLINDER MISFIRE IDENTIFICATION

1. Turn ignition on. Using scan tool, read current CKP state while cranking engine. If scan tool displays current CKP state PRESENT, go to next step. If scan tool does not display current CKP state PRESENT, go to step 6. NOTE: The following step checks for any pulses generated on lab scope by the CKP sensor. With ignition on, no CKP sensor pulses should be generated.
2. Locate PCM in right rear corner of engine compartment. see scheme 2 Backprobe lab scope lead to terminal No. 8 (Gray/Black wire) at PCM C1 harness connector. see scheme 21 Observe lab scope screen and turn ignition on. If any pulses were generated when ignition was turned on, replace CKP sensor. If no pulses were generated, go to next step. NOTE: The following step checks for any pulses generated on lab scope by the CMP sensor. With ignition on, no CMP sensor pulses should be generated.
3. Turn ignition off. Disconnect lab scope. Backprobe lab scope lead to terminal No. 18 (Tan/Yellow wire) at PCM C1 harness connector. Observe lab scope screen and turn ignition on. If any pulses were generated when ignition was turned on, replace CMP sensor. If no pulses were generated, go to next step.
4. Turn ignition off. Backprobe lab scope lead to terminal No. 8 (Gray/Black wire) at PCM C1 harness connector. Observe lab scope screen and start engine. Wiggle wiring harness from CKP sensor to PCM while observing lab scope pattern. On 3.9L, 5.2L and 5.9L, CKP sensor is located on passenger's side of engine, just above the flywheel. (Scheme 108) On 8.0L, CKP sensor is located on passenger's side of cylinder block. (Scheme 109) On all models, if any irregularities in lab scope pattern occurs while wiggling wiring harness, check wiring harness where wiggling caused irregularity in lab scope pattern. Repair wiring as necessary. If wiring harness is okay, replace CKP sensor. If there are no irregularities in lab scope pattern while wiggling wiring harness, go to next step.
5. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
6. Turn ignition off. Disconnect CKP sensor. On 3.9L, 5.2L and 5.9L, CKP sensor is located on passenger's side of engine, just above the flywheel. (Scheme 108) On 8.0L, CKP sensor is located on passenger's side of cylinder block. (Scheme 109) On all models, turn ignition on. Measure voltage between ground and terminal No. 3 (Violet/White wire) at CKP sensor harness connector. see scheme 9 If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 15.
7. Measure voltage between ground and terminal No. 1 (Gray/Black wire) at CKP sensor harness connector. If voltage is 4.5-5.0 volts, go to next step. If voltage is not 4.5-5.0 volts, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Black/Light Blue wire between terminal No. 2 at CKP sensor harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
9. Turn ignition off. Remove CKP sensor. On 3.9L, inspect the 3 sets of double notches and 3 sets of single notches at outer edge of flexplate/flywheel for damage/debris. On 5.2L and 5.9L, inspect the 8 individual notches spaced every 45 degrees at outer edge of flexplate/flywheel for damage/debris. On 8.0L, inspect the 5 sets of double notches on the crankshaft counterweight for damage/debris. On all models, these notches cause a pulse to be generated when they pass under the CKP sensor. If notches are okay, replace CKP sensor. If notched areas are damaged or debris exists, repair or replace flexplate/flywheel (3.2L, 5.2L and 5.9L) or crankshaft (8.0L) as necessary.
10. Turn ignition off. Ensure CKP sensor is disconnected. Measure resistance between ground and terminal No. 1 (Gray/Black wire) at CKP sensor harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Gray/Black wire between PCM and CKP sensor.
11. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Gray/Black wire between terminal No. 1 at CKP sensor harness connector and terminal No. 8 at PCM C1 harness connector. see scheme 9and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Gray/Black wire.
12. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and terminal No. 1 (Gray/Black wire) at CKP sensor harness connector. If voltage is 5 volts or less, go to next step. If voltage is more than 5 volts, repair short to voltage in Gray/Black wire between CKP sensor and PCM.
13. Turn ignition off. Disconnect PCM connectors. Ensure CKP sensor is still disconnected. Measure resistance between terminals No. 1 (Gray/Black wire) and No. 3 (Violet/White wire) at CKP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Gray/Black and Violet/White wires are shorted together. Repair wiring as necessary.
14. At this time, PCM is assumed to be defective. Replace PCM.
15. Turn ignition off. Ensure CKP sensor is disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 3 (Violet/White wire) at CKP sensor harness connector. see scheme 9 If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Violet/White wire between PCM and CKP sensor.
16. Measure resistance of Violet/White wire between terminal No. 3 at CKP sensor harness connector and terminal No. 17 at PCM C1 harness connector. see scheme 9and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire.
17. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and terminal No. 3 (Violet/White wire) at CKP sensor harness connector. If voltage is 5.5 volts or less, go to next step. If voltage is more than 5.5 volts, repair short to voltage in Violet/White wire between CKP sensor and PCM.
18. At this time, PCM is assumed to be defective. Replace PCM.

Scheme 108

Scheme 109

1. Turn ignition on. Using scan tool, read current CMP state while cranking engine. If scan tool displays current CMP state PRESENT, go to next step. If scan tool does not display current CMP state PRESENT, go to step 6. NOTE: The following step checks for any pulses generated on lab scope by the CKP sensor. With ignition on, no CKP sensor pulses should be generated.
2. Turn ignition off. Backprobe lab scope lead to terminal No. 8 (Gray/Black wire) at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 Observe lab scope screen and turn ignition on. If any pulses were generated when ignition was turned on, replace CKP sensor. If no pulses were generated, go to next step. NOTE: The following step checks for any pulses generated on lab scope by the CMP sensor. With ignition on, no CMP sensor pulses should be generated.
3. Turn ignition off. Disconnect lab scope. Backprobe lab scope lead to terminal No. 18 (Tan/Yellow wire) at PCM C1 harness connector. Observe lab scope screen and turn ignition on. If any pulses were generated when ignition was turned on, replace CMP sensor. If no pulses were generated, go to next step.
4. Turn ignition off. Ensure lab scope lead is still connected to terminal No. 18 (Tan/Yellow wire) at PCM C1 harness connector. Observe lab scope screen and start engine. Wiggle wiring harness from CMP sensor to PCM while observing lab scope pattern. If any irregularities in lab scope pattern occurs while wiggling wiring harness, check wiring harness where wiggling caused irregularity in lab scope pattern. Repair wiring as necessary. If wiring harness is okay, replace CMP sensor. If there are no irregularities in lab scope pattern while wiggling wiring harness, go to next step.
5. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
6. Turn ignition off. Disconnect CMP sensor connector. On 3.2L, 5.2L and 5.9L, CMP is located inside distributor. (Scheme 110) On 8.0L, CMP sensor is located on timing chain cover at driver's side of engine. (Scheme 111) On all models, turn ignition on. Measure voltage between ground and terminal No. 3 (Violet/White wire) at CMP sensor harness connector. see scheme 5 If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 15.
7. Measure voltage between ground and terminal No. 1 (Violet/White wire) at CMP sensor harness connector. If voltage is 4.5-5.0 volts, go to next step. If voltage is not 4.5-5.0 volts, go to step 10.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Black/Light Blue wire between terminal No. 2 at CMP sensor harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 5and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire.
9. On 3.2L, 5.2L and 5.9L, remove CMP sensor from distributor. Inspect pulse ring for damage and ensure pulse ring rotates while cranking engine. Pulse ring is located in the distributor below CMP sensor. (Scheme 110) If pulse ring is okay and rotates while cranking engine, replace CMP sensor. If pulse ring is damaged or fails to rotate while cranking engine, repair or replace pulse ring as necessary. On 8.0L, remove CMP sensor. Inspect camshaft sprocket for damage. If camshaft sprocket is okay, replace CMP sensor. If camshaft sprocket is damaged. Repair or replace camshaft sprocket as necessary.
10. Turn ignition off. Ensure CMP sensor connector is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and terminal No. 1 (Tan/Yellow wire) at CMP harness connector. If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Tan/Yellow wire between CMP sensor and PCM.
11. Measure resistance of Tan/Yellow wire between terminal No. 1 at CMP sensor harness connector and terminal No. 18 at PCM C1 harness connector. see scheme 5and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Tan/Yellow wire.
12. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and terminal No. 1 (Tan/Yellow wire) at CMP sensor harness connector. If voltage is 5 volts or less, go to next step. If voltage is more than 5 volts, repair short to voltage in Tan/Yellow wire between CMP sensor and PCM.
13. Turn ignition off. Disconnect PCM connectors. Ensure CMP sensor is still disconnected. Measure resistance between terminals No. 1 (Tan/Yellow wire) and No. 3 (Violet/White wire) at CMP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Tan/Yellow and Violet/White wires are shorted together. Repair wiring as necessary.
14. At this time, PCM is assumed to be defective. Replace PCM.
15. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 3 (Violet/White wire) at CMP harness connector. see scheme 5 If resistance is 100 ohms or more, go to next step. If resistance is less than 100 ohms, repair short to ground in Violet/White wire between PCM and CMP sensor.
16. Measure resistance of Violet/White wire between terminal No. 3 at CMP sensor harness connector and terminal No. 17 at PCM C1 harness connector. see scheme 5and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire.
17. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and terminal No. 3 (Violet/White wire) at CMP sensor harness connector. If voltage is 5.5 volts or less, go to next step. If voltage is more than 5.5 volts, repair short to voltage in Violet/White wire between CMP sensor and PCM.
18. At this time, PCM is assumed to be defective. Replace PCM.

Scheme 110

Scheme 111

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0351 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0351 or displayed count is not "0", go to step 8.
2. Turn ignition off. Disconnect ignition coil connector. Ignition coil is mounted on front of right cylinder head. Measure resistance between ignition coil terminals. This will check ignition coil primary resistance. Resistance should be.6-.9 ohm at 70-80°F (21-27°C). If resistance is as specified, go to next step. If resistance is not as specified, replace ignition coil.
3. Turn ignition on. Using scan tool, actuate Auto Shutdown (ASD) relay. Using a test light connected to ground, probe terminal No. 1 (Dark Green/Orange wire) at ignition coil harness connector. see scheme 16 If test light illuminates brightly, stop relay activation and go to next step. If test light does not illuminate brightly, repair open or high resistance in Dark Green/Orange wire between ASD relay and ignition coil. ASD relay is located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2
4. Using a test light connected to positive battery voltage, probe terminal No. 2 (Black/Gray wire) at ignition coil harness connector while cranking engine for 5 seconds. If test light does not blink/flicker, go to next step. If test light blinks/flickers, go to step 8.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Black/Gray wire between ignition coil harness connector and terminal No. 7 at PCM C1 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open Black/Gray wire.
6. Measure resistance between ground and terminal No. 2 (Black/Gray wire) at ignition coil harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Black/Gray wire between ignition coil and PCM.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. Also listen for engine to miss/stall. If value changes or engine misses/stalls while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change or engine to miss/stall. If value does not change and engine does not miss/stall, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Pay particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Disconnect spark plug wire at cylinder No. 6. Cylinder No. 6 is third cylinder back from front of engine on passenger's side of engine. Connect spark plug wire to spark tester. Connect spark tester to good ground. Turn ignition on. Using scan tool, actuate ignition coil No. 1 and check for spark. If good spark exists, go to next step. If good spark does not exist, go to step 5.
2. Ensure ignition coil No. 1 is still actuated and spark tester is connected to ground. Monitor spark while wiggling wiring harness and connectors between PCM and front ignition coil pack. PCM is located in right rear corner of engine compartment. see scheme 2 Front ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to timing chain end of engine. This is the largest ignition coil pack which may also be referred to as ignition coil 6-pack, as it provides spark to 6 cylinders. If spark does not stop or become erratic while wiggling wiring harness and connectors, go to next step. If spark stops or becomes erratic while wiggling wiring harness, repair wiring or connectors as necessary.
3. Stop actuation of ignition coil No. 1. Turn ignition off. Inspect wiring harness and connectors between PCM and front ignition coil pack. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary.
4. At this time, conditions for ignition coil No. 1 primary circuit malfunction do not exist or an intermittent problem with connectors or wiring harness exists. Using scan tool, read FREEZE FRAME data and attempt to duplicate conditions when DTC was set. Inspect PCM connectors and front ignition coil pack connector for corroded, pushed out or damaged terminals. Inspect wiring harness between PCM and front ignition coil pack for any possible intermittent problems. Also check for any related technical service bulletins. Repair connectors and wiring harness as necessary. If no problems are indicated, test is complete.
5. Turn ignition off. Disconnect front ignition coil pack connector. Front ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to timing chain end of engine. This is the largest ignition coil pack which may also be referred to as ignition coil 6-pack, as it provides spark to 6 cylinders. Turn ignition on. Using scan tool, actuate ignition coil No. 1. Measure voltage between ground and terminal No. 2 (Dark Green/Orange wire) at front ignition coil pack harness connector. see scheme 17 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to front ignition coil pack. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 2
6. Stop actuation of ignition coil No. 1. Turn ignition off. Inspect front ignition coil pack connector for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair as necessary.
7. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Black/Gray wire between terminals No. 1 at front ignition coil pack harness connector and No. 7 at PCM C1 harness connector. see scheme 17and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Gray wire.
8. Ensure front ignition coil pack connector and PCM connectors are still disconnected. Measure resistance between ground and terminal No. 1 (Black/Gray wire) at front ignition coil pack harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Black/Gray wire between front ignition coil pack and PCM.
9. Measure ignition coil primary resistance between terminals on front ignition coil pack that corresponds with Black/Gray and Dark Green/Orange wires at front ignition coil pack harness connector. If ignition coil primary resistance is less than 2 ohms, replace PCM. If ignition coil primary resistance is 2 ohms or more, replace front ignition coil pack.

1. Disconnect spark plug wire at cylinder No. 5. Cylinder No. 5 is third cylinder back from front of engine on driver's side of engine. Connect spark plug wire to spark tester. Connect spark tester to good ground. Turn ignition on with engine off. Using scan tool, actuate ignition coil No. 2 and check for spark. If good spark exists, go to next step. If good spark does not exist, go to step 5.
2. Ensure ignition coil No. 2 is still actuated and spark tester is connected to ground. Monitor spark while wiggling wiring harness and connectors between PCM and rear ignition coil pack. PCM is located in right rear corner of engine compartment. see scheme 2 Rear ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to the firewall. This is the smallest ignition coil pack which may also be referred to as ignition coil 4-pack, as it provides spark to 4 cylinders. If spark does not stop or become erratic while wiggling wiring harness and connectors, go to next step. If spark stops or becomes erratic while wiggling wiring harness, repair wiring or connectors as necessary.
3. Stop actuation of ignition coil No. 2. Turn ignition off. Inspect wiring harness and connectors between PCM and rear ignition coil pack. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary.
4. At this time, conditions for ignition coil No. 2 primary circuit malfunction does not exist or is an intermittent problem with connectors or wiring harness. Using scan tool, read FREEZE FRAME data and attempt to duplicate the conditions when DTC was set. Inspect PCM connectors and rear ignition coil pack connector for corroded, pushed out or damaged terminals. Inspect wiring harness between PCM and rear ignition coil pack for any possible intermittent problems. Also check for any related technical service bulletins. Repair connectors and wiring harness as necessary. If no problems are indicated, test is complete.
5. Turn ignition off. Disconnect rear ignition coil pack connector. Rear ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to the firewall. This is the smallest ignition coil pack which may also be referred to as ignition coil 4-pack, as it provides spark to 4 cylinders. Turn ignition on. Using scan tool, actuate ignition coil No. 2. Measure voltage between ground and terminal No. 2 (Dark Green/Orange wire) at rear ignition coil pack harness connector. see scheme 18 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to rear ignition coil pack. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 2
6. Stop actuation of ignition coil No. 2. Turn ignition off. Inspect rear ignition coil pack connector for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair as necessary.
7. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Blue/White wire between terminals No. 1 at rear ignition coil pack harness connector and No. 9 at PCM C1 harness connector. see scheme 18and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Blue/White wire.
8. Ensure rear ignition coil pack connector and PCM connectors are still disconnected. Measure resistance between ground and terminal No. 1 (Dark Blue/White wire) at rear ignition coil pack harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue/White wire between rear ignition coil pack and PCM.
9. Measure ignition coil primary resistance between terminals on rear ignition coil pack that corresponds with Dark Blue/White and Dark Green/Orange wires in rear ignition coil pack harness connector. If ignition coil primary resistance is less than 2 ohms, replace PCM. If ignition coil primary resistance is 2 ohms or more, replace rear ignition coil pack.

1. Disconnect spark plug wire at cylinder No. 8. Cylinder No. 8 is fourth cylinder back from front of engine on passenger's side of engine. Connect spark plug wire to spark tester. Connect spark tester to good ground. Turn ignition on. Using scan tool, actuate ignition coil No. 3 and check for spark. If good spark exists, go to next step. If good spark does not exist, go to step 5.
2. Ensure ignition coil No. 3 is still actuated and spark tester is connected to ground. Monitor spark while wiggling wiring harness and connectors between PCM and rear ignition coil pack. PCM is located in right rear corner of engine compartment. see scheme 2 Rear ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to the firewall. This is the smallest ignition coil pack which may also be referred to as ignition coil 4-pack, as it provides spark to 4 cylinders. If spark does not stop or become erratic while wiggling wiring harness and connectors, go to next step. If spark stops or becomes erratic while wiggling wiring harness, repair wiring or connectors as necessary.
3. Stop actuation of ignition coil No. 3. Turn ignition off. Inspect wiring harness and connectors between PCM and rear ignition coil pack. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary.
4. At this time, conditions for ignition coil No. 3 primary circuit malfunction does not exist or is an intermittent problem with connectors or wiring harness. Using scan tool, read FREEZE FRAME data and attempt to duplicate the conditions when DTC was set. Inspect PCM connectors and rear ignition coil pack connector for corroded, pushed out or damaged terminals. Inspect wiring harness between PCM and rear ignition coil pack for any possible intermittent problems. Also check for any related technical service bulletins. Repair connectors and wiring harness as necessary. If no problems are indicated, test is complete.
5. Turn ignition off. Disconnect rear ignition coil pack connector. Rear ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to the firewall. This is the smallest ignition coil pack which may also be referred to as ignition coil 4-pack, as it provides spark to 4 cylinders. Turn ignition on. Using scan tool, actuate ignition coil No. 3. Measure voltage between ground and terminal No. 2 (Dark Green/Orange wire) at rear ignition coil pack harness connector. see scheme 18 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to rear ignition coil pack. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 2
6. Stop actuation of ignition coil No. 3. Turn ignition off. Inspect rear ignition coil pack connector for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair as necessary.
7. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Red/Black wire between terminals No. 3 at rear ignition coil pack harness connector and No. 3 at PCM C1 harness connector. see scheme 18and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Red/Black wire.
8. Ensure rear ignition coil pack connector and PCM connectors are still disconnected. Measure resistance between ground and terminal No. 3 (Red/Black wire) at rear ignition coil pack harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Red/Black wire between rear ignition coil pack and PCM.
9. Measure ignition coil primary resistance between terminals at rear ignition coil pack that corresponds with Red/Black and Dark Green/Orange wires at rear ignition coil pack harness connector. If ignition coil primary resistance is less than 2 ohms, replace PCM. If ignition coil primary resistance is 2 ohms or more, replace rear ignition coil pack.

1. Disconnect spark plug wire at cylinder No. 4. Cylinder No. 4 is second cylinder back from front of engine on passenger's side of engine. Connect spark plug wire to spark tester. Connect spark tester to good ground. Turn ignition on. Using scan tool, actuate ignition coil No. 4 and check for spark. If good spark exists, go to next step. If good spark does not exist, go to step 5.
2. Ensure ignition coil No. 4 is still actuated and spark tester is connected to ground. Monitor spark while wiggling wiring harness and connectors between PCM and front ignition coil pack. PCM is located in right rear corner of engine compartment. see scheme 2 Front ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to timing chain end of engine. This is the largest ignition coil pack which may also be referred to as ignition coil 6-pack, as it provides spark to 6 cylinders. If spark does not stop or become erratic while wiggling wiring harness and connectors, go to next step. If spark stops or becomes erratic while wiggling wiring harness, repair wiring or connectors as necessary.
3. Stop actuation of ignition coil No. 4. Turn ignition off. Inspect wiring harness and connectors between PCM and front ignition coil pack. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary.
4. At this time, conditions for ignition coil No. 4 primary circuit malfunction does not exist or is an intermittent problem with connectors or wiring harness. Using scan tool, read FREEZE FRAME data and attempt to duplicate the conditions when DTC was set. Inspect PCM connectors and front ignition coil pack connector for corroded, pushed out or damaged terminals. Inspect wiring harness between PCM and front ignition coil pack for any possible intermittent problems. Also check for any related technical service bulletins. Repair connectors and wiring harness as necessary. If no problems are indicated, test is complete.
5. Turn ignition off. Disconnect front ignition coil pack connector. Front ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to timing chain end of engine. This is the largest ignition coil pack which may also be referred to as ignition coil 6-pack, as it provides spark to 6 cylinders. Turn ignition on. Using scan tool, actuate ignition coil No. 4. Measure voltage between ground and terminal No. 2 (Dark Green/Orange wire) at front ignition coil pack harness connector. see scheme 17 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open on Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to front ignition coil pack. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 2
6. Stop actuation of ignition coil No. 4. Turn ignition off. Inspect front ignition coil pack connector for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair as necessary.
7. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Yellow/Gray wire between terminals No. 3 at front ignition coil pack harness connector and No. 1 at PCM C1 harness connector. see scheme 17and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Yellow/Gray wire.
8. Ensure front ignition coil pack connector and PCM connectors are still disconnected. Measure resistance between ground and terminal No. 3 (Yellow/Gray wire) at front ignition coil pack harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Yellow/Gray wire between front ignition coil pack and PCM.
9. Measure ignition coil primary resistance between terminals on front ignition coil pack that corresponds with Yellow/Gray and Dark Green/Orange wires in front ignition coil pack harness connector. If ignition coil primary resistance is less than 2 ohms, replace PCM. If ignition coil primary resistance is 2 ohms or more, replace front ignition coil pack.

1. Disconnect spark plug wire at cylinder No. 2. Cylinder No. 2 is first cylinder back from front of engine on passenger's side of engine. Connect spark plug wire to spark tester. Connect spark tester to good ground. Turn ignition on. Using scan tool, actuate ignition coil No. 5 and check for spark. If good spark exists, go to next step. If good spark does not exist, go to step 5.
2. Ensure ignition coil No. 5 is still actuated and spark tester is connected to ground. Monitor spark while wiggling wiring harness and connectors between PCM and front ignition coil pack. PCM is located in right rear corner of engine compartment. see scheme 2 Front ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to timing chain end of engine. This is the largest ignition coil pack which may also be referred to as ignition coil 6-pack, as it provides spark to 6 cylinders. If spark does not stop or become erratic while wiggling wiring harness and connectors, go to next step. If spark stops or becomes erratic while wiggling wiring harness, repair wiring or connectors as necessary.
3. Stop actuation of ignition coil No. 5. Turn ignition off. Inspect wiring harness and connectors between PCM and front ignition coil pack. If no problems exist, go to next step. If any problems exist, repair wiring or connectors as necessary.
4. At this time, conditions for ignition coil No. 5 primary circuit malfunction does not exist or is an intermittent problem with connectors or wiring harness. Using scan tool, read FREEZE FRAME data and attempt to duplicate the conditions when DTC was set. Inspect PCM connectors and front ignition coil pack connector for corroded, pushed out or damaged terminals. Inspect wiring harness between PCM and front ignition coil pack for any possible intermittent problems. Also check for any related technical service bulletins. Repair connectors and wiring harness as necessary. If no problems are indicated, test is complete.
5. Turn ignition off. Disconnect front ignition coil pack connector. Front ignition coil pack is mounted on passenger's side of engine, just above valve cover and is the ignition coil pack closest to timing chain end of engine. This is the largest ignition coil pack which may also be referred to as ignition coil 6-pack, as it provides spark to 6 cylinders. Turn ignition on. Using scan tool, actuate ignition coil No. 5. Measure voltage between ground and at terminal No. 2 (Dark Green/Orange wire) at front ignition coil pack harness connector. see scheme 17 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open on Dark Green/Orange wire from ASD relay, through joint connector No. 2 and to front ignition coil pack. ASD relay and joint connector No. 2 are located in power distribution center on left side of engine compartment. see scheme 2
6. Stop actuation of ignition coil No. 5. Turn ignition off. Inspect front ignition coil pack connector for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair as necessary.
7. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Green/Gray wire between terminals No. 4 at front ignition coil pack harness connector and No. 5 at PCM C1 harness connector. see scheme 17and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green/Gray wire.
8. Ensure front ignition coil pack connector and PCM connectors are still disconnected. Measure resistance between ground and terminal No. 4 (Dark Green/Gray wire) at front ignition coil pack harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green/Gray wire between front ignition coil pack and PCM.
9. Measure ignition coil primary resistance between terminals on front ignition coil pack that corresponds with Dark Green/Gray and Dark Green/Orange wires in front ignition coil pack harness connector. If ignition coil primary resistance is less than 2 ohms, replace PCM. If ignition coil primary resistance is 2 ohms or more, replace front ignition coil pack.

1. Turn ignition on. Using scan tool, read DTCs. If any HO2S DTCs are present with P0420, repair those DTCs before continuing with this test. If GOOD TRIP counter is not displayed for DTC P0420 or displayed count is not "0", go to next step. If GOOD TRIP counter is displayed for DTC P0420 and displayed count is "0", go to step 3 .
2. Conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
3. Start engine and allow engine to idle. Check for exhaust leaks between engine and downstream HO2S. Downstream HO2S is located on exhaust pipe behind 1/1 catalytic converter. If no exhaust leaks exist, go to next step. If exhaust leaks exist, repair exhaust system as necessary.
4. Check exhaust for excessive smoke caused by coolant entering combustion chambers or high oil consumption. If excessive smoke caused by coolant entering combustion chambers or high oil consumption does not exist, go to next step. If excessive smoke caused by coolant entering combustion chambers or high oil consumption exists, repair engine as necessary and replace 1/1 catalytic converter.
5. Determine if downstream HO2S has been replaced without replacing upstream 1/1 HO2S, as a newly installed downstream HO2S used with an existing aging upstream 1/1 HO2S may cause DTC to set. If downstream HO2S has been replaced without replacing upstream 1/1 HO2S, replace upstream 1/1 HO2S. See «1/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S12362493272001053000000) table. If downstream HO2S has not been replaced without replacing upstream 1/1 HO2S, replace 1/1 catalytic converter.

1/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, read DTCs. If any HO2S DTCs are present with P0420, repair those DTCs before continuing with this test. If GOOD TRIP counter is not displayed for DTC P0420 or displayed count is not "0", go to next step. If GOOD TRIP counter is displayed for DTC P0420 and displayed count is "0", go to step 3 .
2. Conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
3. Start engine and allow engine to idle. Check exhaust for excessive smoke caused by coolant entering combustion chambers or high oil consumption. If excessive smoke caused by coolant entering combustion chambers or high oil consumption does not exist, go to next step. If excessive smoke caused by coolant entering combustion chambers or high oil consumption exists, repair engine as necessary and replace 2/1 catalytic converter.
4. Check for exhaust leaks between engine and downstream HO2S. Downstream HO2S is located on exhaust pipe behind catalytic converter. If no exhaust leaks exist, go to next step. If exhaust leaks exist, repair exhaust system as necessary.
5. Determine if downstream HO2S sensor has been replaced without replacing upstream 2/1 HO2S, as a newly installed downstream HO2S with an existing aging upstream HO2S may cause DTC to be set. If downstream HO2S has been replaced without replacing upstream 2/1 HO2S, replace upstream 2/1 HO2S. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S35643479002001053000000) table. If downstream HO2S has not been replaced without replacing upstream 2/1 HO2S, replace 2/1 catalytic converter.

2/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0441 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0441 or displayed count is not "0", go to step 8.
2. Inspect EVAP canisters for damage or signs of fuel entering EVAP canisters which may indicate a defective rollover valve on top of fuel tank. Two EVAP canisters are located on outside of passenger's frame rail, directly below rear of the cab. Depending on fuel tank size, vehicle may be equipped with one or 2 rollover valves. Rollover valve(s) is located on top of fuel tank. Rollover valve located on top of fuel pump module may be serviced separately. If top/rear rollover valve is defective, fuel tank must be replaced. If EVAP canisters are not damaged and no signs of fuel entering EVAP canisters exist, go to next step. If EVAP canisters are damaged or signs of fuel entering EVAP canisters exist, repair or replace EVAP canisters and rollover valves as necessary.
3. Visually inspect EVAP purge hose between EVAP canister and fuel tank. Check for plugged, pinched, ripped or dry-rotted hose. Replace EVAP purge hose as necessary. If EVAP purge hose is okay, go to next step.
4. Visually inspect EVAP purge hose between EVAP canister and EVAP purge solenoid. EVAP purge solenoid may be located on firewall, near brake booster or near passenger's side front corner of engine compartment. (Scheme 112) Check for plugged, pinched, ripped or dry-rotted hose. Replace EVAP purge hose as necessary. If EVAP purge hose is okay, go to next step.
5. Visually inspect vacuum hose between EVAP purge solenoid and throttle body. Check for plugged, pinched, ripped or dry-rotted hose. Replace vacuum hose as necessary. If vacuum hose is okay, check for plugged throttle body vacuum nipple. Repair vacuum nipple as necessary. If vacuum nipple is okay, go to next step.
6. Disconnect EVAP purge solenoid vacuum hoses. Using a vacuum pump, apply 10 in. Hg to EVAP purge solenoid vacuum source port. If vacuum holds, go to next step. If vacuum does not hold, replace EVAP canister purge valve.
7. Using a vacuum pump, apply 10 in. Hg to EVAP purge solenoid vacuum source port. Turn ignition on. Using scan tool, actuate EVAP PURGE SOLENOID and observe vacuum gauge. If vacuum holds, replace EVAP purge solenoid. If vacuum releases, no problem is indicated at this time. Test is complete.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Using scan tool, review FREEZE FRAME data. Attempt to duplicate condition that caused DTC to set. Visually inspect related connectors and wiring harness for damage. Check for any related technical service bulletins that may apply. Turn ignition on. Using scan tool, actuate EVAP PURGE SOLENOID. Wiggle EVAP purge solenoid wiring harness and listen for EVAP purge solenoid to quit actuating. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and displayed count changes to "0", or EVAP purge solenoid quits actuating, repair wiring where wiggling caused EVAP purge solenoid to quit actuating. If EVAP purge solenoid does not stop actuating and GOOD TRIP counter is not displayed or displayed count does not change to "0", no problem is indicated at this time. Test is complete.

Scheme 112

Note. A loose fuel tank cap could cause this trouble code to set. Ensure fuel tank cap is tight and in good condition.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is not displayed for DTC or displayed count is not "0", go to step 4. If GOOD TRIP counter is displayed for DTC and displayed count is "0", go to next step.
2. To test EVAP system properly, fuel tank should have 20-80 percent of fuel capacity. Miller Evaporative System Testing Kit (6872A) and Gas Cap Adapter (8382) are used to perform evaporative system pressure test. Connect scan tool to Data Link Connector (DLC). Connect EVAP system testing kit positive lead to positive battery terminal and negative lead to negative battery terminal. Using EVAP system testing kit, and instructions printed on EVAP system testing kit cover, perform EVAP system pressure pump self-test. Remove gas cap and install gas cap adapter to fuel tank. Install gas cap to gas cap adapter. Connect pressure supply hose from evaporative system testing kit to fitting on gas cap adapter. Disconnect vacuum supply hose at Leak Detection Pump (LDP). LDP is located near passenger's side front corner of engine compartment. (Scheme 112) Apply a continuous vacuum supply of about 20 in. Hg to vacuum supply nipple on LDP. An A/C recovery unit works well for supplying a continuous vacuum supply. Turn ignition on. Using scan tool, select ENGINE SYSTEM TESTS, then LEAK DETECTION PUMP TEST. Read instructions on scan tool and then press ENTER. Select #3 HOLD PSI. Set EVAP system testing kit PRESSURE/HOLD valve to OPEN position and set VENT valve to CLOSED position. While monitoring EVAP system testing kit pressure gauge, turn EVAP system testing kit pump timer on. When pressure gauge reaches 14 in. H2O, turn PRESSURE HOLD valve to CLOSED position. Turn timer off. and wait 10 seconds. Note time and pressure. If pressure drops more than 6 in. H2O in 2 minutes, go to next step. If pressure drops 6 in. H2O or less in 2 minutes, go to step 4.
3. EVAP system pressure pump self-test should still be running. If DRB has timed out, restart EVAP system pressure pump self-test. Set EVAP system testing kit PRESSURE/HOLD valve to OPEN position. Set VENT valve to CLOSED position. Turn EVAP system testing kit pump timer on. To prevent noise from interfering with test, move EVAP system kit pressure gauge away from vehicle. Using Ultrasonic Leak Detector (6904A), check for leaks at gas cap, rollover valves, EVAP canisters, LDP and EVAP purge solenoid. Rollover valve(s) is located on top of fuel tank next to fuel pump module. Rollover valve(s) is not serviceable. If rollover valve(s) is defective, fuel tank must be replaced. Two EVAP canisters are located on outside of passenger's frame rail, directly below rear of the cab. Leak test all EVAP system hoses, tubes and connections. Repair or replace leaking component(s) as necessary. If no leaks exist, no problem is indicated at this time. Test is complete.
4. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Using scan tool, review FREEZE FRAME data. Attempt to duplicate condition that caused DTC to set. Thoroughly perform a visual inspection of EVAP system hoses, tubes and connections. Look for any physical damage or signs of wetness at connections. Visually inspect related connectors and wiring harness for damage. Check for any related technical service bulletins that may apply. Turn ignition on. Using scan tool in SYSTEM TESTS, perform LDP monitor test. This will force the PCM to run LDP monitor. If monitor fails, further diagnosis is required to find faulty component. If monitor passes, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0443 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0443 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect EVAP purge solenoid connector. EVAP purge solenoid may be located on firewall, near brake booster or near passenger's side front corner of engine compartment. (Scheme 112) Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, measure resistance between EVAP purge solenoid terminals. If resistance is 30-40 ohms, go to next step. If resistance is not 30-40 ohms, replace EVAP purge solenoid.
3. Turn ignition on. Measure voltage between ground and terminal No. 2 (Dark Blue/White wire) at EVAP purge solenoid harness connector. see scheme 12 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Dark Blue/White wire between fuse No. 11 (15-amp) and EVAP purge solenoid. Fuse No. 11 is located in junction block on end of driver's side of instrument panel, near door opening. Ensure fuse No. 11 is good.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Pink/White wire between terminal No. 1 at EVAP purge solenoid harness connector and terminal No. 20 at PCM C3 harness connector. see scheme 12and see scheme 21. If resistance is 5 ohms or more, repair open in Pink/White wire. If resistance is less than 5 ohms, go to next step.
5. Measure resistance between ground and terminal No. 1 (Pink/White wire) at EVAP purge solenoid wiring harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Pink/White wire between PCM and EVAP purge solenoid.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Using scan tool, review FREEZE FRAME data. Attempt to duplicate condition that caused DTC to set. Visually inspect related connectors and wiring harness for damage. Check for any related technical service bulletins that may apply. Ensure ignition is on, with engine off. Using scan tool, read and then clear DTCs. Using scan tool, actuate EVAP PURGE SOLENOID. Wiggle wiring harness from EVAP purge solenoid to PCM. EVAP purge solenoid may be located on firewall, near brake booster or near passenger's side front corner of engine compartment. (Scheme 112) PCM is located in right rear corner of engine compartment. see scheme 2 If EVAP purge solenoid DTC returns while wiggling wiring harness, repair wiring harness where wiggling caused DTC to return. If EVAP purge solenoid DTC does not return while wiggling wiring harness, no problem is indicated at this time. Test is complete.

1. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-97638-S14707392262001051000000) . Remove fuel tank. See FUEL TANK under FUEL SYSTEMS in appropriate REMOVAL, OVERHAUL & INSTALLATION article. Remove fuel pump module from fuel tank. Fuel pump module is located on top of fuel tank and contains fuel level sensor, fuel pump and fuel supply line fitting. Inspect fuel tank for damage or obstructions which would cause problems with operation of fuel level sensor. If fuel tank is not damaged or obstructed, replace fuel level sensor. If fuel tank is damaged or obstructed, repair or replace fuel tank as necessary.

1. Turn ignition on. Using scan tool, read fuel level sensor voltage. If fuel level sensor voltage is less than.4 volt, go to next step. If fuel level sensor voltage is.4 volt or more, go to step 5.
2. Turn ignition off. Disconnect fuel pump module connector. Fuel pump module is located on top of fuel tank and contains fuel level sensor along with fuel supply line fitting. Fuel pump module may also be referred to as fuel tank module. Turn ignition on. Using scan tool, read fuel level sensor voltage. If fuel level sensor voltage is 9 volts or less, go to next step. If fuel level sensor voltage is more than 9 volts, replace fuel level sensor. Fuel level sensor is located on fuel pump module.
3. Turn ignition off. Ensure fuel pump module is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between terminals No. 1 (Black wire) and No. 3 (Dark Blue/White wire) at fuel pump module harness connector. see scheme 14 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Black and Dark Blue/White wires are shorted together. Repair wiring as necessary. Black wire goes from fuel level sensor to ground connection located at driver's side front corner of engine compartment, on inner fender panel, near windshield washer fluid reservoir. Dark Blue/White wire goes from fuel pump module to PCM. This is the fuel level sensor signal wire.
4. Ensure fuel pump module connector and PCM connectors are still disconnected. Measure resistance between ground and No. 3 (Dark Blue/White wire) at fuel pump module harness connector. If resistance is 5 ohms or more, replace PCM. If resistance is less than 5 ohms, short to ground in Dark Blue/White wire between PCM and fuel pump module.
5. Turn ignition off. Using scan tool, monitor fuel level sensor voltage while wiggling wiring harness and connectors between fuel pump module connector on fuel pump module and PCM. Fuel pump module is located on top of fuel tank and contains fuel level sending unit along with fuel supply line fitting. Fuel pump module may also be referred to as fuel tank module. PCM is located in right rear corner of engine compartment. see scheme 2 If fuel level sensor voltage does not change while wiggling wiring harness and connectors, go to next step. If fuel level sensor voltage changes while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
6. Turn ignition off. Inspect wiring harness and connectors between fuel pump module and PCM. If no problems exist, test is complete. If any problems exist, repair wiring or connectors as necessary.

1. Turn ignition on. Using scan tool, read fuel level sensor voltage. If fuel level sensor voltage is more than 9.4 volts, go to next step. If fuel level sensor voltage is 9.4 volts or less, go to step 5.
2. Turn ignition off. Disconnect fuel pump module connector. Fuel pump module is located on top of fuel tank and contains fuel level sensor along with fuel supply line fitting. Fuel pump module may also be referred to as fuel tank module. Connect a jumper wire between terminals No. 1 (Black wire) and No. 3 (Dark Blue/White wire) at fuel pump module harness connector. see scheme 14 Turn ignition on. Using scan tool, read fuel level sensor voltage. If fuel level sensor voltage is one volt or more, go to next step. If fuel level sensor voltage is less than one volt, replace fuel level sensor.
3. Turn ignition off. Disconnect jumper wire from terminal No. 1 (Black wire) at fuel pump module harness connector and reconnect jumper wire to a good ground. Ensure other end of jumper wire is still connected to terminal No. 3 (Dark Blue/White wire) at fuel pump module harness connector. Turn ignition on. Using scan tool, read fuel level sensor voltage. If fuel level sensor voltage is one volt or more, remove jumper wire. Go to next step. If fuel level sensor voltage is less than one volt, repair open in Black wire between fuel pump module and ground connection. Ground connection is located at driver's side front corner of engine compartment, on inner fender panel, near windshield washer fluid reservoir.
4. Turn ignition off. Ensure fuel pump module is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Blue/White wire between terminal No. 3 at fuel pump module harness connector and terminal No. 26 at PCM C3 harness connector. see scheme 14and see scheme 21. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in Dark Blue/White wire.
5. Ensure ignition is on. Using scan tool, monitor fuel level sensor voltage while wiggling wiring harness and connectors between fuel pump module connector on fuel pump module and PCM. Fuel pump module is located on top of fuel tank and contains fuel level sending unit along with fuel supply line fitting. Fuel pump module may also be referred to as fuel tank module. PCM is located in right rear corner of engine compartment. see scheme 2 If fuel level sensor voltage does not change while wiggling wiring harness and connectors, go to next step. If fuel level sensor voltage changes while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
6. Turn ignition off. Inspect wiring harness and connectors between fuel pump module and PCM. If no problems exist, test is complete. If any problems exist, repair wiring or connectors as necessary.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0505 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0505 or displayed count is not "0", go to step 17.
2. Turn ignition off. Disconnect IAC motor connector. IAC motor is mounted on throttle body and contains a 4-pin connector. Start engine and allow engine to idle. Measure voltage between ground and terminal No. 1 (Gray/Red wire) at IAC motor harness connector. see scheme 15 If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step 15.
3. With engine still idling, measure voltage between ground at terminal No. 2 (Yellow/Black wire) at IAC motor harness connector. If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step 13.
4. With engine still idling, measure voltage between ground and terminal No. 3 (Brown/White wire) at IAC motor harness connector. If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step 11.
5. With engine still idling, measure voltage between ground and terminal No. 4 (Violet/Black wire) at IAC motor harness connector. If voltage is more than 5 volts at any time, go to next step. If voltage is not more than 5 volts at any time, go to step 9.
6. Turn ignition off. Disconnect PCM connectors. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between terminal No. 1 (Gray/Red wire) and each remaining terminal at IAC harness connector. If all resistance readings are 5 ohms or more, go to next step. If any resistance reading is less than 5 ohms, Gray/Red wire is shorted to wire with resistance less than 5 ohms. Repair wiring as necessary.
7. Measure resistance between terminal No. 2 (Yellow/Black wire) and terminals No. 3 (Brown/White wire) and No. 4 (Violet/Black wire) at IAC motor harness connector. If both resistance readings are 5 ohms or more, go to next step. If any resistance reading is less than 5 ohms, Yellow/Black wire is shorted to wire with resistance less than 5 ohms. Repair wiring as necessary.
8. Measure resistance between terminals No. 3 (Brown/White wire) and No. 4 (Violet/Black wire) at IAC motor harness connector. If resistance is 5 ohms or more, circuit is okay. Replace IAC motor. If resistance is less than 5 ohms, Brown/White and Violet/Black wires are shorted together. Repair wiring as necessary.
9. Turn ignition off. Ensure IAC motor is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Violet/Black wire between terminal No. 4 at IAC motor harness connector and terminal No. 20 at PCM C1 harness connector. see scheme 15and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/Black wire.
10. Measure resistance between ground and terminal No. 4 (Violet/Black wire) at IAC harness connector. If resistance is 5 ohms or more, replace PCM. If resistance is less than 5 ohms, repair short to ground in Violet/Black wire between IAC motor and PCM.
11. Turn ignition off. Ensure IAC motor is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 3 (Brown/White wire) at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Brown/White wire between IAC motor and PCM.
12. Measure resistance of Brown/White wire between terminal No. 3 at IAC motor harness connector and terminal No. 11 at PCM C1 harness connector. see scheme 15and see scheme 21. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in Brown/White wire.
13. Turn ignition off. Ensure IAC motor is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 2 (Yellow/Black wire) at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Yellow/Black wire between IAC motor and PCM.
14. Measure resistance of Yellow/Black wire between terminal No. 2 at IAC motor harness connector and terminal No. 10 at PCM C1 harness connector. see scheme 15and see scheme 21. If resistance is less than 5 ohms, circuit is okay. Replace PCM. If resistance is 5 ohms or more, repair open in Yellow/Black wire between IAC motor and PCM.
15. Turn ignition off. Ensure IAC motor is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 1 (Gray/Red wire) at IAC motor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Gray/Red wire between IAC motor and PCM.
16. Measure resistance of Gray/Red wire between terminal No. 1 at IAC motor harness connector and terminal No. 19 at PCM C1 harness connector. If resistance is less than 5 ohms, circuit is okay. Replace PCM. If resistance is 5 ohms or more, repair open in Gray/Red wire.
17. Start engine and allow engine to idle. Using scan tool in SYSTEM TESTS, perform IAC WIGGLE test. Wiggle wiring harness and connectors between IAC motor and PCM while observing operation of IAC motor. IAC motor is mounted on throttle body and contains a 4-pin connector. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 If IAC motor does not stop operating while wiggling wiring harness and connectors, go to next step. If IAC motor stops operating while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
18. Turn ignition off. Inspect wiring harness and connectors between IAC motor and PCM. If no problems exist, test is complete. If any problems exist, repair wiring or connectors as necessary.

1. Turn ignition on. Using scan tool, actuate GENERATOR FIELD DRIVER. Using a test light connected to ground, probe terminal No. 1 (Dark Green wire) on 2-wire connector at rear of generator with connector installed. If test light flashes on and off, go to next step. If test light does not flash on and off, go to step 3.
2. Ensure ignition is on and generator field driver is still actuated. Wiggle wiring harness and connectors between PCM and 2-wire connector on rear of generator. PCM is located in right rear corner of engine compartment. see scheme 2 Using scan tool, check for DTCs. If DTC P0622: GENERATOR FIELD NOT SWITCHING PROPERLY does not exist, no problem is indicated at this time. Test is complete. If DTC P0622: GENERATOR FIELD NOT SWITCHING PROPERLY exists, repair wiring harness or connector that caused DTC to return.
3. Stop actuation of generator field driver. Ensure ignition is on. Using scan tool, check for DTCs. Record all DTCs and FREEZE FRAME data. Using scan tool, clear DTCs from PCM. Turn ignition off. Inspect PCM connectors and 2-wire connector at rear of generator for corroded, damaged or pushed-out terminals. Clean and/or repair connectors as necessary. Go to next step.
4. Turn ignition on. Using scan tool, actuate GENERATOR FIELD DRIVER. Measure voltage between ground and terminal No. 2 (Dark Blue wire) on 2-wire connector at rear of generator. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Dark Blue wire between generator and PCM.
5. Stop actuation of generator field driver. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Disconnect 2-wire connector at rear of generator. Measure resistance between ground and terminal No. 10 (Dark Green wire) at PCM C2 harness connector. see scheme 21 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire between PCM and generator.
6. Measure resistance of Dark Green wire between terminal No. 10 at PCM C2 harness connector and terminal No. 1 on 2-wire connector at rear of generator. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green wire.
7. Measure resistance between both generator field driver terminals on back of generator. If resistance is less than 5 ohms, repair or replace generator. If resistance is 5 ohms or more, replace PCM.

1. Turn ignition on. Using scan tool, actuate A/C clutch relay. Listen for clicking sound at A/C clutch relay. The A/C clutch relay is located in Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 2 If clicking sound is heard at A/C clutch relay, go to next step. If clicking sound is not heard at A/C clutch relay, go to step 4.
2. Ensure ignition is still on and A/C clutch relay is still actuated by the scan tool. Wiggle wiring harness and connectors between A/C clutch relay and PCM while A/C clutch relay is still actuated. PCM is located in right rear corner of engine compartment. see scheme 2 If clicking sound at A/C clutch relay was not interrupted while wiggling wiring harness and connectors, go to next step. If clicking sound at A/C clutch relay was interrupted while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
3. Turn ignition off. Inspect PCM connectors for corroded, pushed out or damaged terminals. Inspect wiring harness and connectors between A/C clutch relay and PCM for chafed, pierced or partially broken wires. If terminals are not corroded, pushed out or damaged and wiring is okay, check for technical service bulletins that may apply. If terminals are corroded, pushed out or damaged, or wiring is damaged, repair as necessary.
4. Turn ignition off. Remove A/C clutch relay from PDC. see scheme 36 Turn ignition on. Measure voltage between ground and terminal No. 86 at A/C clutch relay socket in PDC. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open between ignition switch, fuse No. 11 (10-amp) and terminal No. 86 in PDC for A/C clutch relay. Fuse No. 11 is located in junction block on end of driver's side of instrument panel, near door opening.
5. Turn ignition off. Measure resistance between A/C clutch relay terminals No. 85 and 86. (Scheme 113) If resistance is 50-90 ohms, go to next step. If resistance is not 50-90 ohms, replace A/C clutch relay.
6. Ensure ignition is off and A/C clutch relay is still removed from PDC. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Blue/Orange wire between ground and terminal No. 1 at PCM C3 harness connector and terminal No. 85 at A/C clutch relay socket in PDC. see scheme 21and see scheme 36. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Blue/Orange wire.
7. Measure resistance between ground and terminal No. 85 (Dark Blue/Orange wire) in PDC. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Orange wire between PDC and PCM.
8. At this time, PCM is assumed to be defective. Replace PCM.

Scheme 113

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1195 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1195 is not displayed or displayed count is not "0", go to step 14.
2. Ensure ignition is on. Using scan tool in SENSOR mode, monitor 1/1 HO2S voltage until voltage stabilizes. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for 3 minutes. If voltage changes to less than 1.5 volts, go to next step. If voltage does not change to less than 1.5 volts, go to step 7.
3. Start engine and allow it to idle. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
4. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 1/1 HO2S. See «1/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S06057150842001060600000) table. If engine mechanical condition is okay, go to next step.
5. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 1/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/1 HO2S ground circuit (Black/Light Blue wire).
6. Turn ignition off. Using a voltmeter, backprobe Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) between 1/1 HO2S harness connector and terminal No. 24 at PCM C1 harness connector. Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to step 13. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/1 HO2S signal circuit (Black/Dark Green wire or Tan/White wire).
7. Turn ignition off. Disconnect 1/1 HO2S connector. Turn ignition on. Using scan tool, actuate O2 HEATER TEST. Measure voltage between ground and Dark Green/White wire at 1/1 HO2S harness connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in power circuit (Dark Green/White wire) to 1/1 HO2S heater. See WIRING DIAGRAMS.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/Violet wire between 1/1 HO2S harness connector and terminal No. 8 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Violet wire.
9. Turn ignition off. Using a voltmeter, backprobe Black/Dark Green wire (5.9L heavy-duty and 8.0L) or Tan/White wire (3.9L, 5.2L and 5.9L light-duty) between 1/1 HO2S harness connector and terminal No. 24 at PCM C1 harness connector. Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/1 HO2S signal circuit (Black/Dark Green wire or Tan/White wire).
10. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 1/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/1 HO2S ground circuit (Black/Light Blue wire).
11. Ensure engine is still idling. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
12. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 1/1 HO2S. If engine mechanical condition is okay, go to next step.
13. At this time, 1/1 HO2S is assumed to be defective. Replace 1/1 HO2S.
14. Start engine and allow it to idle. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
15. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 1/1 HO2S. If engine mechanical condition is okay, go to next step.
16. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, reconnect all connectors. Start engine. Wiggle related connectors and wiring harness while monitoring scan tool display. If GOOD TRIP counter display count changes to "0", repair connector or wiring harness where wiggling caused display to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Check for any related technical service bulletins that may apply.

1/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1196 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1196 is not displayed or displayed count is not "0", go to step 14.
2. Ensure ignition is on. Using scan tool in SENSOR mode, monitor 2/1 HO2S voltage until voltage stabilizes. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for 3 minutes. If voltage changes to less than 1.5 volts, go to next step. If voltage does not change to less than 1.5 volts, go to step 7.
3. Start engine and allow it to idle. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
4. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 2/1 HO2S. See «2/1 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S09023834192001060600000) table. If engine mechanical condition is okay, go to next step.
5. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 2/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 2/1 HO2S ground circuit (Black/Light Blue wire).
6. Turn ignition off. Using a voltmeter, backprobe Light Green/Red wire between 2/1 HO2S harness connector and terminal No. 26 at PCM C1 harness connector. Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to step 13. If voltage is.1 volt or more, repair poor connection causing high resistance in 2/1 HO2S signal circuit (Light Green/Red wire).
7. Turn ignition off. Disconnect 2/1 HO2S connector. Turn ignition on. Using scan tool, actuate O2 HEATER TEST. Measure voltage between ground and Dark Green/White wire at 2/1 HO2S harness connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in power circuit (Dark Green/White wire) to 2/1 HO2S heater. See WIRING DIAGRAMS.
8. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between 2/1 HO2S harness connector and terminal No. 16 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/White wire.
9. Turn ignition off. Using a voltmeter, backprobe Light Green/Red wire between 2/1 HO2S harness connector and terminal No. 26 at PCM C1 harness connector. Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 2/1 HO2S signal circuit (Light Green/Red wire).
10. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 2/1 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 2/1 HO2S ground circuit (Black/Light Blue wire).
11. Ensure engine is still idling. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
12. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 2/1 HO2S. If engine mechanical condition is okay, go to next step.
13. At this time, 2/1 HO2S is assumed to be defective. Replace 2/1 HO2S.
14. Start engine and allow it to idle. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
15. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 2/1 HO2S. If engine mechanical condition is okay, go to next step.
16. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, reconnect all connectors. Start engine. Wiggle related connectors and wiring harness while monitoring scan tool display. If GOOD TRIP counter display count changes to "0", repair connector or wiring harness where wiggling caused display to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Check for any related technical service bulletins that may apply.

2/1 HEATED OXYGEN SENSOR LOCATION

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1197 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1197 is not displayed or displayed count is not "0", go to step 14.
2. Ensure ignition is on. Using scan tool in SENSOR mode, monitor 1/2 HO2S voltage until voltage stabilizes. Using scan tool, actuate HO2S HEATER TEST and monitor 1/2 HO2S voltage for 3 minutes. If voltage changes to less than 1.5 volts, go to next step. If voltage does not change to less than 1.5 volts, go to step 7.
3. Start engine and allow it to idle. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
4. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 1/2 HO2S. See «1/2 HEATED OXYGEN SENSOR LOCATION»(ref-97638-S26884328882001060600000) table. If engine mechanical condition is okay, go to next step.
5. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 1/2 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/2 HO2S ground circuit (Black/Light Blue wire).
6. Turn ignition off. On 3.9L, 5.2L and 5.9L light-duty, using a voltmeter, backprobe Orange/Black wire between 1/2 HO2S harness connector and terminal No. 25 at PCM C1 harness connector. On 8.0L Calif., using a voltmeter, backprobe Tan/White wire between 1/2 HO2S harness connector and terminal No. 29 at PCM C1 harness connector. On all models, start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to step 13. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/2 HO2S signal circuit (Orange/Black wire or Tan/White wire).
7. Turn ignition off. Disconnect 1/2 HO2S connector. Turn ignition on. Using scan tool, actuate O2 HEATER TEST. Measure voltage between ground and terminal No. 1 at 1/2 HO2S harness connector. See «1/2 HEATED OXYGEN SENSOR HARNESS CONNECTOR TERMINAL IDENTIFICATION»(ref-97638-S35658291292001060600000) table. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in power circuit (Dark Green/Yellow or Dark Green/White wire) to 1/2 HO2S heater. See WIRING DIAGRAMS.
8. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 1/2 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/2 HO2S ground circuit (Black/Light Blue wire).
9. Turn ignition off. On 3.9L, 5.2L and 5.9L light-duty, using a voltmeter, backprobe Orange/Black wire between 1/2 HO2S harness connector and terminal No. 25 at PCM C1 harness connector. On 8.0L Calif., using a voltmeter, backprobe Tan/White wire between 1/2 HO2S harness connector and terminal No. 29 at PCM C1 harness connector. On all models, start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/2 HO2S signal circuit (Orange/Black wire or Tan/White wire).
10. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 1/2 HO2S harness connector and terminal No. 4 at PCM C1 harness connector. Start engine and ensure engine is at normal operating temperature. If voltage is less than.1 volt, go to next step. If voltage is.1 volt or more, repair poor connection causing high resistance in 1/2 HO2S ground circuit (Black/Light Blue wire).
11. Ensure engine is still idling. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
12. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 1/2 HO2S. If engine mechanical condition is okay, go to next step.
13. At this time, 1/2 HO2S is assumed to be defective. Replace 1/2 HO2S.
14. Start engine and allow it to idle. Check exhaust system for leaks between engine and catalytic converter. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
15. Ensure engine is still idling. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace 1/2 HO2S. If engine mechanical condition is okay, go to next step.
16. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, reconnect all connectors. Start engine. Wiggle related connectors and wiring harness while monitoring scan tool display. If GOOD TRIP counter display count changes to "0", repair connector or wiring harness where wiggling caused display to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Check for any related technical service bulletins that may apply.

1/2 HEATED OXYGEN SENSOR LOCATION

1/2 HEATED OXYGEN SENSOR HARNESS CONNECTOR TERMINAL IDENTIFICATION

1. The best way to diagnose this DTC is to allow the vehicle to sit overnight so that engine is cold. Check coolant level. If proper coolant level exists, go to next step. If proper coolant level does not exist, top off coolant level as needed.
2. Start engine and allow it to idle. Using scan tool, set engine speed to 1500 RPM and allow engine to warm up for 10-15 minutes. Using scan tool, monitor ENG COOLANT TMP DEG value during warm up period. If scan tool does not read at least 176°F (80°C), check thermostat and cooling system for probable causes. Repair cooling system as necessary. If scan tool reads at least 176°F (80°C), no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, actuate fuel pump relay. Listen for clicking sound at fuel pump relay. Fuel pump relay is located in Power Distribution Center (PDC). see scheme 36 PDC is located on left side of engine compartment. If clicking sound is heard at fuel pump relay, go to next step. If clicking sound is not heard at fuel pump relay, go to step 4.
2. Ensure ignition is still on and fuel pump relay is still actuated by the scan tool. Wiggle wiring harness and connectors between fuel pump relay and PCM while fuel pump relay is still actuated. PCM is located in right rear corner of engine compartment. see scheme 2 If clicking sound at fuel pump relay was not interrupted while wiggling wiring harness and connectors, go to next step. If clicking sound at fuel pump relay was interrupted while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
3. Turn ignition off. Inspect wiring harness and connectors between fuel pump relay and PCM. If no problems exist, test is complete. If any problems exist, repair wiring or connectors as necessary.
4. Turn ignition off. Remove fuel pump relay from PDC. Turn ignition on. Measure voltage between ground and terminal No. 86 (Light Green/Black wire) at fuel pump relay socket in PDC. see scheme 36 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open between ignition switch, fuse No. 9 (10-amp) and terminal No. 86 in PDC for fuel pump relay. Fuse No. 9 is located in junction block on end of driver's side of instrument panel, near door opening.
5. Turn ignition off. Measure resistance between fuel pump relay terminals No. 85 and 86. (Scheme 113) If resistance is 50-90 ohms, go to next step. If resistance is not 50-90 ohms, replace fuel pump relay.
6. Ensure ignition is off and fuel pump relay is still removed from PDC. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Brown/White wire between ground and terminal No. 19 at PCM C3 harness connector and terminal No. 85 at fuel pump relay socket in PDC. see scheme 21and see scheme 36. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/White wire.
7. Measure resistance between ground and terminal No. 19 (Brown/White wire) at PCM C3 harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Brown/White wire between PCM and PDC.
8. At this time, PCM is assumed to be defective. Replace PCM.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1294 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1294 is not displayed or displayed count is not "0", no problem is indicated at this time. Test is complete.
2. Turn ignition off. Check throttle linkage and throttle plate in throttle body for binding condition. With throttle linkage at idle position, ensure throttle plate is fully closed against stop. If no binding condition exists and throttle plate fully closes, go to next step. If binding condition exists or throttle plate does not fully close, repair as necessary.
3. Check engine vacuum hoses, brake booster and components for vacuum leaks. Ensure Closed Crankcase Ventilation (CCV) system (8.0L) or Positive Crankcase Ventilation (PCV) system (3.9L, 5.2L and 5.9L,) is functioning properly. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. Repair vacuum leaks as necessary. If CCV system or PCV system is okay and no vacuum leaks exist, go to next step.
4. On 3.9L, 5.2L and 5.9L, go to next step. On 8.0L, go to step 7.
5. Disconnect vacuum hose from PCV valve. Install.185" fixed orifice Air Metering Fitting (6714) on end of disconnected vacuum hose in place of PCV valve. Disconnect purge vacuum hose from passenger's side of throttle body. (Scheme 114) Install cap on purge vacuum hose fitting on throttle body.
6. Start engine and allow engine to idle. Warm engine to normal operating temperature. Using scan tool, actuate minimum airflow and note engine speed. Minimum airflow may also be referred to as throttle body minimum airflow. If engine speed is not 500-900 RPM, turn ignition off. Go to step 8. If engine speed is 500-900 RPM, turn ignition off. Remove air metering fitting and reconnect PCV valve. Test is complete.
7. Check that fixed orifice fitting is not restricted. Fixed orifice fitting is located on passenger's side of engine, directly behind ignition coils. (Scheme 115) If fixed orifice fitting is not restricted, go to next step. If fixed orifice fitting is restricted, clean as necessary and recheck idle. If idle is still incorrect, go to next step.
8. On all models, remove throttle body. With throttle fully open on throttle body, clean throttle body with parts cleaner. Using soft brush or pad, ensure throttle body bore and throttle plate are clean. Dry throttle body with compressed air. Reinstall throttle body.
9. On 3.9L, 5.2L and 5.9L, go to next step. On 8.0L, start engine and recheck idle. If idle is correct, test is complete. If idle is not correct, replace throttle body.
10. On 3.9L, 5.2L and 5.9L, start engine and allow engine to idle. Using scan tool, actuate minimum airflow and note engine speed. If engine speed is not 500-900 RPM, replace throttle body. If engine speed is 500-900 RPM, test is complete.

Scheme 114

Scheme 115

Note. If DTC P0107 is also present with DTC P1296, repair DTC P0107 before continuing with this test. See DTC P0107: MAP SENSOR VOLTAGE TOO LOW .

1. Turn ignition on. Using scan tool, read Manifold Absolute Pressure (MAP) sensor voltage. If voltage is less than 2.35 volts, go to next step. If voltage is 2.35 volts or more, go to step 6.
2. Turn ignition off. Disconnect MAP sensor connector. On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. see scheme 40 On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. see scheme 41 On all models, inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector terminals are okay, turn ignition on. Measure voltage between ground and Violet/White wire at MAP sensor harness connector. If voltage is more than 4.5 volts, go to next step. If voltage is 4.5 volts or less, repair 5-volt supply circuit (Violet/White wire) between MAP sensor and PCM.
3. Using scan tool, read MAP sensor voltage. If voltage is 4.5 volts or less, go to next step. If voltage is more than 4.5 volts, replace MAP sensor.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Violet/White wire at MAP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in 5-volt supply circuit (Violet/White wire).
5. At this time, PCM is assumed to be defective. Replace PCM.
6. Start engine and allow it to idle. Wiggle connectors and wiring harness from MAP sensor to PCM while monitoring MAP sensor voltage. On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. see scheme 40 On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. see scheme 41 On all models, PCM is located in right rear corner of engine compartment. see scheme 2 If voltage changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused voltage to change. If voltage does not change, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, check for DTCs. If DTC P0107: MAP SENSOR VOLTAGE TOO LOW does not exist, go to next step. If DTC P0107: MAP SENSOR VOLTAGE TOO LOW exists, perform «DTC P0107: MAP SENSOR VOLTAGE TOO LOW»(ref-97638-S32003683762001051000000) test.
2. Using scan tool, clear DTCs from PCM. Start engine and allow engine to idle for at least 30 seconds. Using scan tool, check for DTCs. If DTC P1297: NO CHANGE IN MAP FROM START TO RUN exists, turn ignition off and go to next step. If DTC P1297: NO CHANGE IN MAP FROM START TO RUN does not exist, go to step 5.
3. Ensure ignition is off. Disconnect MAP sensor connector. On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. see scheme 40 On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. see scheme 41 On all models, disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Violet/White wire between MAP sensor harness connector and terminal No. 17 at PCM C1 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/White wire.
4. Remove MAP sensor. Inspect vacuum port on MAP sensor for restrictions. Inspect vacuum port on throttle body which provides vacuum to MAP sensor for restrictions. If no restrictions exist, replace MAP sensor. If restriction exists, remove restriction and reinstall MAP sensor.
5. Using scan tool, increase engine speed to 1500 RPM. Using scan tool, monitor MAP sensor voltage while wiggling wiring harness and connectors between PCM and MAP sensor. PCM is located in right rear corner of engine compartment. see scheme 2 On 3.9L, 5.2L and 5.9L, MAP sensor is located on side of throttle body. see scheme 40 On 8.0L, MAP sensor is mounted on intake manifold, just above throttle body. see scheme 41 On all models, if engine does not stall or MAP sensor voltage does not becomes erratic while wiggling wiring harness and connectors, go to next step. If engine stalls or MAP sensor voltage becomes erratic while wiggling wiring harness and connectors, repair wiring and connectors as necessary.
6. Allow engine to idle. Using scan tool, monitor MAP sensor vacuum while quickly opening and closing the throttle several times. If MAP sensor vacuum does not decrease rapidly to less than one in. Hg, go to next step. If MAP sensor vacuum decreases rapidly to less than one in. Hg, no problem is indicated at this time. Test is complete.
7. Turn ignition off. Remove MAP sensor. Inspect vacuum port on MAP sensor for restrictions. Inspect vacuum port on throttle body which provides vacuum to MAP sensor for restrictions. If no restrictions exist, replace MAP sensor. If restriction exists, remove restriction and reinstall MAP sensor.

Note. A large vacuum leak is most likely cause for DTC to set.

1. Check engine vacuum hoses, brake booster and components for vacuum leaks. Ensure Closed Crankcase Ventilation (CCV) system (8.0L) or Positive Crankcase Ventilation (PCV) system (3.9L, 5.2L and 5.9L,) is functioning properly. See EMISSION SYSTEMS & SUB-SYSTEMS in appropriate SYSTEM & COMPONENT TESTING article. Repair vacuum leaks as necessary. If CCV system or PCV system is okay and no vacuum leaks exist, go to next step
2. Turn ignition on. Using scan tool, monitor TP sensor voltage while slowly depressing throttle pedal from idle position to wide open throttle position. If voltage changes smoothly from about .8 volt to more than 3.5 volts, go to next step. If voltage does not change smoothly from about .8 volt to more than 3.5 volts, replace TP sensor.
3. Ensure ignition is on. Ensure throttle plate is fully closed against stop. Using scan tool, read TP sensor voltage. If voltage is less than 1.5 volts, go to next step. If voltage is 1.5 volts or more, check throttle plate and linkage for binding. Repair throttle plate and linkage as necessary. If throttle plate and linkage are okay, replace TP sensor.
4. Turn ignition off. Connect a vacuum gauge to manifold vacuum source. Start engine and allow it to idle. If engine will not idle, maintain a constant RPM. Using scan tool in SENSOR mode, monitor Manifold Absolute Pressure (MAP) vacuum value. Compare scan tool reading with vacuum gauge reading. If scan tool reading is within one in. Hg of vacuum gauge, go to next step. If scan tool reading is not within one in. Hg of vacuum gauge reading, replace MAP sensor.
5. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1388 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1388 is not displayed or displayed count is not "0", go to step 6.
2. Turn ignition off. Remove ASD relay from Power Distribution Center (PDC). see scheme 36 PDC is located on left side of engine compartment. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Blue/Yellow wire between terminal No. 85 at ASD relay socket in PDC and terminal No. 3 at PCM C3 harness connector. see scheme 21and see scheme 36. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Dark Blue/Yellow wire.
3. Measure voltage between ground and terminal No. 86 (Red/Light Blue wire) at ASD relay socket in PDC. see scheme 36 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Red/Light Blue wire between ASD relay, through joint connector No. 2 and PDC. Also check fuse No. 6 (30-amp) in PDC.
4. Ensure ignition is off, ASD relay is removed and PCM is still disconnected. Measure resistance between ground and terminal No. 3 (Dark Blue/Yellow wire) at PCM C3 harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Yellow wire between PCM and ASD relay.
5. Measure resistance between ASD relay terminals No. 85 and 86. (Scheme 113) If resistance is 50-80 ohms, relay is okay. Replace PCM. If resistance is not 50-80 ohms, replace ASD relay.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, check for any related technical service bulletins that may apply. Start engine and allow it to idle. Wiggle wiring harness from ASD relay to PCM. ASD relay is located in PDC. see scheme 36 PDC is located on left side of engine compartment. PCM is located in right rear corner of engine compartment. see scheme 2 If GOOD TRIP counter display count changes to "0" while wiggling wiring harness, repair wiring harness where wiggling caused display count to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1389 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1389 is not displayed or displayed count is not "0", go to step 8.
2. Attempt to start engine. If engine starts, go to next step. If engine does not start, go to step 5.
3. Turn ignition off. Remove ASD relay from Power Distribution Center (PDC). PDC is located on left side of engine compartment. see scheme 36 Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Green/Orange wire between terminal No. 87 at ASD relay socket in PDC and terminal No. 12 at PCM C3 harness connector. see scheme 21and see scheme 36. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Dark Green/Orange wire.
4. At this time PCM is assumed to be defective. Replace PCM.
5. Turn ignition off. Remove ASD relay from Power Distribution Center (PDC). see scheme 36 PDC is located on left side of engine compartment. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Dark Green/Orange wire between terminal No. 87 at ASD relay socket in PDC and terminal No. 12 at PCM C3 harness connector. see scheme 21and see scheme 36. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green/Orange wire.
6. Measure voltage between ground and terminal No. 30 (Red/Light Blue wire) at ASD relay socket in PDC. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Red/Light Blue wire between ASD relay, through joint connector No. 2 and PDC. Also check fuse No. 6 (30-amp) in PDC.
7. Ensure ignition is off. Install a known-good ASD relay. Attempt to start engine. If engine starts, replace original ASD relay. If engine still fails to start, problem is not in the ASD relay output circuit to PCM. Check for other possible problems that may cause a no-start condition. See appropriate TROUBLE SHOOTING - NO CODES article.
8. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, check for any related technical service bulletins that may apply. Start engine and allow it to idle. Wiggle wiring harness from ASD relay to PCM. ASD relay is located in PDC. see scheme 36 PDC is located on left side of engine compartment. PCM is located in right rear corner of engine compartment. see scheme 2 If GOOD TRIP counter display count changes to "0" while wiggling wiring harness, repair wiring harness where wiggling caused display count to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1391 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1391 is not displayed or displayed count is not "0", go to step 12.
2. Connect scan tool to DLC. Using scan tool in MISCELLANEOUS FUNCTIONS, choose SET SYNC. The SET SYNC will indicate position of distributor for fuel synchronization, not the ignition timing, as ignition timing is controlled by PCM. Follow instructions on scan tool and start engine. Warm engine to normal operating temperature and note display on scan tool with engine idling. If IN RANGE with zero degrees is displayed, go to next step. If a plus or minus number is displayed next to the degree number, distributor must be repositioned. Loosen distributor clamp retaining bolt. Rotate distributor until IN RANGE is displayed on scan tool. Continue rotating distributor until achieving as close to zero degrees as possible. Tighten distributor clamp bolt to 16 ft. lbs. (22 N.m).
3. Turn ignition off. Note location of CMP sensor inside distributor. see scheme 42 Using voltage measurement lead on oscilloscope and Probe (6801), backprobe terminal No. 1 (Tan/Yellow wire) on CMP harness connector. see scheme 5 Start engine and allow engine to idle. Observe CMP sensor voltage signals on oscilloscope. If any CMP sensor voltage signals are missing from oscilloscope pattern, go to next step. If no CMP sensor voltage signals are missing from oscilloscope pattern, go to step 6.
4. Turn ignition off. Disconnect CMP sensor connector and PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect CMP sensor connector and PCM connectors for corroded, pushed out, miswired or damaged terminals. Ensure CMP sensor connector has a tight fit. Inspect wiring harness between CMP sensor and PCM for any possible intermittent problems. Also, check for related technical service bulletins. If terminals are not corroded, pushed out or damaged, and wiring harness is okay, go to next step. If terminals are corroded, pushed out or damaged, or wiring harness is damaged, repair as necessary.
5. Remove CMP sensor from distributor. Inspect pulse ring for looseness or damage. Pulse ring is located in the distributor below CMP sensor. see scheme 42 If pulse ring is okay, replace CMP sensor. If pulse ring is loose or damaged, repair or replace pulse ring as necessary.
6. Turn ignition off. Note location of CKP sensor on passenger's side of engine, just above the flywheel. see scheme 43 Using voltage measurement lead on oscilloscope and probe, backprobe terminal No. 1 (Gray/Black wire) on CKP sensor harness connector. see scheme 9 Start engine and allow engine to idle. Observe CKP sensor voltage signals on oscilloscope. If any CKP sensor voltage signals are missing from oscilloscope pattern, go to next step. If no CKP sensor voltage signals are missing from oscilloscope pattern, go to step 9.
7. Turn ignition. Disconnect CKP sensor connector and PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect CKP sensor connector and PCM connectors for corroded, pushed out, miswired or damaged terminals. Ensure CKP sensor connector has a tight fit. Inspect wiring harness between CKP sensor and PCM for any possible intermittent problems. Also, check for related technical service bulletins. If terminals are not corroded, pushed out or damaged and wiring harness is okay, go to next step. If terminals are corroded, pushed out or damaged, or wiring harness is damaged, repair as necessary.
8. Turn ignition off. Remove CKP sensor. On 3.9L, inspect the 3 sets of double notches and 3 sets of single notches at outer edge of flexplate/flywheel for damage/debris. On 5.2L and 5.9L, inspect the 8 individual notches spaced every 45 degrees at outer edge of flexplate/flywheel for damage/debris. On all models, these notches cause a pulse to be generated when they pass under the CKP sensor. If notches are okay, replace CKP sensor. If notched areas are damaged or debris exists, repair or replace flexplate/flywheel as necessary.
9. Turn ignition off. Disconnect CKP sensor connector and PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect CKP sensor connector and PCM connectors for corroded, pushed out, miswired or damaged terminals. Ensure CKP sensor connector has a tight fit. Inspect wiring harness between CKP sensor and PCM for any possible intermittent problems. Ensure CKP sensor is properly installed and retaining bolts are tightened to 70 INCH lbs. (7.9 N.m). Also, check for related technical service bulletins. If terminals are not corroded, pushed out or damaged, wiring harness is okay and CKP sensor is properly installed, reinstall connectors as necessary and go to next step. If terminals are corroded, pushed out or damaged, wiring harness is damaged or CKP sensor is not properly installed, repair as necessary.
10. Ensure ignition is off. Using voltage measurement lead on oscilloscope and probe, backprobe terminal No. 8 (Gray/Black wire) at PCM C1 harness connector. see scheme 21 Start engine and allow engine to idle. Observe CKP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CKP sensor. If no irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, go to next step. If irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
11. Turn ignition off. Using voltage measurement lead on oscilloscope and probe, backprobe terminal No. 18 (Tan/Yellow wire) at PCM C1 harness connector. Start engine and allow engine to idle. Observe CMP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CMP sensor. If no irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, test is complete. If irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
12. Turn ignition off. Using voltage measurement lead on oscilloscope and Probe (6801), backprobe terminal No. 18 (Tan/Yellow wire) at PCM C1 harness connector. PCM is located in right rear corner of engine compartment. see scheme 2 Start engine and allow engine to idle. Observe CMP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CMP sensor. CMP sensor is located inside distributor. see scheme 42 If no irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, go to next step. If irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, inspect wiring harness and connectors between PCM and CMP sensor. If wiring harness or connectors are defective, repair as necessary. If wiring harness and connectors are okay, replace CMP sensor.
13. Turn ignition off. Disconnect CMP sensor connector and PCM connectors. Inspect CMP sensor connector and PCM connectors for corroded, pushed out, miswired or damaged terminals. Inspect wiring harness between CMP sensor and PCM for any possible intermittent problems. Also, check for related technical service bulletins. If terminals are not corroded, pushed out or damaged and wiring harness is okay, reinstall connectors and go to next step. If terminals are corroded, pushed out or damaged, or wiring harness is damaged, repair as necessary.
14. Ensure ignition is off. Using oscilloscope lead and probe, backprobe terminal No. 8 (Gray/Black wire) at PCM C1 harness connector. Start engine and allow engine to idle. Observe CKP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CKP sensor. CKP sensor is located passenger's side of engine, just above the flywheel. see scheme 43 If no irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, test is complete. If irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, repair wiring or connectors as necessary.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1391 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1391 is not displayed or displayed count is not "0", go to step 14.
2. Ensure ignition is off. Note location of CMP sensor on timing chain cover at driver's side of engine. see scheme 44 Using voltage measurement lead on oscilloscope, backprobe terminal No. 1 (Tan/Yellow wire) at CMP harness connector. see scheme 5 Start engine and allow engine to idle. Observe CMP sensor voltage signals on oscilloscope. If any CMP sensor voltage signals are missing from oscilloscope pattern, go to next step. If no CMP sensor voltage signals are missing from oscilloscope pattern, go to step 6.
3. Check that CKP sensor is properly installed and retaining bolt is tightened to 70 INCH lbs. (7.9 N.m). CKP sensor is located on passenger's side of cylinder block. see scheme 45 Check that CMP sensor is properly installed and retaining bolt is tightened to 50 INCH lbs. (6.0 N.m). If CKP sensor or CMP sensor is not properly installed or retaining bolt is not tightened to specification, repair as necessary. If CKP and CMP sensors are properly installed and retaining bolts are tightened to specification, check connectors for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair connectors as necessary.
4. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect PCM connectors for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair connectors as necessary.
5. Remove CMP sensor and inspect camshaft sprocket. If camshaft sprocket is okay, replace CMP sensor. If camshaft sprocket is defective, replace camshaft sprocket.
6. Turn ignition off. Note location of CKP sensor on passenger's side of cylinder block. see scheme 45 Using voltage measurement lead on oscilloscope, backprobe terminal No. 1 (Gray/Black wire) at CKP sensor harness connector. Start engine and allow engine to idle. Observe CKP sensor voltage signals on oscilloscope. If any CKP sensor voltage signals are missing from oscilloscope pattern, go to next step. If no CKP sensor voltage signals are missing from oscilloscope pattern, go to step 11.
7. Turn ignition off. Disconnect CKP sensor connector. Inspect CKP sensor connector for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair connector as necessary.
8. Ensure ignition is off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Inspect PCM connectors for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair connectors as necessary.
9. Check that CKP sensor is properly installed and retaining bolt is tightened to 70 INCH lbs. (7.9 N.m). If CKP sensor is properly installed and retaining bolt is tightened to specification, go to next step. If CKP sensor is not properly installed or retaining bolt is not tightened to specification, repair as necessary.
10. Remove CKP sensor and inspect the 5 sets of double notches on the crankshaft counterweight for damage/debris. These notches cause a pulse to be generated when they pass under the CKP sensor. If notched areas are damaged or debris exists, repair or replace crankshaft as necessary. If notched areas are okay, replace CKP sensor.
11. Check that CKP sensor is properly installed and retaining bolt is tightened to 70 INCH lbs. (7.9 N.m). Check that CMP sensor is properly installed and retaining bolt is tightened to 50 INCH lbs. (6.0 N.m). If CKP sensor or CMP sensor is not properly installed or retaining bolt is not tightened to specification, repair as necessary. If CKP and CMP sensors are properly installed and retaining bolts are tightened to specification, check connectors for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair connectors as necessary.
12. Turn ignition. Using voltage measurement lead on oscilloscope, backprobe terminal No. 8 (Gray/Black wire) at PCM C1 harness connector. see scheme 21 PCM is located in right rear corner of engine compartment. see scheme 2 Start engine and allow engine to idle. Observe CKP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CKP sensor. If no irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, go to next step. If irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
13. Turn ignition off. Using voltage measurement lead on oscilloscope, backprobe terminal No. 18 (Tan/Yellow wire) at PCM C1 harness connector. Start engine and allow engine to idle. Observe CMP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CMP sensor. If no irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, test is complete. If irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, repair wiring or connectors as necessary.
14. Turn ignition off. Using voltage measurement lead on oscilloscope, backprobe terminal No. 18 (Tan/Yellow wire) at PCM C1 harness connector. Start engine and allow engine to idle. Observe CMP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CMP sensor. If no irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, go to next step. If irregularities exist in CMP sensor voltage signals while wiggling wiring harness and connectors, inspect wiring harness and connectors between PCM and CMP sensor. If wiring harness or connectors are defective, repair as necessary. If wiring harness and connectors are okay, replace CMP sensor.
15. Turn ignition off. Disconnect CMP sensor connector and PCM connectors. Inspect CMP sensor connector and PCM connectors for corroded, pushed out, miswired or damaged terminals. Inspect wiring harness between CMP sensor and PCM for any possible intermittent problems. Also, check for related technical service bulletins. If terminals are not corroded, pushed out or damaged and wiring harness is okay, reinstall connectors and go to next step. If terminals are corroded, pushed out or damaged, or wiring harness is damaged, repair as necessary.
16. Ensure ignition is off. Using oscilloscope lead and probe, backprobe terminal No. 8 (Gray/Black wire) at PCM C1 harness connector. Start engine and allow engine to idle. Observe CKP sensor voltage signals on oscilloscope while wiggling wiring harness and connectors between PCM and CKP sensor. CKP sensor is located passenger's side of engine, just above the flywheel. see scheme 43 If no irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, test is complete. If irregularities exist in CKP sensor voltage signals while wiggling wiring harness and connectors, inspect wiring harness and connectors between PCM and CKP sensor. If wiring harness or connectors are defective, repair as necessary. If wiring harness and connectors are okay, replace CKP sensor.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is not displayed for DTC P1398 or displayed count is not "0", go to step 4. If GOOD TRIP counter is displayed for DTC P1398 and displayed count is "0", go to next step.
2. Turn ignition off. Disconnect CKP sensor connector. On 3.9L, 5.2L and 5.9L, CKP sensor is located on passenger's side of engine, just above the flywheel. see scheme 43 On 8.0L, CKP sensor is located on passenger's side of cylinder block. see scheme 45 On all models, inspect CKP sensor connector for corroded, pushed out, miswired or damaged terminals. If terminals are not corroded, pushed out, miswired or damaged, go to next step. If terminals are corroded, pushed out, miswired or damaged, repair connector as necessary.
3. Check that CKP sensor is properly installed and retaining bolt(s) are tightened to 70 INCH lbs. (7.9 N.m). If CKP sensor is properly installed and retaining bolt(s) are tightened to specification, go step 6. If CKP sensor is not properly installed or retaining bolt(s) are not tightened to specification, repair as necessary.
4. Using scan tool, read and record FREEZE FRAME data. Pay particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Turn ignition on. Using scan tool in MISCELLANEOUS menu, select CLEAR PCM (battery disconnect) to reset PCM. Using scan tool, select MISFIRE PRETEST screen. Road test vehicle to allow relearn of adaptive numerator. Adaptive numerator is learned when ADAPTIVE NUMERATOR DONE LEARNING line on MISFIRE PRETEST screen changes to YES. If adaptive numerator relearned, go to next step. If adaptive numerator did not relearn, go to step 6.
5. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, monitor parameters related to DTC while wiggling connectors and wiring harness. If value changes while wiggling connectors and wiring harness, repair connectors and wiring harness where wiggling caused value to change. If value does not change, review FREEZE FRAME data using scan tool. Attempt to duplicate condition that caused DTC to set. Check for any related technical service bulletins that may apply. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. See WIRING DIAGRAMS article. If no problems are indicated, test is complete.
6. Remove crankshaft position sensor. On 3.9L, 5.2L and 5.9L, go to next step. On 8.0L, go to step 8.
7. On 3.9L, 5.2L and 5.9L, inspect flywheel for damage or misalignment. On 3.9L, inspect the 3 sets of double notches and 3 sets of single notches at outer edge of flexplate/flywheel for damage/debris. On 5.2L and 5.9L, inspect the 8 individual notches spaced every 45 degrees at outer edge of flexplate/flywheel for damage/debris. On all models, these notches cause a pulse to be generated when they pass under the CKP sensor. If notches are okay, replace CKP sensor. If notched areas are damaged or debris exists, repair or replace flexplate/flywheel.
8. On 8.0L, inspect the 5 sets of double notches on the crankshaft counterweight for damage/debris. These notches cause a pulse to be generated when they pass under the CKP sensor. If notches are okay, replace CKP sensor. If notched areas are damaged or debris exists, repair or replace crankshaft as necessary.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1486 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P1486 or displayed count is not "0", go to step 6.
2. To test EVAP system properly, fuel tank should have 20-80 percent of fuel capacity. Miller Evaporative System Testing Kit (6872A) and Gas Cap Adapter (8382) are used to perform evaporative system pressure test. Connect scan tool to Data Link Connector (DLC). Connect EVAP system testing kit positive lead to positive battery terminal and negative lead to negative battery terminal. Using EVAP system testing kit, and instructions printed on EVAP system testing kit cover, perform EVAP system pressure pump self-test. Remove gas cap and install gas cap adapter to fuel tank. Install gas cap to gas cap adapter. Connect pressure supply hose from evaporative system testing kit to fitting on gas cap adapter. Disconnect vacuum supply hose at Leak Detection Pump (LDP). LDP is located near passenger's side front corner of engine compartment. see scheme 46 Apply a continuous vacuum supply of about 20 in. Hg to vacuum supply nipple on LDP. An A/C recovery unit works well for supplying a continuous vacuum supply. Turn ignition on. Using scan tool, select ENGINE SYSTEM TESTS, then LEAK DETECTION PUMP TEST. Read instructions on scan tool and then press ENTER. Select #3 HOLD PSI. Set EVAP system testing kit PRESSURE/HOLD valve to OPEN position and set VENT valve to CLOSED position. While monitoring EVAP system testing kit pressure gauge, turn EVAP system testing kit pump timer on. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED position. Turn pump timer off. Disconnect fuel tank-to-EVAP canister purge hose (at EVAP canister) while monitoring gauge on evaporative system testing kit. EVAP canisters are located on outside of passenger's frame rail, directly below rear of the cab. If pressure decreases when purge hose is disconnected, go to next step. If pressure does not decrease when purge hose is disconnected, repair obstruction in EVAP system between EVAP canister and fuel tank.
3. Reconnect purge hose to EVAP canister. With engine still running and pump timer turned on, allow evaporative system to repressurize. Ensure PRESSURE/HOLD valve on evaporative system testing kit is set to OPEN position and VENT valve is set to CLOSED position. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED position. Turn pump timer off. Disconnect LDP pressure hose (at EVAP canister) that connects EVAP canister to LDP while monitoring gauge on evaporative system testing kit. If pressure decreases when hose is disconnected, go to next step. If pressure does not decrease when hose is disconnected, replace EVAP canisters.
4. Reconnect LDP pressure hose. With engine still running and pump timer turned on, allow evaporative system testing kit to repressurize. Ensure PRESSURE/HOLD valve on evaporative system testing kit is set to OPEN position and VENT valve is set to CLOSED position. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED position. Turn pump timer off. Disconnect EVAP purge solenoid hoses while monitoring gauge on evaporative system testing kit. EVAP purge solenoid may be located on firewall, near brake booster or near passenger's side front corner of engine compartment. see scheme 46 If pressure does not decrease when hoses are disconnected from EVAP purge solenoid, repair or replace hose/tubes to EVAP purge solenoid as necessary. If pressure decreases when vacuum hoses are disconnected from EVAP purge solenoid, go to next step.
5. Inspect pressure hose between EVAP canister and LDP. If pressure hose is okay and is not restricted, replace LDP. If pressure hose is defective or restricted, replace pressure hose.
6. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Using scan tool, review FREEZE FRAME data. Attempt to duplicate condition that caused DTC to set. Thoroughly perform a visual inspection of EVAP system hoses, tubes and connections. Look for any physical damage or signs of wetness at connections. Visually inspect related connectors and wiring harness for damage. Check for any related technical service bulletins that may apply. Turn ignition on. Using scan tool in SYSTEM TESTS, perform LDP monitor test. This will force the PCM to run LDP monitor. If monitor fails, further diagnosis is required to find faulty component. If monitor passes, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1492 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P1492 is not displayed or displayed count is not "0", go to step 6.
2. Turn ignition off. Disconnect BTS connector located on battery tray, below battery. BTS connector contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. Measure resistance between ground and terminal No. 1 (Black/Light Blue wire) at BTS harness connector. see scheme 4 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Light Blue wire between BTS and PCM. PCM is located in right rear corner of engine compartment. see scheme 2
3. Turn ignition off. Ensure BTS is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Pink/Yellow wire between terminal No. 2 at BTS harness connector and terminal No. 15 at PCM C3 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Pink/Yellow wire.
4. Ensure BTS is still disconnected. Start engine and allow engine to idle. Measure voltage between ground and terminal No. 2 (Pink/Yellow wire) at BTS harness connector. If voltage is 5.5 volts or less, go to next step. If voltage is more than 5.5 volts, repair short to voltage in Pink/Yellow wire between BTS and PCM.
5. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Using scan tool in SENSORS mode, read AMBIENT/BAT TMP VLT (BTS voltage). Connect a jumper wire between terminals No. 1 (Black/Light Blue wire) and No. 2 (Pink/Yellow wire) at BTS harness connector. If BTS voltage changed from more than 4.5 volts to less than one volt, replace BTS. If BTS voltage did not change from more than 4.5 volts to less than one volt, replace PCM.
6. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, reconnect all connectors. Start engine. Wiggle BTS connector and wiring harness while monitoring scan tool display. If GOOD TRIP counter display count changes to "0", repair connector or wiring harness where wiggling caused display to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Check for any related technical service bulletins that may apply.

1. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1493 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P1493 or displayed count is not "0", go to step 5.
2. Using scan tool in SENSORS mode, read AMBIENT/BAT TMP VLT (BTS voltage). Disconnect BTS connector located on battery tray, below battery. BTS connector contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. If BTS voltage did not change from less than one volt to more than 4.5 volts, go to next step. If BTS voltage changed from less than one volt to more than 4.5 volts, replace BTS.
3. Turn ignition off. Ensure BTS is still disconnected. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 2 (Pink/Yellow wire) on BTS harness connector. see scheme 4 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Pink/Yellow wire between PCM and BTS.
4. Measure resistance between terminals No. 1 (Black/Light Blue wire) and No. 2 (Pink/Yellow wire) at BTS harness connector. If resistance is 5 ohms or more, replace PCM. If resistance is less than 5 ohms, Pink/Yellow and Black/Light Blue wires are shorted together. Repair wiring as necessary.
5. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, reconnect all connectors. Start engine. Wiggle BTS connector and wiring harness while monitoring scan tool display. If GOOD TRIP counter display count changes to "0", repair connector or wiring harness where wiggling caused display to change. If GOOD TRIP counter display count does not change to "0", no problem is indicated at this time. Check for any related technical service bulletins that may apply.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1494 and displayed count is "0", go next step. If GOOD TRIP counter is not displayed for DTC P1494 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect engine vacuum supply hose at Leak Detection Pump (LDP). LDP is located near passenger's side front corner of engine compartment. see scheme 46 Connect vacuum gauge to disconnected engine vacuum supply hose. Start engine and note vacuum reading. If vacuum at engine vacuum supply hose is at least 13 in. Hg, turn ignition off. Remove vacuum gauge, reinstall engine vacuum supply hose and go to next step. If vacuum at engine vacuum supply hose is not at least 13 in. Hg, turn ignition off. Remove vacuum gauge and repair leak or obstruction on engine vacuum supply hose to LDP.
3. Ensure ignition is off. Disconnect LDP connector. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance of Orange wire between terminal No. 4 at LDP harness connector and terminal No. 14 at PCM C3 harness connector. see scheme 20and see scheme 21. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open on Orange wire.
4. Turn ignition on. Using scan tool in INPUTS/OUTPUTS mode, monitor LDP switch state while connecting jumper wire between positive battery terminal and terminal No. 4 (Orange wire) at LDP harness connector. If LDP switch state does not change, remove jumper wire and go to next step. If LDP switch state changes, replace LDP.
5. Measure resistance between ground and terminal No. 14 (Orange wire) at PCM C3 harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Orange wire between LDP and PCM.
6. At this time PCM is assumed to be defective. Replace PCM.
7. At this time, conditions for LDP fault does not exist. Ensure ignition is on. Using scan tool, actuate LEAK DETECTION PUMP. Wiggle wiring harness and connectors between PCM and LDP while listening for LDP to stop operating and noting GOOD TRIP counter. PCM is located in right rear corner of engine compartment. see scheme 2 LDP is located near passenger's side front corner of engine compartment. see scheme 46 If LDP does not stop operating while wiggling wiring harness and connectors, and GOOD TRIP counter does not change to zero, go to next step. If LDP stops operating while wiggling wiring harness and connectors, or GOOD TRIP counter changes to zero, repair wiring or connectors between PCM and LDP as necessary.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P1495 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P1495 or displayed count is not "0", go to step 6.
2. Turn ignition off. Disconnect Leak Detection Pump (LDP) connector. LDP is located near passenger's side front corner of engine compartment. see scheme 46 Turn ignition on. Using scan tool, actuate LEAK DETECTION PUMP. Using a test light connected to ground, probe terminal No. 2 (Dark Blue wire) at LDP harness connector. see scheme 20 If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open in Dark Blue wire between LDP and PCM. PCM is located in right rear corner of engine compartment. see scheme 2
3. Using a test light connected to battery voltage, probe terminal No. 3 (White/Dark Green wire) at LDP harness connector. If test light does not flash on and off, stop leak detection pump activation and go to next step. If test light flashes on and off, replace LDP.
4. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Ensure LDP is still disconnected. Measure resistance between ground and terminal No. 3 (White/Dark Green wire) at LDP harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in White/Dark Green wire between LDP and PCM.
5. Measure resistance of White/Dark Green wire between terminal No. 3 at LDP harness connector and terminal No. 10 at PCM C3 harness connector. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair open in White/Dark Green wire.
6. At this time, conditions for LDP solenoid circuit malfunction do not exist. Turn ignition off. Inspect wiring harness and connectors between PCM and LDP. PCM is located in right rear corner of engine compartment. see scheme 2 LDP is located near passenger's side front corner of engine compartment. see scheme 46 If any problems exist, repair wiring or connectors as necessary. If no problems exist, turn ignition on. Using scan tool, actuate LEAK DETECTION PUMP. Wiggle wiring harness and connectors between PCM and LDP while listening for LDP to stop operating and noting GOOD TRIP counter. If LDP does not stop operating while wiggling wiring harness and connectors, and GOOD TRIP counter does not change to zero, no problem is indicated at this time. Test is complete. If LDP stops operating while wiggling wiring harness and connectors, or GOOD TRIP counter changes to zero, repair wiring or connectors between PCM and LDP as necessary.

1. Turn ignition on. Using scan tool, actuate generator field driver. Using a test light connected to ground, probe terminal No. 1 (Dark Green wire) at 2-wire connector at rear of generator. If test light blinks on and off, go to next step. If test light does not blink on and off, go to step 5.
2. Using scan tool, stop actuation of generator field driver. Ensure ignition is on. Using scan tool, read target charging voltage. If target charging voltage is more than zero volts, go to next step. If target charging voltage is zero volts, go to step 4.
3. Start engine and manually set engine speed to 1600 RPM. Using scan tool, read target charging voltage and battery voltage. Compare the 2 readings for 5 minutes. If voltage difference is not more than one volt, allow engine to return to idle. Turn ignition off. Test is complete. If difference between the 2 readings is more than one volt, replace PCM. PCM is located in right rear corner of engine compartment. see scheme 2
4. Ensure ignition is on. Using scan tool in INPUTS/OUTPUTS mode, read BTS temperature. BTS is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. Using a thermometer, measure underhood temperature near battery tray. If underhood temperature is within 10°F of BTS temperature, replace PCM. If underhood temperature is not within 10°F of temperature of battery temperature sensor, replace BTS.
5. Turn ignition off. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Disconnect 2-wire connector at rear of generator. Measure resistance between ground and terminal No. 10 (Dark Green wire) at PCM C2 harness connector. see scheme 21 If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire between generator and PCM.
6. Ensure 2-wire connector at rear of generator is still disconnected. Measure resistance between ground and generator field driver terminal on back of generator. This is the terminal on rear of generator that Dark Green wire in the round 2-wire connector fits on. If resistance is 5 ohms or more, replace PCM. If resistance is less than 5 ohms, short exists in the generator. Repair or replace generator as necessary.

1. Turn ignition on. Using scan tool in SENSORS mode, read speed control switch voltage. Speed control switch voltage may also be referred to as S/C switch voltage. If speed control switch voltage is less than one volt, go to next step. If speed control switch voltage is one volt or more, conditions required for DTC to be set are not present at this time. Test is complete.
2. Turn ignition off. Disconnect speed control on/off switch 2-pin connector at rear of speed control on/off switch assembly on steering wheel. Turn ignition on. Using scan tool in SENSORS mode, read speed control switch voltage. If speed control switch voltage does not change to 5 volts, go to next step. If speed control switch voltage changes to 5 volts, replace speed control on/off switch.
3. Turn ignition off. Disconnect speed control resume/accel switch 2-pin connector at rear of speed control resume/accel switch assembly on steering wheel. Turn ignition on. Using scan tool in SENSORS mode, read speed control switch voltage. If speed control switch voltage does not change to 5 volts, go to next step. If speed control switch voltage changes to 5 volts, replace speed control resume/accel switch.
4. Turn ignition off. Ensure speed control on/off and resume/accel switches connectors are still disconnected. Measure resistance between terminals No. 1 (White wire) and No. 2 (Dark Green/Red wires) at speed control on/off switch connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, White and Dark Green/Red wires are shorted together. Repair wiring as necessary. These wires go from speed control on/off and resume/accel switches, through clockspring and to PCM. PCM is located in right rear corner of engine compartment. see scheme 2
5. Ensure speed control on/off and resume/accel switches connectors are still disconnected. Disconnect clockspring C1 connector. see scheme 48 Measure resistance between ground and terminal No. 1 (Red/Light Green wire) at clockspring C1 harness connector. see scheme 6 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, go to step 7.
6. Disconnect PCM connectors. PCM is located in right rear corner of engine compartment. see scheme 2 Measure resistance between ground and terminal No. 1 (Red/Light Green wire) on clockspring C1 harness connector. If resistance is still less than 5 ohms, repair short to ground in Red/Light Green wire between PCM and clockspring. If resistance now 5 ohms or more, replace PCM.
7. Ensure speed control on/off and resume/accel switches connectors are still disconnected. Disconnect clockspring C2 connector. see scheme 48 Measure resistance between ground and terminal "A" (Dark Green/Red wire) at clockspring C2 harness connector. see scheme 7 If resistance is 5 ohms or more, replace clockspring. If resistance is less than 5 ohms, repair short to ground in Dark Green/Red wire between clockspring and speed control on/off and resume/accel switches.

1. Ensure battery is fully charged and generator drive belt is in good condition and properly adjusted before proceeding. Start engine and allow engine to idle. Using scan tool, read target charging voltage. If target charging voltage is more than 15.1 volts, go to next step. If target charging voltage is 15.1 volts or less, go to step 9.
2. Ensure engine is idling and at normal operating temperature. Using scan tool, read AMBIENT/BAT TMP DEG (BTS temperature). Using thermometer, measure underhood temperature near battery tray. If underhood temperature is not within 10°F of BTS temperature, go to next step. If underhood temperature is within 10°F of BTS temperature, go to step 9.
3. Turn ignition off. Disconnect BTS connector. BTS is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. Connect a jumper wire between BTS harness connectors terminals. Turn ignition on. Using scan tool, read AMBIENT/BAT VOLT (BTS voltage). If voltage is more than zero volts, go to next step. If voltage is zero volts, replace BTS.
4. Ensure ignition is on. Using scan tool, check for DTCs and record FREEZE FRAME data. Using scan tool, clear DTCs from PCM. Turn ignition off. Inspect PCM connectors, BTS connector and 2-wire connector at rear of generator for corroded, pushed out or damaged terminals. PCM is located in right rear corner of engine compartment. see scheme 2 If terminals are corroded, pushed out or damaged, repair as necessary. If terminals are not corroded, pushed out or damaged, reconnect all connectors. Backprobing, measure voltage at terminal No. 2 (Dark Blue wire) at 2-wire connector at rear of generator. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Dark Blue wire between generator and PCM.
5. Turn ignition off. Disconnect 2-wire connector at rear of generator. Disconnect PCM connectors. Measure resistance of Dark Green wire between terminal No. 1 at generator harness connector and terminal No. 10 at PCM C2 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green wire.
6. Measure resistance between ground and terminal No. 25 (Dark Blue wire) at PCM C3 harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue wire between PCM and 2-wire connector at rear of generator.
7. Measure resistance between ground and terminal No. 10 (Dark Green wire) at PCM C2 harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire between PCM and 2-wire connector at rear of generator.
8. Reconnect all connectors. Connect a voltmeter between generator case and negative battery post. Start engine and warm engine to normal operating temperature. Note voltage reading. If voltage is.1 volt or less, go to step 17. If voltage is more than.1 volt, repair generator for high resistance between generator case and negative battery post.
9. Turn ignition off. Connect a voltmeter between positive battery post and battery terminal on rear of generator. Start engine and warm engine to normal operating temperature. Note voltage reading. If voltage is.4 volt or less, go to next step. If voltage is more than.4 volt, repair high resistance between positive battery post and positive battery terminal on rear of generator.
10. Turn ignition off. Connect voltmeter between case of generator and negative battery post. Start engine and warm engine to normal operating temperature. Note voltage reading. If voltage is.1 volt or less, go to next step. If voltage is more than.1 volt, repair generator for high resistance between generator case and negative battery post.
11. Ensure engine is idling and at normal operating temperature. Turn on all accessories. Adjust engine speed to 1600 RPM. Using scan tool, read target charging voltage and charging voltage. Compare the 2 readings. If difference between the 2 readings is more than one volt, go to next step. If difference between the 2 readings is one volt or less, no problem is indicated at this time. Test is complete.
12. Turn engine off. Using scan tool, actuate GENERATOR FIELD DRIVER. Measure voltage between ground and each terminal in 2-wire connector at rear of generator. If voltage is less than 3 volts at either terminal, go to next step. If voltage is 3 volts or more at both terminals, charging system is operating properly at this time. Test is complete.
13. Ensure ignition is on. Using scan tool, check for DTCs and record FREEZE FRAME data. Using scan tool, clear DTCs from PCM. Turn ignition off. Inspect PCM connectors, BTS connector and 2-wire connector at rear of generator for corroded, pushed out or damaged terminals. BTS is located on battery tray, below battery and contains a 2-pin connector with Black/Light Blue and Pink/Yellow wires. PCM is located in right rear corner of engine compartment. see scheme 2 If terminals are corroded, pushed out or damaged, repair as necessary. If terminals are not corroded, pushed out or damaged, reconnect all connectors. Backprobing, measure voltage at terminal No. 2 (Dark Blue wire) at 2-wire connector on back of generator. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in Dark Blue wire between generator and PCM.
14. Turn ignition off. Disconnect 2-wire connector at rear of generator. Disconnect PCM connectors. Measure resistance between ground and terminal No. 10 (Dark Green wire) at PCM C2 harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Green wire between PCM and 2-wire connector at rear of generator.
15. Measure resistance of Dark Green wire between terminal No. 1 at generator harness connector and terminal No. 10 at PCM C2 harness connector. see scheme 21 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Green wire.
16. Measure resistance between ground and terminal No. 25 (Dark Blue wire) at PCM C3 harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue wire between PCM and 2-wire connector at rear of generator.
17. At this time PCM is assumed to be defective. Replace PCM.

1. Using scan tool, perform SRI memory test. If scan tool displays WRITE FAILURE, replace PCM. If scan tool does not display WRITE FAILURE, go to next step.
2. Using scan tool, perform SRI memory test again. If scan tool displays WRITE REFUSED, go to next step. If scan tool does not display WRITE REFUSED, go to step 4 .
3. Using scan tool, attempt SRI memory test 3 more times. If scan tool still displays WRITE REFUSED, replace PCM. If scan tool does not display WRITE REFUSED, test is complete.
4. Using scan tool, perform SRI memory test again. If scan tool displays SRI MILEAGE INVALID, update mileage and retest SRI memory. If scan tool does not display SRI MILEAGE INVALID, go to next step.
5. Compare SRI mileage stored with instrument panel odometer. If mileage is within specified range displayed on scan tool, test is complete. If mileage is not within specified range displayed on scan tool, update mileage and retest SRI memory.

FUEL SYSTEM/MISFIRE MONITOR VERIFICATION TEST

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If any DTCs have not been diagnosed, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If all DTCs have been diagnosed and repaired, go to next step.
2. Connect scan tool to Data Link Connector (DLC), if not previously done. Ensure fuel tank is at least 1/4 full. Ensure A/C is off. Go to next step.
3. If repair procedure did not include replacing PCM, or PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. See «PROGRAMMING»(ref-97638-S05891496752001051000000) . After PCM has been programmed, go to next step.
4. Ensure misfire detection is enabled if a misfire DTC was repaired. Low fuel level or an unlearned adaptive numerator can disable the misfire monitor. If PCM has been replaced or disconnected during testing, the adaptive numerator must be relearned in order for misfire monitor to run.
5. Using scan tool, monitor SIMILAR CONDITIONS and attempt to duplicate conditions during which vehicle was operating at when DTC was set. If conditions can be duplicated, GOOD TRIP counter will change to one or more. If conditions cannot be duplicated, clear DTCs. If OBD-II monitor failed after running, repair is not complete. Check for technical service bulletins that apply to symptom. Go to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom.
6. If repaired DTC has reset, proceed to appropriate DTC test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If monitor ran and GOOD TRIP counter changed to one or more, repair was successful and test is now complete.

POWERTRAIN VERIFICATION TEST VER-1

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine components are connected properly. Reassemble and reconnect components as necessary. If repair procedure did not include replacing PCM, go to next step. If PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. See «PROGRAMMING»(ref-97638-S05891496752001051000000) . After PCM is programmed, go to next step.
2. Inspect engine oil for fuel contamination. Change engine oil and filter as necessary. Attempt to start engine. If engine starts, go to next step. If engine does not start, go to appropriate TROUBLE SHOOTING - NO CODES article for additional testing. Also, refer to any technical service bulletins that may apply.
3. Run engine for one warm-up cycle to verify operation. Using scan tool, confirm that no DTCs or secondary indicators are present and that all components are functioning properly. If a DTC is present, repair is not complete. Perform appropriate test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If no DTCs are present, repair is complete.

POWERTRAIN VERIFICATION TEST VER-2

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If test is being performed after performing a repair that did not involve a Diagnostic Trouble Code (DTC) test, go to next step. If test is being performed after performing a repair that involved a DTC test, go to step 3 .
2. Check if initial symptom still exists. If initial or another symptom exists, repair is not complete. Check for technical service bulletins that apply to symptom. Go to appropriate TROUBLE SHOOTING - NO CODES article for diagnosis by symptom. If initial symptom no longer exists and no DTCs are present, test is complete.
3. If repair procedure did not include replacing PCM, or PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. See «PROGRAMMING»(ref-97638-S05891496752001051000000) . After PCM has been programmed, go to next step.
4. Road test vehicle for at least 5 minutes. If repair involved A/C relay control circuit, ensure A/C is on during road test. Road test vehicle at a speed of at least 40 MPH at some point during road test. Stop vehicle. Turn engine off for at least 10 seconds. Start engine and continue road test. Ensure transmission shifts through all gears. After road test, turn engine off and go to next step.
5. Using scan tool, read DTCs. If original DTC did not return and there are no new DTCs, test is complete. If original DTC returns or another DTC is present, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS.

POWERTRAIN VERIFICATION TEST VER-3

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If repair procedure did not include replacing PCM, or PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. See «PROGRAMMING»(ref-97638-S05891496752001051000000) . After PCM has been programmed, go to next step.
2. Ensure no other charging problems exist before continuing. Start engine. Ensure generator output voltage is okay. Raise engine speed to 2000 RPM for at least 30 seconds. Allow engine to idle. Turn ignition off.
3. Turn ignition on. Using scan tool, read DTCs. If original DTC did not return and there are no new DTCs, test is complete. If original DTC returns or another DTC is present, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS.

POWERTRAIN VERIFICATION TEST VER-4

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine and speed control system components are connected. Reassemble and reconnect components as necessary. Using scan tool, record and erase Diagnostic Trouble Codes (DTC) from PCM.
2. Road test vehicle at a speed greater than 35 MPH. Turn speed control switch on. Press and release SET switch and verify speed control engages. If speed control engages, go to next step. If speed control does not engage, go to step 11 .
3. With speed control engaged, depress and hold ACCEL switch. If vehicle speed increases, release switch and go to next step. If vehicle speed does not increase, go to step 11 .
4. Press and hold DECEL switch. If vehicle speed decreases, release switch and go to next step. If vehicle speed does not decrease, go to step 11 .
5. Depress and release CANCEL switch. If speed control disengages, go to next step. If speed control does not disengage, go to step 11 .
6. Decrease vehicle speed to less than 25 MPH and depress RESUME switch. If vehicle resumes previously set speed, go to next step. If vehicle does not resume previously set speed, go to step 11 .
7. Using caution, press and release brake pedal to activate brakelight switch. If speed control disengages, go to next step. If speed control does not disengage, go to step 11 .
8. Increase vehicle speed to more than 35 MPH. Press and release SET switch. If vehicle maintains new set speed, go to next step. If vehicle does not set or maintain a new set speed, go to step 11 .
9. Depress and release on/off switch to OFF position. If speed control disengages, go to next step. If speed control did not disengage, go to step 11 .
10. Using scan tool, check for DTCs. If no DTCs are present and vehicle is operating as designed, repair is complete. If DTCs exist, or system is not operating as designed, go to next step.
11. If original DTC returns or another DTC is present, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS.

POWERTRAIN VERIFICATION TEST VER-5

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If any DTCs have not been diagnosed, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If all DTCs have been diagnosed and repaired, go to next step.
2. Connect scan tool to Data Link Connector (DLC), if not previously done. Ensure fuel tank is at least 1/4 full. Ensure A/C is off. Go to next step.
3. If repair procedure did not include replacing PCM, go to next step. If PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. See «PROGRAMMING»(ref-97638-S05891496752001051000000) . After PCM has been programmed, go to next step.
4. Ensure all DTCs are cleared from PCM. Proper way to ensure DTC is properly repaired is to allow PCM to run the OBD-II monitor. OBD-II monitor operation may be observed on the scan tool. In order for OBD-II monitor to be run, certain pretest enabling conditions must be met. Refer to applicable OBD-II monitor pretest screen on scan tool for monitor enabling conditions.
5. Operate vehicle within enabling conditions and allow applicable OBD-II monitor to run. While OBD-II monitor is running, scan tool will beep and IN PROGRESS will be displayed on the OBD-II monitor screen. After OBD-II monitor is complete, view the results. OBD-II monitor may have to fail more than once in order for DTC to be stored in PCM. If OBD-II monitor fails, repaired DTC has reset, or any DTCs exist, repair is not complete. Check for related technical service bulletins and proceed to appropriate DTC test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If catalytic converter was replaced, select MISCELLANEOUS, then CATALYST REPLACED and press enter. If GOOD TRIP counter changed to one or more and no new DTCs exist, repair was successful and test is now complete.

POWERTRAIN VERIFICATION TEST VER-6

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If repair procedure did not include replacing PCM, go to next step. If PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. See «PROGRAMMING»(ref-97638-S05891496752001051000000) . After PCM has been programmed, go to next step.
2. If any DTCs have not been diagnosed, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If all DTCs have been diagnosed and repaired, go to next step.
3. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If any DTCs have not been diagnosed, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If all DTCs have been diagnosed and repaired, go to next step.
4. Connect scan tool to Data Link Connector (DLC), if not previously done. Ensure all accessories are off. Start engine and allow it to idle. Ensure shift lever is in Park and throttle is in idle position. Place scan tool in LDP DEALER TEST MODE and follow instructions as displayed on scan tool. If a DTC for a small leak is set, repair is not complete. Check for related technical service bulletins and return to diagnostic test from which you came. If any other DTC exists, perform appropriate diagnostic test(s). See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If all DTCs have been diagnosed and repaired, test is complete.

TRANSMISSION VERIFICATION TEST

Note. If replacing Powertrain Control Module (PCM), the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent Diagnostic Trouble Codes (DTC) from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM).

1. Inspect vehicle to ensure all engine components are connected. Reassemble and reconnect components as necessary. If any DTCs have not been diagnosed, perform appropriate diagnostic test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If all DTCs have been diagnosed and repaired, go to next step.
2. If repair procedure did not include replacing PCM, go to next step. If PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. See «PROGRAMMING»(ref-97638-S05891496752001051000000) . After PCM has been programmed, go to next step.
3. Using scan tool, clear PCM and TCM DTCs. Ensure transmission fluid is at proper level. Ensure fuel tank is at least 1/4 full and all accessories are off. Road test vehicle. Using scan tool, monitor engine RPM. Make 15-20 1st-2nd, 2nd-3rd and 3rd-4th upshifts. Perform shifts from a standing start to 45 MPH with a constant throttle opening of 20-25 degrees.
4. With vehicle speed less than 25 MPH, make 5-8 wide open throttle kickdowns to 1st gear. Allow at least 5 seconds each in 2nd and 3rd gear between each kickdown.
5. Using scan tool, monitor SIMILAR CONDITIONS and attempt to duplicate conditions during which vehicle was operating at when DTC was set. If conditions can be duplicated, GOOD TRIP counter will change to one or more. If repaired DTC resets, proceed to appropriate DTC test. See «DIAGNOSTIC TROUBLE CODE MESSAGES & CODES»(ref-97638-S19037405012001061100000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If conditions cannot be duplicated and GOOD TRIP counter changed to one or more, repair was successful and test is now complete.