Engine Controls Self-Diagnostics - Wrangler: Diagnosis Jeep Wrangler II

SELF-DIAGNOSTIC SYSTEM

Note. Self-diagnostic tests are written specifically for Chrysler's Diagnostic Readout Box (DRBIII(R)) 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. models. Vehicles from other states may be equipped with Calif. emissions. Models with Federal emissions may be referred to as Federal models. Check underhood label for application.

DIAGNOSTIC PROCEDURE

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

VISUAL INSPECTION

Most engine control system driveability problems 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. Diagnostic Trouble Codes (DTC) can only be retrieved by using a scan tool. See RETRIEVING DIAGNOSTIC TROUBLE CODES .

RETRIEVING DIAGNOSTIC TROUBLE CODES

Note. Ensure battery is fully charged before proceeding with Diagnostic Trouble Code (DTC) retrieval.

Scheme 26

Scheme 27

1. Turn ignition off. DTCs can only be retrieved using a scan tool. Connect scan tool to Data Link Connector (DLC) located below instrument panel, near steering column. (Scheme 26)Turn ignition on. Using scan tool manufacturer's instructions, read and record DTC (generic scan tool) or DTC message (DRBIII(R) scan tool), and freeze frame data.
2. If scan tool will not power up, check for loose cable connections or bad cable. If cable connections and cable are okay, measure voltage at DLC power terminal No. 16 (Pink/White wire). (Scheme 27) Voltage should be at least 11 volts. If voltage is not as specified, check wiring circuit and fuse No. 24 (10-amp) in Power Distribution Center (PDC). PDC is located in right side of engine compartment, next to battery. Repair wiring or replace fuse as necessary.
3. If scan tool displays USER-REQUESTED COLD BOOT error or USER-REQUESTED WARM BOOT error, or any other error message, record entire displayed error message and follow scan tool manufacturer's instructions.
4. 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 - WRANGLER article in ACCESSORIES & EQUIPMENT.
5. If any DTCs are displayed, perform appropriate diagnostic test. See «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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 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.

Using Scan Tool

Connect scan tool to Data Link Connector (DLC). DLC is located below instrument panel near steering column. (Scheme 26) Turn ignition on. Using screen prompts on scan tool, clear DTCs from Powertrain Control Module (PCM).

Self-Erasure

After 3 good trips, Powertrain Control Module (PCM) will turn off the MIL. At that time, the PCM will automatically switch the trip counter to a warm-up cycle counter. The PCM will erase DTCs after 40 warm-up cycles if the recent malfunction does not reoccur in that time. For additional information on good trips and warm-up cycles, see TRIP INDICATOR .

DIAGNOSTIC TROUBLE CODE DEFINITIONS

DTC MESSAGES & CODES

DIAGNOSTIC TESTS

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

Testing

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

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 on firewall in right rear corner of engine compartment. 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. Measure resistance between Orange/Dark Green and Brown/Orange wires at 1/1 HO2S connector (component side). If resistance is not 4-5 ohms with HO2S at 70°F (21°C), replace 1/1 HO2S. If resistance is 4-5 ohms, 1/1 HO2S heater element is okay. Go to next step.
4. Measure voltage between ground and Orange/Dark Green 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 power circuit to 1/1 HO2S heater. See WIRING DIAGRAMS.
5. Disconnect Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/Orange wire between 1/1 HO2S harness connector and terminal C8 at PCM C3 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Orange wire.
6. Measure voltage between ground and terminal C8 (Brown/Orange 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/Orange wire between 1/1 HO2S and PCM.
7. At this time, PCM is assumed to be defective. Replace PCM.

Scheme 28

Note. 1/2 HO2S may also be referred to as a downstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/2 HO2S is located behind catalytic converter.

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 on firewall in right rear corner of engine compartment. 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 Orange/Dark Green 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 Orange/Dark Green 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 power circuit to 1/2 HO2S heater. See WIRING DIAGRAMS.
5. Disconnect Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. 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 C16 at PCM C3 harness connector. (Scheme 28) 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 C16 (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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

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 on firewall in right rear corner of engine compartment. 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 Orange/Dark Green and Brown/White wires at 2/1 HO2S connector (component side). If resistance is not 4-5 ohms with HO2S at 70°F (21°C), replace 2/1 HO2S. If resistance is 4-5 ohms, 2/1 HO2S heater element is okay. Go to next step.
4. Measure voltage between ground and Orange/Dark Green 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 power circuit to 2/1 HO2S heater. See WIRING DIAGRAMS.
5. Disconnect Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. 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 C16 at PCM C3 harness connector. (Scheme 28) 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 C16 (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.

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. Using a voltmeter, backprobe Black/Light Blue wire between BTS harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine and note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 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 C15 at PCM C3 harness connector. (Scheme 28) Start engine and note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 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 Manifold Absolute Pressure (MAP) sensor voltage. If voltage is less than 1.2 volts, go to step 4. If voltage is 1.2 volts or more, go to next step.
2. Start engine and allow it to idle. Using scan tool, read MAP sensor voltage. If voltage is 0.04 volt or more, go to next step. If voltage is less than 0.04 volt, go to step 4.
3. At this time, conditions for MAP sensor low voltage do not exist or fault is an intermittent problem. Ensure engine is idling and at normal operating temperature. Using scan tool, monitor MAP sensor voltage while wiggling connectors and wiring harness from MAP sensor to Powertrain Control Module (PCM). (Scheme 29)or (Scheme 30). PCM is located on firewall in right rear corner of engine compartment. 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 MAP 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, test is complete.
4. Turn ignition off. Disconnect MAP sensor connector. (Scheme 29)or (Scheme 30). 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 Orange 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. 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. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, 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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Orange 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 Orange wire.
9. Measure resistance of Orange wire between MAP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
10. At this time, PCM is assumed to be defective. Replace PCM.

Scheme 29

Scheme 30

1. Start engine and allow it to idle. Using scan tool, read MAP 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 8.
2. Turn ignition off. Disconnect MAP sensor connector. (Scheme 29)or (Scheme 30). Disconnect Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between Orange and Dark Green/Red wires at MAP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange and Dark Green/Red 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, disconnect jumper wire and go to next step. If voltage is less than one volt, replace MAP sensor.
5. Turn ignition off. Disconnect PCM connectors. Measure resistance of Dark Green/Red wire between MAP sensor harness connector and terminal A27 at PCM C1 harness connector. (Scheme 28) 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 A4 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 Black/Light Blue wire.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. At this time, conditions for MAP sensor high voltage do not exist or fault is an intermittent problem. Ensure engine is idling and at normal operating temperature. Using scan tool, monitor MAP sensor voltage while wiggling connectors and wiring harness from MAP sensor to Powertrain Control Module (PCM). (Scheme 29)or (Scheme 30). PCM is located on firewall in right rear corner of engine compartment. 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 MAP 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, 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. (Scheme 29)or (Scheme 30). 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 IAT harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine and note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 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 IAT harness connector and terminal A15 at PCM C1 harness connector. (Scheme 28) Start engine and note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 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 Powertrain Control Module (PCM). (Scheme 29)or (Scheme 30). PCM is located on firewall in right rear corner of engine compartment. 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.

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 IAT sensor low voltage 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 Powertrain Control Module (PCM). (Scheme 29)or (Scheme 30). PCM is located on firewall in right rear corner of engine compartment. 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.
4. Turn ignition off. Disconnect IAT sensor connector. (Scheme 29)or (Scheme 30). 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 Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and 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, repair short to ground in Black/Red wire between PCM and IAT sensor.
6. Measure resistance between Black/Red and Black/Light Blue wires at IAT sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Black/Red and Black/Light Blue 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 IAT sensor low voltage do not exist or fault is an intermittent problem. Ensure engine is idling and at normal operating temperature. Using scan tool, monitor IAT sensor voltage while wiggling connectors and wiring harness from IAT sensor to Powertrain Control Module (PCM). (Scheme 29)or (Scheme 30). PCM is located on firewall in right rear corner of engine compartment. 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 be 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, 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 8.
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 8.
3. Turn ignition off. Disconnect IAT sensor connector. (Scheme 29)or (Scheme 30). 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 Black/Red wire at IAT sensor harness connector. If voltage is more than 5.5 volts, repair short to voltage in Black/Red wire between IAT sensor and PCM. If voltage is 5.5 volts or less, no problem is indicated at this time. Test is complete.
4. 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, IAT sensor circuits are okay. Replace IAT sensor.
5. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Black/Red wire between IAT sensor harness connector and terminal A15 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black/Red wire.
6. Measure resistance of Black/Light Blue wire between IAT sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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 IAT sensor high voltage 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 Powertrain Control Module (PCM). (Scheme 29)or (Scheme 30). PCM is located on firewall in right rear corner of engine compartment. 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, 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. (Scheme 31) 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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and 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, repair short to ground in Tan/Black wire between PCM and ECT sensor.
4. Measure resistance between Tan/Black and Black/Light Blue wires at ECT sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Tan/Black and Black/Light Blue 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 ECT sensor low voltage 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 ECT sensor voltage while wiggling connectors and wiring harness from ECT sensor to Powertrain Control Module (PCM). (Scheme 31) PCM is located on firewall in right rear corner of engine compartment. 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 ECT 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, test is complete.

Scheme 31

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0118 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0118 is not displayed or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect ECT sensor connector. (Scheme 31) Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Measure voltage between ground and Tan/Black wire at ECT 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 Tan/Black wire between ECT sensor and PCM.
3. Turn ignition off. Connect a jumper wire between Tan/Black and Black/Light Blue wires at ECT harness sensor connector. Turn ignition on. Using scan tool, read ECT sensor voltage. If voltage is one volt or more, disconnect jumper wire and go to next step. If voltage is less than one volt, replace ECT sensor.
4. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Tan/Black wire between ECT sensor harness connector and terminal A16 at PCM C1 harness connector. (Scheme 28) 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 ECT sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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 ECT sensor high voltage 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 ECT sensor voltage while wiggling connectors and wiring harness from ECT sensor to Powertrain Control Module (PCM). (Scheme 31) PCM is located on firewall in right rear corner of engine compartment. 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 ECT 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, test is complete.

Note. If DTC P0500 is present or if any other TP sensor or MAP sensor related DTC is present, repair those DTCs before continuing with this test. Ensure throttle plate and linkage are not binding and no carbon build-up is present on throttle plate. Repair throttle plate and linkage as necessary before continuing.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P0121 is displayed and displayed count is "0", go to next step. 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, read MAP sensor voltage. 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 0.8 volt to more than 3.5 volts, go to step 22. If voltage does not change smoothly from about 0.8 volt to more than 3.5 volts, go to next step.
4. Turn ignition off. Disconnect TP sensor connector. (Scheme 29)or (Scheme 30). Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Orange wire between TP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
5. Measure resistance between ground and Orange 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 wire between TP sensor and PCM.
6. Disconnect MAP sensor connector. (Scheme 29)or (Scheme 30). 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. Measure resistance of Black/Light Blue wire between MAP sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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. Reconnect MAP sensor and PCM connectors. Ensure TP sensor is disconnected. Turn ignition on. Using scan tool, read TP sensor voltage. Connect a jumper wire between Orange/Dark Blue and Black/Light Blue wires at TP sensor harness connector. Note TP sensor voltage reading. If TP sensor voltage changes from about 4.9 volts to less than 0.5 volt, replace TP sensor. If TP sensor voltage does not change from about 4.9 volts to less than 0.5 volt, go to next step.
9. Turn ignition off. Disconnect PCM connectors. Measure resistance of Orange/Dark Blue wire between TP sensor harness connector and terminal A23 at PCM C1 harness connector. (Scheme 28) 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 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.
11. Measure resistance of Black/Light Blue wire between TP sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open Black/Light Blue wire.
12. At this time, PCM is assumed to be defective. Replace PCM.
13. Turn ignition off. Disconnect MAP sensor connector. (Scheme 29)or (Scheme 30). Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Orange wire between MAP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
14. Measure resistance between ground and Orange 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 Orange wire between MAP sensor and PCM.
15. Turn ignition off. Disconnect TP sensor connector. (Scheme 29)or (Scheme 30). Measure resistance of Orange wire between TP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
16. Measure resistance between ground and Orange 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 wire between TP sensor and PCM.
17. Reconnect TP sensor and PCM connectors. Ensure MAP sensor is disconnected. Turn ignition on. Using scan tool, read MAP sensor voltage. Connect a jumper wire between Dark Green/Red and Black/Light Blue wires at MAP sensor harness connector. Note MAP sensor voltage reading. If MAP sensor voltage changes from about 4.9 volts to less than 0.5 volt, replace MAP sensor. If MAP sensor voltage does not change from about 4.9 volts to less than 0.5 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 A27 at PCM C1 harness connector. (Scheme 28) 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 between PCM and MAP sensor.
20. Measure resistance of Black/Light Blue wire between MAP sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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, fault does 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 TP sensor voltage while wiggling connectors and wiring harness from TP sensor to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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, repeat wiggle test for MAP sensor. Repair connectors and wiring harness as necessary. If no problem is indicated, use scan tool and review FREEZE FRAME data. Attempt to duplicate condition that caused DTC to set by paying special attention to the conditions during which TP sensor and MAP sensor are 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.

1. Turn ignition on. Using scan tool, read TP sensor voltage. If voltage is less than 0.2 volt, go to next step. If voltage is 0.2 volt or more, go to step 10.
2. Turn ignition off. Disconnect TP sensor connector. (Scheme 29)or (Scheme 30). Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Measure voltage between ground and Orange wire at TP sensor harness connector. If voltage is 4.5-5.5 volts, go to next step. If voltage is not 4.5-5.5 volts, go to step 7.
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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and 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 TP sensor and terminal A23 at PCM C1 connector. (Scheme 28)
5. Measure resistance between Black/Light Blue and Orange/Dark Blue wires at TP 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 Orange/Dark Blue wires are shorted together. Repair wiring as necessary. See WIRING DIAGRAMS article.
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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Orange 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 wire between TP sensor and PCM.
8. Measure resistance of Orange wire between TP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange 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 0.8 volt to more than 3.5 volts, go to next step. If voltage does not change smoothly from about 0.8 volt to more than 3.5 volts, replace TP sensor.
11. At this time, conditions for TP sensor low voltage 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 TP sensor voltage while wiggling connectors and wiring harness from TP sensor to Powertrain Control Module (PCM). (Scheme 29)or (Scheme 30). PCM is located on firewall in right rear corner of engine compartment. 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 TP 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, test is complete.

Note. Ensure throttle is fully closed and free from carbon build-up.

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, go to step 9.
2. Turn ignition off. Disconnect TP sensor connector. (Scheme 29)or (Scheme 30). Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between Orange/Dark Blue wire and Orange 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 Orange wires are shorted together. Repair wiring as necessary.
3. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on, with engine off. Measure voltage between ground and 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 between PCM and TP sensor.
4. Measure voltage between ground and Orange/Dark Blue wire at TP sensor harness connector. If voltage is still more than 5 volts, clockspring is shorted internally. Replace clockspring. See appropriate AIR BAG RESTRAINT SYSTEMS article in ACCESSORIES & EQUIPMENT. If voltage is not more than 5 volts, go to next step.
5. Turn ignition off. Connect a jumper wire between Black/Light Blue wire and Orange/Dark Blue wire at TP sensor harness connector. Turn ignition on. Using scan tool, read TP sensor voltage. If voltage is 0.5 volt or more, go to next step. If voltage is less than 0.5 volt, replace TP sensor.
6. Turn ignition off. Disconnect PCM connectors. Measure resistance of Black/Light Blue wire between TP sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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. Measure resistance of Orange/Dark Blue wire between TP sensor harness connector and terminal A23 at PCM C1 harness connector. (Scheme 28) 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.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. Ensure ignition is on. Using scan tool, monitor TP sensor voltage. Slowly open and close throttle plate while monitoring TP sensor voltage. If voltage changes smoothly from about 0.8 volt to more than 3.5 volts, go to next step. If voltage does not change smoothly from about 0.8 volt to more than 3.5 volts, replace TP sensor.
10. At this time, conditions for TP sensor high voltage 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 TP sensor voltage while wiggling connectors and wiring harness from TP sensor to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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 TP 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, 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. Turn ignition on. Using scan tool, read 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 6.
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 on firewall in right rear corner of engine compartment. 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. (Scheme 31) Visually inspect connector for corroded, damaged, pushed-out or miswired terminals. Repair connector as necessary. If connector is okay, replace ECT sensor.
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 ECT sensor 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.

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0131 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0131 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 0.16 volt, turn ignition off and go to next step. If voltage is 0.16 volt or more, go to step 8 .
3. Disconnect 1/1 HO2S connector. Start engine and allow it to idle. Using scan tool, read 1/1 HO2S voltage. If voltage is 0.16 volt or less, go to next step. If voltage is more than 0.16 volt, replace 1/1 HO2S.
4. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Measure resistance between ground and Black/Dark Green wire 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 between 1/1 HO2S and PCM.
5. Measure resistance between Black/Dark Green and Black/Light Blue wires 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/Dark Green and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. Measure resistance between Black/Dark Green and Brown/Orange wires 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/Dark Green and Brown/Orange 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 1/1 HO2S voltage while wiggling connectors and wiring harness from 1/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0132 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0132 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, turn ignition off go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Disconnect 1/1 HO2S connector. 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. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Turn ignition on. Measure voltage between ground and Black/Dark Green wire 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 between 1/1 HO2S and PCM.
5. Measure resistance between Black/Dark Green and Orange/Dark Green wires 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/Dark Green and Orange/Dark Green wires are shorted together. Repair wiring as necessary.
6. Measure resistance of Black/Dark Green wire between 1/1 HO2S harness connector and terminal A24 at PCM C1 harness connector. (Scheme 28) 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.
7. Measure resistance of Black/Light Blue wire between 1/1 HO2S harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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 1/1 HO2S voltage while wiggling connectors and wiring harness from 1/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

1. Turn ignition on. 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. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Turn engine off. Using a voltmeter, backprobe Black/Dark Green wire between 1/1 HO2S harness connector and terminal A24 at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine and allow it to idle for 4-5 minutes. Note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/1 HO2S signal circuit (Black/Dark Green wire) between 1/1 HO2S and PCM.
4. Using voltmeter, backprobe Black/Light Blue between 1/1 HO2S harness connector and terminal A4 at PCM C1 harness connector. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/1 HO2S ground circuit (Black/Light Blue wire) between 1/1 HO2S and PCM.
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 1/1 HO2S voltage while wiggling connectors and wiring harness from 1/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

1. Turn ignition on. Using scan tool, check for 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 and wait 8 minutes or more to allow HO2S to cool down. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for 2 minutes or more. If voltage stays at 0.4-0.6 volt, go to next step. If voltage does not stay at 0.4-0.6 volt, go to step 7.
3. Turn ignition off. Allow 1/1 HO2S to cool down to room temperature. Disconnect 1/1 HO2S connector. Measure resistance between Orange/Dark Green and Brown/Orange wires at 1/1 HO2S harness connector (component side). If resistance is not 4-5 ohms, replace 1/1 HO2S. If resistance is 4-5 ohms, 1/1 HO2S heater element is okay. Go to next step.
4. Ensure ignition is off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/Orange wire between 1/1 HO2S harness connector and terminal C8 at PCM C3 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Orange wire.
5. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Ensure 1/1 HO2S is still disconnected. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Orange/Dark Green 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 to 1/1 HO2S heater. See WIRING DIAGRAMS article.
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 1/1 HO2S voltage while wiggling connectors and wiring harness from 1/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 1/2 HO2S is located in front exhaust pipe below front mini-catalytic converter and may also be referred to as a downstream oxygen sensor.

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 No. 16 (10-amp) from Power Distribution Center (PDC) located in right side of engine compartment, next to battery. see scheme 3 If fuse is okay, go to step 4. If fuse is blown, go to next step.
3. Remove HO2S downstream heater relay from PDC. see scheme 3 Measure resistance between ground and terminal B11 (Orange/Dark Green wire) at HO2S downstream heater relay socket in PDC. see scheme 3 If resistance is 5 ohms or more, circuit is okay. Replace fuse. If resistance is less than 5 ohms, repair short to ground in Orange/Dark Green wire. Replace fuse.
4. Remove HO2S downstream heater relay from PDC. see scheme 3 Measure resistance between terminals No. 85 and 86 at downstream heater relay. (Scheme 32) If resistance is 100 ohms or less, go to next step. If resistance is more than 100 ohms, replace relay.
5. Measure resistance of Orange/Dark Green wire between terminal B11 at HO2S downstream heater relay socket in PDC and terminal No. 16 at fuse holder for fuse No. 16 in PDC. see scheme 3 If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange/Dark Green wire.
6. Ensure ignition is off. Disconnect Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. Measure resistance of Red/Yellow wire between terminal B15 at HO2S downstream heater relay socket in PDC and terminal C9 at PCM C3 harness connector. see scheme 3and (Scheme 28). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Red/Yellow wire.
7. Measure resistance between ground and terminal B15 (Red/Yellow wire) at HO2S downstream heater 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 Red/Yellow wire. See WIRING DIAGRAMS article.
8. At this time, PCM is assumed to be defective. Replace PCM.
9. It is assumed that there is an intermittent problem with wiring harness and/or connectors. Visually inspect all related connectors and wiring harness for any possible problems. Also, check for any related technical service bulletins.

Scheme 32

Note. 1/2 HO2S may also be referred to as a downstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/2 HO2S is located behind catalytic converter. On 4.0L Calif. models, 1/2 HO2S is 1ocated in front exhaust pipe below front mini-catalytic converter.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0137 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0137 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 0.16 volt, turn ignition off and go to next step. If voltage is 0.16 volt or more, go to step 8 .
3. Disconnect 1/2 HO2S connector. Start engine and allow it to idle. Using scan tool, read 1/2 HO2S voltage. If voltage is 0.16 volt or less, go to next step. If voltage is more than 0.16 volt, replace 1/2 HO2S.
4. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Measure resistance between ground and Tan/White wire at 1/2 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 Tan/White wire between 1/2 HO2S and PCM.
5. Measure resistance between Tan/White and Black/Light Blue wires at 1/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Tan/White and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. Measure resistance between Tan/White and Brown/Orange wires at 1/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Tan/White and Brown/Orange 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 1/2 HO2S voltage while wiggling connectors and wiring harness from 1/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 1/2 HO2S may also be referred to as a downstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/2 HO2S is located behind catalytic converter. On 4.0L Calif. models, 1/2 HO2S is located in front exhaust pipe below front mini-catalytic converter.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0138 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0138 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, turn ignition off go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Disconnect 1/2 HO2S connector. 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. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Turn ignition on. Measure voltage between ground and Tan/White wire at 1/2 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 Tan/White wire between 1/2 HO2S and PCM.
5. Measure resistance between Tan/White wire and Orange/Dark Green wire (except 4.0L Calif.) or Violet/Orange wire (4.0L Calif.) at 1/2 HO2S harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Tan/White wire and Orange/Dark Green wire (except 4.0L Calif.) or Violet/Orange wire (4.0L Calif.) are shorted together. Repair wiring as necessary.
6. Measure resistance of Tan/White wire between 1/2 HO2S harness connector and terminal A25 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Tan/White wire.
7. Measure resistance of Black/Light Blue wire between 1/2 HO2S harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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 1/2 HO2S voltage while wiggling connectors and wiring harness from 1/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 1/2 HO2S may also be referred to as a downstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/2 HO2S is located behind catalytic converter. On 4.0L Calif. models, 1/2 HO2S is located in front exhaust pipe below front mini-catalytic converter.

1. Turn ignition on. 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. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Turn engine off. Using a voltmeter, backprobe Tan/White wire between 1/2 HO2S harness connector and terminal A25 at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine and allow it to idle for 4-5 minutes. Note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/2 HO2S signal circuit (Tan/White wire) between 1/2 HO2S and PCM.
4. Using voltmeter, backprobe Black/Light Blue between 1/2 HO2S harness connector and terminal A4 at PCM C1 harness connector. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/2 HO2S ground circuit (Black/Light Blue wire) between 1/2 HO2S and PCM.
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 1/2 HO2S voltage while wiggling connectors and wiring harness from 1/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 1/2 HO2S may also be referred to as a downstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/2 HO2S is located behind catalytic converter. On 4.0L Calif. models, 1/2 HO2S is located in front exhaust pipe below front mini-catalytic converter.

1. Turn ignition on. Using scan tool, check for 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 and wait 8 minutes or more to allow HO2S to cool down. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST and monitor 1/2 HO2S voltage for 2 minutes or more. If voltage stays at 0.4-0.6 volt, go to next step. If voltage does not stay at 0.4-0.6 volt, go to step 8.
3. Turn ignition off. Allow 1/2 HO2S to cool down to room temperature. Disconnect 1/2 HO2S connector. On 2.5L and 4.0L Federal models, measure resistance between Orange/Dark Green and Brown/White wires at 1/2 HO2S connector (component side). On 4.0L Calif. models, measure resistance between Violet/Orange and Black wires at 1/2 HO2S connector (component side). On all models, if resistance is not 4-5 ohms, replace 1/2 HO2S. If resistance is 4-5 ohms, 1/2 HO2S heater element is okay. Go to next step (2.5L and 4.0L Federal models) or step 5 (4.0L Calif. models).
4. Ensure ignition is off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. 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 C16 at PCM C3 harness connector. (Scheme 28)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. Measure resistance between ground and Black 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 wire.
6. On all models, turn ignition on. Ensure 1/2 HO2S is still disconnected. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Orange/Dark Green wire (2.5L and 4.0L Federal models) or Violet/Orange wire (4.0L Calif. models) at 1/2 HO2S harness connector. If voltage is more than 11 volts, go to next step. If voltage is 11 volts or less, repair open in power circuit to 1/2 HO2S heater. See WIRING DIAGRAMS article.
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 1/2 HO2S voltage while wiggling connectors and wiring harness from 1/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0151 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0151 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 0.16 volt, turn ignition off and go to next step. If voltage is 0.16 volt or more, go to step 8 .
3. Disconnect 2/1 HO2S connector. Start engine and allow it to idle. Using scan tool, read 2/1 HO2S voltage. If voltage is 0.16 volt or less, go to next step. If voltage is more than 0.16 volt, replace 2/1 HO2S.
4. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. 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 2/1 HO2S and PCM.
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 2/1 HO2S voltage while wiggling connectors and wiring harness from 2/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0152 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0152 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, turn ignition off and go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Disconnect 2/1 HO2S connector. 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. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. 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 2/1 HO2S and PCM.
5. Measure resistance between Light Green/Red and Orange/Dark Green 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 Orange/Dark Green wires are shorted together. Repair wiring as necessary.
6. Measure resistance of Light Green/Red wire between 2/1 HO2S harness connector and terminal A26 at PCM C1 harness connector. (Scheme 28) 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 A4 at PCM C1 harness connector. (Scheme 28) 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 2/1 HO2S voltage while wiggling connectors and wiring harness from 2/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

1. Turn ignition on. 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. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Turn engine off. Using a voltmeter, backprobe Light Green/Red wire between 2/1 HO2S harness connector and terminal A26 at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine and allow it to idle for 4-5 minutes. Note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/2 HO2S signal circuit (Light Green/Red wire) between 2/1 HO2S and PCM.
4. Using voltmeter, backprobe Black/Light Blue between 2/1 HO2S harness connector and terminal A4 at PCM C1 harness connector. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 2/1 HO2S ground circuit (Black/Light Blue wire) between 2/1 HO2S and PCM.
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 2/1 HO2S voltage while wiggling connectors and wiring harness from 2/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

1. Turn ignition on. Using scan tool, check for 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 and wait 8 minutes or more to allow HO2S to cool down. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for 2 minutes or more. If voltage stays at 0.4-0.6 volt, go to next step. If voltage does not stay at 0.4-0.6 volt, go to step 7.
3. Turn ignition off. Allow 2/1 HO2S to cool down to room temperature. Disconnect 2/1 HO2S connector. Measure resistance between Orange/Dark Green and Brown/White wires at 2/1 HO2S connector (component side). If resistance is not 4-5 ohms, replace 2/1 HO2S. If resistance is 4-5 ohms, 2/1 HO2S heater element is okay. Go to next step.
4. Ensure ignition is off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. 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 C16 at PCM C3 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/White wire.
5. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Ensure 2/1 HO2S is still disconnected. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Orange/Dark Green 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 to 2/1 HO2S heater. See WIRING DIAGRAMS article.
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 2/1 HO2S voltage while wiggling connectors and wiring harness from 2/1 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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.

Note. 2/2 HO2S is located on rear exhaust pipe below front mini-catalytic converter. 2/2 HO2S may also be referred to as a downstream oxygen sensor.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0157 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0157 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 0.16 volt, turn ignition off and go to next step. If voltage is 0.16 volt or more, go to step 8 .
3. Disconnect 2/2 HO2S connector. Start engine and allow it to idle. Using scan tool, read 2/2 HO2S voltage. If voltage is 0.16 volt or less, go to next step. If voltage is more than 0.16 volt, replace 2/2 HO2S.
4. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Measure resistance between ground and 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 Tan wire between 2/2 HO2S and PCM.
5. Measure resistance between 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, Tan and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. Measure resistance between Tan and Black 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, Tan and Black 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 2/2 HO2S voltage while wiggling connectors and wiring harness from 2/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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 2/2 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.

Note. 2/2 HO2S is located on rear exhaust pipe below front mini-catalytic converter. 2/2 HO2S may also be referred to as a downstream oxygen sensor.

1. Turn ignition on. Using scan tool, check for DTCs. If GOOD TRIP counter is displayed for DTC P0158 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0158 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, turn ignition off go to next step. If voltage is 1.2 volts or less, go to step 9.
3. Disconnect 2/2 HO2S connector. 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. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Turn ignition on. Measure voltage between ground and 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 Tan wire between 2/2 HO2S and PCM.
5. Measure resistance between Tan and Violet/Orange 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, Tan and Violet/Orange wires are shorted together. Repair wiring as necessary.
6. Measure resistance of Tan wire between 2/2 HO2S harness connector and terminal A29 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Tan wire.
7. Measure resistance of Black/Light Blue wire between 2/2 HO2S harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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 2/2 HO2S voltage while wiggling connectors and wiring harness from 2/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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 2/2 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.

Note. 2/2 HO2S is located on rear exhaust pipe below front mini-catalytic converter. 2/2 HO2S may also be referred to as a downstream oxygen sensor.

1. Turn ignition on. 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. Repair exhaust system leaks as necessary. If exhaust system is okay, go to next step.
3. Turn engine off. Using a voltmeter, backprobe Tan wire between 2/2 HO2S harness connector and terminal A29 at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine and allow it to idle for 4-5 minutes. Note voltage reading. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 2/2 HO2S signal circuit (Tan wire) between 2/2 HO2S and PCM.
4. Using voltmeter, backprobe Black/Light Blue between 2/2 HO2S harness connector and terminal A4 at PCM C1 harness connector. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 2/2 HO2S ground circuit (Black/Light Blue wire) between 2/2 HO2S and PCM.
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 2/2 HO2S voltage while wiggling connectors and wiring harness from 2/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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 2/2 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.

Note. 2/2 HO2S is located on rear exhaust pipe below front mini-catalytic converter. 2/2 HO2S may also be referred to as a downstream oxygen sensor.

1. Turn ignition on. Using scan tool, check for 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 and wait 8 minutes or more to allow HO2S to cool down. Turn ignition on. Using scan tool, actuate HO2S HEATER TEST and monitor 2/2 HO2S voltage for 2 minutes or more. If voltage stays at 0.4-0.6 volt, go to next step. If voltage does not stay at 0.4-0.6 volt, go to step 7 .
3. Turn ignition off. Allow 2/2 HO2S to cool down to room temperature. Disconnect 2/2 HO2S connector. Measure resistance between Violet/Orange and Black wires at 2/2 HO2S connector (component side). If resistance is not 4-5 ohms, replace 2/2 HO2S. If resistance is 4-5 ohms, 2/2 HO2S heater element is okay. Go to next step.
4. Measure resistance between ground and Black 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 wire.
5. Turn ignition on. Ensure 2/2 HO2S is still disconnected. Using scan tool, actuate HO2S HEATER TEST. Measure voltage between ground and Violet/Orange 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 power circuit to 2/2 HO2S heater. See WIRING DIAGRAMS article.
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 2/2 HO2S voltage while wiggling connectors and wiring harness from 2/2 HO2S to Powertrain Control Module (PCM). PCM is located on firewall in right rear corner of engine compartment. 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 2/2 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.

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

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-12240-S25258205502000121500000) . 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 (3.23-3.96 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is more than specified, replace fuel filter/pressure regulator. Fuel filter/fuel pressure regulator is located in top of fuel tank. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article. If fuel pressure is as specified, go to step 6 .
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 (3.23-3.96 kg/cm 2 ). If fuel pressure is within specification, stop ASD fuel system activation, release fuel pressure and replace fuel supply line. If fuel pressure is not within specification, stop ASD fuel system activation and go to next step.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer in not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump module.
6. Turn ignition on. Using scan tool, read 1/1 HO2S voltage. If voltage is 0.4-0.6 volt, go to next step. If voltage is not 0.4-0.6 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 0.4-0.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for 3 minutes. If voltage does not stay at 0.4-0.6 volt, go to next step. If voltage stays at 0.4-0.6 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 0.92 volt, go to next step. If voltage is 0.92 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 above idle. 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 Closed Crankcase Ventilation (CCV) 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 any mechanical problems as necessary. If no mechanical problems exist, test is complete.
13. Turn ignition on. Disconnect 1/1 HO2S connector. Using scan tool, read 1/1 HO2S voltage. If voltage is not 0.4-0.6 volt, go to next step. If voltage is 0.4-0.6 volt, replace 1/1 HO2S.
14. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Measure resistance between ground and Black/Dark Green wire 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 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.

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0172 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0172 or displayed count is not "0", go to step 18.
2. Turn ignition off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-12240-S25258205502000121500000). 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 (3.23-3.96 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is more than specified, replace fuel filter/pressure regulator. Fuel filter/fuel pressure regulator is located in top of fuel tank. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article. If fuel pressure is as specified, go to step 6.
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 (3.23-3.96 kg/cm 2 ). If fuel pressure is within specification, stop ASD fuel system activation, release fuel pressure and replace fuel supply line. If fuel pressure is not within specification, stop ASD fuel system activation and go to next step.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer in not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump module.
6. Turn ignition on. Using scan tool, read 1/1 HO2S voltage. If voltage is 0.4-0.6 volt, go to next step. If voltage is not 0.4-0.6 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 0.4-0.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 1/1 HO2S voltage for 3 minutes. If voltage does not stay at 0.4-0.6 volt, go to next step. If voltage stays at 0.4-0.6 volt, replace 1/1 HO2S.
8. Start engine and allow it to idle. Ensure engine is at normal operating temperature and in closed loop mode. Using scan tool, select SYSTEM TESTS, then PURGE VAPORS TEST. Monitor short term adaptive value on scan tool and press "3" to flow. Short term adaptive value should change. If value changes, go to next step. If value does not change, go to CHECKING EVAPORATIVE EMISSION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in 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 0.92 volt, go to next step. If voltage is 0.92 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 above idle. 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 Closed Crankcase Ventilation (CCV) 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 any mechanical problems as necessary. If no mechanical problems exist, test is complete.
14. Turn ignition on. Disconnect 1/1 HO2S connector. Using scan tool, read 1/1 HO2S voltage. If voltage is not 0.4-0.6 volt, go to next step. If voltage is 0.4-0.6 volt, replace 1/1 HO2S.
15. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Black/Dark Green wire between 1/1 HO2S harness connector and terminal A24 at PCM C1 harness connector. (Scheme 28) 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 between PCM and 1/1 HO2S.
16. Ensure ignition is off. Reconnect PCM connectors. Start engine and allow it to idle. Measure voltage between ground and Black/Dark Green wire at 1/1 HO2S harness connector. If voltage is 0.6 volt or less, go to next step. If voltage is more than 0.6 volt, repair short to voltage in Black/Dark Green wire between 1/1 HO2S and PCM.
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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0174 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0174 or displayed count is not "0", go to step 16 .
2. Turn ignition off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-12240-S25258205502000121500000) . 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 (3.23-3.96 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is more than specified, replace fuel filter/pressure regulator. Fuel filter/fuel pressure regulator is located in top of fuel tank. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article. If fuel pressure is as specified, go to step 6 .
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 (3.23-3.96 kg/cm 2 ). If fuel pressure is within specification, stop ASD fuel system activation, release fuel pressure and replace fuel supply line. If fuel pressure is not within specification, stop ASD fuel system activation and go to next step.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer in not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump module.
6. Turn ignition on. Using scan tool, read 2/1 HO2S voltage. If voltage is 0.4-0.6 volt, go to next step. If voltage is not 0.4-0.6 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 0.4-0.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for 3 minutes. If voltage does not stay at 0.4-0.6 volt, go to next step. If voltage stays at 0.4-0.6 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 0.92 volt, go to next step. If voltage is 0.92 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 above idle. 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, go to next step. If ECT sensor value increase is erratic, 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 Closed Crankcase Ventilation (CCV) 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 any mechanical problems as necessary. If no mechanical problems exist, test is complete.
13. Turn ignition on. Disconnect 2/1 HO2S connector. Using scan tool, read 2/1 HO2S voltage. If voltage is not 0.4-0.6 volt, go to next step. If voltage is 0.4-0.6 volt, replace 2/1 HO2S.
14. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. 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.
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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0175 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0175 or displayed count is not "0", go to step 18.
2. Turn ignition off. Release fuel pressure. See «FUEL SYSTEM PRESSURE RELEASE»(ref-12240-S25258205502000121500000). 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 (3.23-3.96 kg/cm 2 ). If fuel pressure is less than specified, go to next step. If fuel pressure is more than specified, replace fuel filter/pressure regulator. Fuel filter/fuel pressure regulator is located in top of fuel tank. See FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article. If fuel pressure is as specified, go to step 6.
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 (3.23-3.96 kg/cm 2 ). If fuel pressure is within specification, stop ASD fuel system activation, release fuel pressure and replace fuel supply line. If fuel pressure is not within specification, stop ASD fuel system activation and go to next step.
4. Release fuel pressure. Remove fuel pump module and inspect fuel inlet strainer. If fuel inlet strainer is plugged, replace fuel pump inlet strainer. If fuel inlet strainer in not plugged, go to next step.
5. At this time, fuel pump module is assumed to be defective. Replace fuel pump module.
6. Turn ignition on. Using scan tool, read 2/1 HO2S voltage. If voltage is 0.4-0.6 volt, go to next step. If voltage is not 0.4-0.6 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 0.4-0.6 volt. Using scan tool, actuate HO2S HEATER TEST and monitor 2/1 HO2S voltage for 3 minutes. If voltage does not stay at 0.4-0.6 volt, go to next step. If voltage stays at 0.4-0.6 volt, replace 2/1 HO2S.
8. Start engine and allow it to idle. Ensure engine is at normal operating temperature and in closed loop mode. Using scan tool, select SYSTEM TESTS, then PURGE VAPORS TEST. Monitor short term adaptive value on scan tool and press "3" to flow. Short term adaptive value should change. If value changes, go to next step. If value does not change, go to CHECKING EVAPORATIVE EMISSION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in 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 0.92 volt, go to next step. If voltage is 0.92 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 above idle. 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 Closed Crankcase Ventilation (CCV) 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 any mechanical problems as necessary. If no mechanical problems exist, test is complete.
14. Turn ignition on. Disconnect 2/1 HO2S connector. Using scan tool, read 2/1 HO2S voltage. If voltage is not 0.4-0.6 volt, go to next step. If voltage is 0.4-0.6 volt, replace 2/1 HO2S.
15. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Light Green/Red wire between 2/1 HO2S harness connector and terminal A26 at PCM C1 harness connector. (Scheme 28) 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. Reconnect PCM connectors. Start engine and allow it to idle. Measure voltage between ground and Light Green/Red wire at 2/1 HO2S harness connector. If voltage is 0.6 volt or less, go to next step. If voltage is more than 0.6 volt, repair short to voltage in Light Green/Red wire between 2/1 HO2S and PCM.
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, check for 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. Turn ignition on. Using a test light connected to ground, backprobe Dark Green/Light Green wire at fuel injector No. 1 harness connector. Using scan tool, actuate fuel injector No. 1. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair power circuit to fuel injector No. 1. See WIRING DIAGRAMS article.
3. Using a test light connected to positive battery voltage, backprobe White/Dark Blue wire at fuel injector No. 1 harness connector. Using scan tool, actuate fuel injector No. 1 while observing test light. 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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of White/Dark Blue wire between fuel injector No. 1 harness connector and terminal B4 at PCM C2 harness connector. (Scheme 28) 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. Using ohmmeter, measure resistance between ground and White/Dark Blue wire at fuel injector No. 1 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 Blue wire between PCM and fuel injector No. 1.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. Start engine and allow it to idle. Wiggle wiring harness from fuel injector No. 1 to PCM. PCM is located on firewall in right rear corner of engine compartment. If engine misses or stalls while wiggling wiring harness, repair wiring harness as necessary where wiggling caused engine to misfire or stall. If engine does not misfire or stall while wiggling wiring harness, go to next step.
8. 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, go to next step.
9. Ensure ignition is on, with engine off. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0201: INJECTOR #1 CONTROL CIRCUIT returns, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If DTC P0201: INJECTOR #1 CONTROL CIRCUIT does not return, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, check for 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. Turn ignition on. Using a test light connected to ground, backprobe Dark Green/Light Green wire at fuel injector No. 2 harness connector. Using scan tool, actuate fuel injector No. 2. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair power circuit to fuel injector No. 2. See WIRING DIAGRAMS article.
3. Using a test light connected to positive battery voltage, backprobe Tan wire at fuel injector No. 2 harness connector. Using scan tool, actuate fuel injector No. 2 while observing test light. If test light does not blink/flicker, go to next step. If test light blinks/flickers, replace fuel injector.
4. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Tan wire between fuel injector No. 2 harness connector and terminal B15 at PCM C2 connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Tan wire.
5. Using ohmmeter, measure resistance between ground and Tan wire at fuel injector No. 2 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 Tan wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. Start engine and allow it to idle. Wiggle wiring harness from fuel injector No. 2 to PCM. PCM is located on firewall in right rear corner of engine compartment. If engine misses or stalls while wiggling wiring harness, repair wiring harness as necessary where wiggling caused engine to misfire or stall. If engine does not misfire or stall while wiggling wiring harness, go to next step.
8. 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, go to next step.
9. Ensure ignition is on, with engine off. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0202: INJECTOR #2 CONTROL CIRCUIT returns, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If DTC P0202: INJECTOR #2 CONTROL CIRCUIT does not return, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, check for 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. Turn ignition on. Using a test light connected to ground, backprobe Dark Green/Light Green wire at fuel injector No. 3 harness connector. Using scan tool, actuate fuel injector No. 3. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair power circuit to fuel injector No. 3. See WIRING DIAGRAMS article.
3. Using a test light connected to positive battery voltage, backprobe Yellow/White wire at fuel injector No. 3 harness connector. Using scan tool, actuate fuel injector No. 3 while observing test light. 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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Yellow/White wire between fuel injector No. 3 harness connector and terminal B5 at PCM C2 connector. (Scheme 28) 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. Using ohmmeter, measure resistance between ground and Yellow/White wire at fuel injector No. 3 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/White wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. Start engine and allow it to idle. Wiggle wiring harness from fuel injector No. 3 to PCM. PCM is located on firewall in right rear corner of engine compartment. If engine misses or stalls while wiggling wiring harness, repair wiring harness as necessary where wiggling caused engine to misfire or stall. If engine does not misfire or stall while wiggling wiring harness, go to next step.
8. 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, go to next step.
9. Ensure ignition is on, with engine off. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0203: INJECTOR #3 CONTROL CIRCUIT returns, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If DTC P0203: INJECTOR #3 CONTROL CIRCUIT does not return, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, check for 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. Turn ignition on. Using a test light connected to ground, backprobe Dark Green/Light Green wire at fuel injector No. 4 harness connector. Using scan tool, actuate fuel injector No. 4. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair power circuit to fuel injector No. 4. See WIRING DIAGRAMS article.
3. Using a test light connected to positive battery voltage, backprobe Light Blue/Brown wire at fuel injector No. 4 harness connector. Using scan tool, actuate fuel injector No. 4 while observing test light. 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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Light Blue/Brown wire between fuel injector No. 4 harness connector and terminal B16 at PCM C2 connector. (Scheme 28) 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. Using ohmmeter, measure resistance between ground and Light Blue/Brown wire at fuel injector No. 4 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 Blue/Brown wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. Start engine and allow it to idle. Wiggle wiring harness from fuel injector No. 4 to PCM. PCM is located on firewall in right rear corner of engine compartment. If engine misses or stalls while wiggling wiring harness, repair wiring harness as necessary where wiggling caused engine to misfire or stall. If engine does not misfire or stall while wiggling wiring harness, go to next step.
8. 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, go to next step.
9. Ensure ignition is on, with engine off. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0204: INJECTOR #4 CONTROL CIRCUIT returns, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If DTC P0204: INJECTOR #4 CONTROL CIRCUIT does not return, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, check for 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. Turn ignition on. Using a test light connected to ground, backprobe Dark Green/Light Green wire at fuel injector No. 5 harness connector. Using scan tool, actuate fuel injector No. 5. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair power circuit to fuel injector No. 5. See WIRING DIAGRAMS article.
3. Using a test light connected to positive battery voltage, backprobe Pink/Black wire (with Calif. emissions) or Gray wire (with Federal emissions) at fuel injector No. 5 harness connector. Using scan tool, actuate fuel injector No. 5 while observing test light. 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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Pink/Black wire (with Calif. emissions) or Gray wire (with Federal emissions) Pink/Black wire between fuel injector No. 5 harness connector and terminal B6 at PCM C2 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Pink/Black wire or Gray wire.
5. Using ohmmeter, measure resistance between ground and Pink/Black wire (with Calif. emissions) or Gray wire (with Federal emissions) at fuel injector No. 5 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/Black wire or Gray wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. Start engine and allow it to idle. Wiggle wiring harness from fuel injector No. 5 to PCM. PCM is located on firewall in right rear corner of engine compartment. If engine misses or stalls while wiggling wiring harness, repair wiring harness as necessary where wiggling caused engine to misfire or stall. If engine does not misfire or stall while wiggling wiring harness, go to next step.
8. 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, go to next step.
9. Ensure ignition is on, with engine off. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0205: INJECTOR #5 CONTROL CIRCUIT returns, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If DTC P0205: INJECTOR #5 CONTROL CIRCUIT does not return, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, check for 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. Turn ignition on. Using a test light connected to ground, backprobe Dark Green/Light Green wire at fuel injector No. 6 harness connector. Using scan tool, actuate fuel injector No. 6. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair power circuit to fuel injector No. 6. See WIRING DIAGRAMS article.
3. Using a test light connected to positive battery voltage, backprobe Light Green/Black wire at fuel injector No. 6 harness connector. Using scan tool, actuate fuel injector No. 6 while observing test light. 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 on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Light Green/Black wire between fuel injector No. 6 harness connector and terminal B12 at PCM C2 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Light Green/Black wire.
5. Using ohmmeter, measure resistance between ground and Light Green/Black wire at fuel injector No. 6 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/Black wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. Start engine and allow it to idle. Wiggle wiring harness from fuel injector No. 6 to PCM. PCM is located on firewall in right rear corner of engine compartment. If engine misses or stalls while wiggling wiring harness, repair wiring harness as necessary where wiggling caused engine to misfire or stall. If engine does not misfire or stall while wiggling wiring harness, go to next step.
8. 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, go to next step.
9. Ensure ignition is on, with engine off. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0206: INJECTOR #6 CONTROL CIRCUIT returns, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If DTC P0206: INJECTOR #6 CONTROL CIRCUIT does not return, no problem is indicated at this time. 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, no problem is indicated. Test is complete.
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 next step. If adaptive fuel percentages are more than plus or minus 15 percent, check fuel delivery. See FUEL SYSTEMS under 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 DTC returns, go to next step. If 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 more than plus or minus 15 percent, check fuel delivery. See FUEL SYSTEMS under SYSTEM & COMPONENT TESTING article. If adaptive fuel percentages are not more than plus or minus 15 percent, go to next step.
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 Closed Crankcase Ventilation (CCV) 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. Ignition Coil Circuit Spark Plugs 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 DTC 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. Backprobe lab scope lead to terminal A8 (Gray/Black wire) at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. 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 A18 (Tan/Yellow wire) at PCM C1 harness connector. (Scheme 28) 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 A8 (Gray/Black wire) at PCM C1 harness connector. (Scheme 28) Observe lab scope screen and start engine. Wiggle wiring harness from CKP sensor to PCM while observing lab scope pattern. CKP sensor is mounted to left side of transmission bellhousing. 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 connector. CKP sensor is mounted to left side of transmission bellhousing. CKP sensor connector is located on top of intake manifold, near firewall. Turn ignition on. Measure voltage between ground and Orange 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 15.
7. Measure voltage between ground and 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. Measure resistance between ground and Black/Light Blue wire at CKP sensor 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.
9. Turn ignition off. Remove CKP sensor. Inspect notches on flywheel/drive plate for damage or debris. On 2.5L, flywheel/drive plate contains 2 sets of notches which contain 4 slots each on outer edge of flywheel/drive plate. On 4.0L, flywheel/drive plate contains 3 sets notches which contain 4 slots in each set. On all models, check slotted areas for damage or any foreign debris. If slotted areas on flywheel/drive plate are okay and no debris exists, replace CKP sensor. If slotted areas on flywheel/drive plate are damaged or debris exists, repair or replace flywheel/drive plate as necessary.
10. Turn ignition off. Ensure CKP sensor connector is still disconnected. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Gray/Black wire at CKP 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/Black wire between CKP sensor and PCM.
11. Measure resistance of Gray/Black wire between CKP harness connector and terminal A8 at PCM C1 harness connector. (Scheme 28) 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 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 Orange and Gray/Black wires at CKP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange and Gray/Black 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. Measure resistance between ground and Orange wire at CKP 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 PCM and CKP sensor.
16. Measure resistance of Orange wire between CKP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
17. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and Orange 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 Orange wire between CKP sensor and PCM.
18. At this time, PCM is assumed to be defective. Replace PCM.

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 A8 (Gray/Black wire) at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. 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 A18 (Tan/Yellow wire) at PCM C1 harness connector. (Scheme 28) 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 A18 (Tan/Yellow wire) at PCM C1 harness connector. (Scheme 28) Observe lab scope screen and start engine. Wiggle wiring harness from CMP sensor to PCM while observing lab scope pattern. On 2.5L, CMP sensor is located in distributor. On 4.0L, CMP sensor is mounted on top of oil pump drive shaft assembly and is located on right side of engine, near oil filter. 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 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 2.5L, CMP sensor is located in distributor. On 4.0L, CMP sensor is mounted on top of oil pump drive shaft assembly and is located on right side of engine, near oil filter. On all models, turn ignition on. Measure voltage between ground and Orange 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 15.
7. Measure voltage between ground and Tan/Yellow 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 on firewall in right rear corner of engine compartment. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Black/Light Blue wire between CMP sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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. On 2.5L, remove distributor cap and rotor. Inspect pulse ring for damage or misalignment, and verify pulse ring rotates when engine is cranked. If pulse ring is damaged, repair or replace distributor and/or pulse ring as necessary. If pulse ring is okay, replace CMP sensor. On 4.0L, remove CMP sensor and oil pump drive shaft. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. Inspect oil pump drive shaft. Replace oil pump drive shaft as necessary. If oil pump drive shaft is okay, replace CMP sensor.
10. Turn ignition off. Ensure CMP sensor connector is still disconnected. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Tan/Yellow wire at CMP 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 Tan/Yellow wire between CMP sensor and PCM.
11. Measure resistance of Tan/Yellow wire between CMP harness connector and terminal A18 at PCM C1 harness connector. (Scheme 28) 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 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 Orange and Tan/Yellow wires at CMP sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Orange and Tan/Yellow 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. Measure resistance between ground and Orange wire at CMP 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 PCM and CMP sensor.
16. Measure resistance of Orange wire between CMP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
17. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and Orange 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 Orange wire between CMP sensor and PCM.
18. 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 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. Coil is mounted on engine, rear of distributor. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Measure resistance between Dark Green/Orange and Gray wires at ignition coil connector (component side). If resistance is 0.6-0.9 ohm, go to next step. If resistance is not 0.6-0.9 ohm, replace ignition coil. NOTE: In the following step, when checking for power at the coil connector, Auto Shutdown (ASD) relay must be activated. When PCM receives a command to activate the ASD relay, the PCM toggles the ASD relay control circuit (2 seconds on and 2 seconds off) and voltage is supplied via the ASD relay to the coils. ASD relay can be activated by using a scan tool and activating generator field or ASD relay.
3. Turn ignition on. Using a test light connected to ground, probe Dark Green/Light Green wire at ignition coil harness connector. Using scan tool, actuate generator field or ASD relay and observe test light. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in ASD relay output circuit to ignition coil. See WIRING DIAGRAMS article.
4. Turn ignition off. Ensure ignition coil rail connector is still disconnected. Using a test light connected to positive battery voltage, probe Gray wire at ignition coil harness connector while cranking engine. If test light does not blink/flicker, go to next step. If test light blinks/flickers, no problem is indicated at this time. Test is complete.
5. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Gray wire between ignition coil harness connector and terminal A7 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Gray wire.
6. Measure resistance between ground and 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 Gray 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. 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. Start engine and allow it to idle. With engine running, wiggle wiring harness from ignition coil rail to PCM. PCM is located on firewall in right rear corner of engine compartment. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and displayed count changes to "0", or engine misses, repair wiring where wiggling caused engine to miss. If engine does not miss 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.

Note. A one-piece coil rail assembly containing 3 individual coils is used. Coil rail assembly is located on top of engine, right of valve cover. Individual coils cannot be replaced separately. If any coils are defective, coils and coil rail assembly must be replaced as an assembly.

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 rail connector. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Measure resistance between Dark Green/Light Green and Gray wires at ignition coil rail connector (component side). If resistance is 0.6-0.9 ohm, go to next step. If resistance is not 0.6-0.9 ohm, replace ignition coil rail. NOTE: In the following step, when checking for power at the coil connector, Auto Shutdown (ASD) relay must be activated. When PCM receives a command to activate the ASD relay, the PCM toggles the ASD relay control circuit (2 seconds on and 2 seconds off) and voltage is supplied via the ASD relay to the coils. ASD relay can be activated by using a scan tool and activating generator field or ASD relay.
3. Turn ignition on. Using a test light connected to ground, probe Dark Green/Light Green wire at ignition coil rail harness connector. Using scan tool, actuate generator field or ASD relay and observe test light. If test light illuminates brightly, go to next step. If test light does not illuminate brightly, repair open or high resistance in ASD relay output circuit to ignition coil rail. See WIRING DIAGRAMS article.
4. Turn ignition off. Ensure ignition coil rail connector is still disconnected. Using a test light connected to positive battery voltage, probe Gray wire at ignition coil rail harness connector while cranking engine. If test light does not blink/flicker, go to next step. If test light blinks/flickers, no problem is indicated at this time. Test is complete.
5. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Gray wire between ignition coil rail harness connector and terminal A7 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Gray wire.
6. Measure resistance between ground and Gray wire at ignition coil rail 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 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. 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. Start engine and allow it to idle. With engine running, wiggle wiring harness from ignition coil rail to PCM. PCM is located on firewall in right rear corner of engine compartment. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and displayed count changes to "0", or engine misses, repair wiring where wiggling caused engine to miss. If engine does not miss 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.

Note. A one-piece coil rail assembly containing 3 individual coils is used. Coil rail assembly is located on top of engine, right of valve cover. Individual coils cannot be replaced separately. If any coils are defective, coils and coil rail assembly must be replaced as an assembly.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0352 and displayed count is "0", go to next step. If DTC GOOD TRIP counter is not displayed for DTC P0352 or displayed count is not "0", go to step 8.
2. Turn ignition off. Disconnect ignition coil rail connector. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Measure resistance between Dark Green/Light Green and Dark Blue/Tan wires at ignition coil rail connector (component side). If resistance is 0.6-0.9 ohm, go to next step. If resistance is not 0.6-0.9 ohm, replace ignition coil rail. NOTE: In the following step, when checking for power at the coil connector, Auto Shutdown (ASD) relay must be activated. When PCM receives a command to activate the ASD relay, the PCM toggles the ASD relay control circuit (2 seconds on and 2 seconds off) and voltage is supplied via the ASD relay to the coils. ASD relay can be activated by using a scan tool and activating generator field or ASD relay.
3. Turn ignition on. Using a test light connected to ground, probe Dark Green/Light Green wire at ignition coil rail harness connector. Using scan tool, actuate generator field or ASD relay and observe test light. If test light does not illuminate brightly, repair open or high resistance in ASD relay output circuit to ignition coil rail. See WIRING DIAGRAMS article.
4. Turn ignition off. Ensure ignition coil rail connector is still disconnected. Using a test light connected to positive battery voltage, probe Dark Blue/Tan wire at ignition coil rail harness connector while cranking engine. If test light does not blink or flicker, go to next step. If test light blinks or flickers, no problem is indicated at this time. Test is complete.
5. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Dark Blue/Tan wire between ignition coil rail harness connector and terminal B9 at PCM C2 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Dark Blue/Tan wire.
6. Measure resistance between ground and Dark Blue/Tan wire at ignition coil rail 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/Tan 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. 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. Start engine and allow it to idle. With engine running, wiggle wiring harness from ignition coil rail to PCM. PCM is located on firewall in right rear corner of engine compartment. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and displayed count changes to "0", or engine misses, repair wiring where wiggling caused engine to miss. If engine does not miss 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.

Note. A one-piece coil rail assembly containing 3 individual coils is used. Coil rail assembly is located on top of engine, right of valve cover. Individual coils cannot be replaced separately. If any coils are defective, coils and coil rail assembly must be replaced as an assembly.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0353 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P0353 or displayed count is not "0", go to step 8.
2. Turn ignition off. Disconnect ignition coil rail connector. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Measure resistance between Dark Green/Light Green and Red/Yellow wires at ignition coil rail connector (component side). If resistance is 0.6-0.9 ohm, go to next step. If resistance is not 0.6-0.9 ohm, replace ignition coil rail. NOTE: In the following step, when checking for power at the coil connector, Auto Shutdown (ASD) relay must be activated. When PCM receives a command to activate the ASD relay, the PCM toggles the ASD relay control circuit (2 seconds on and 2 seconds off) and voltage is supplied via the ASD relay to the coils. ASD relay can be activated by using a scan tool and activating generator field or ASD relay.
3. Turn ignition on. Using a test light connected to ground, probe Dark Green/Light Green wire at ignition coil rail harness connector. Using scan tool, actuate generator field or ASD relay and observe test light. If test light does not illuminate brightly, repair open or high resistance in ASD relay output circuit to ignition coil rail. See WIRING DIAGRAMS article.
4. Turn ignition off. Ensure ignition coil rail connector is still disconnected. Using a test light connected to positive battery voltage, probe Red/Yellow wire at ignition coil rail harness connector while cranking engine. If test light does not blink/flicker, go to next step. If test light blinks/flickers, no problem is indicated at this time. Test is complete.
5. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Red/Yellow wire between ignition coil rail harness connector and terminal A1 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open or high resistance in Red/Yellow wire.
6. Measure resistance between ground and Red/Yellow wire at ignition coil rail 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/Yellow 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. 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. Start engine and allow it to idle. With engine running, wiggle wiring harness from ignition coil rail to PCM. PCM is located on firewall in right rear corner of engine compartment. Using scan tool, read DTCs. If GOOD TRIP counter is displayed and displayed count changes to "0", or engine misses, repair wiring where wiggling caused engine to miss. If engine does not miss 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.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0420 and displayed count is "0", go to step 3 . If GOOD TRIP counter is not displayed for DTC P0420 or displayed count is not "0", go to next step.
2. At this time, conditions for catalyst efficiency failure do not exist or is an intermittent problem. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0420: 1/1 CATALYTIC CONVERTER EFFICIENCY returns, go to next step. If DTC P0420: 1/1 CATALYTIC CONVERTER EFFICIENCY does not return, no problem is indicated at this time. Test is complete.
3. Start engine and allow it to idle. Check for exhaust leaks between engine and downstream HO2S. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
4. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace catalytic converter. If engine mechanical condition is okay, go to next step.
5. If downstream HO2S has been replaced without replacing upstream HO2S, replace upstream HO2S. If downstream HO2S has not been replaced recently or downstream HO2S has been replaced along with upstream HO2S, replace catalytic converter.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter is displayed for DTC P0432 and displayed count is "0", go to step 3 . If GOOD TRIP counter is not displayed for DTC P0432 or displayed count is not "0", go to next step.
2. At this time, conditions for catalyst efficiency failure do not exist or is an intermittent problem. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P0432: 2/1 CATALYTIC CONVERTER EFFICIENCY returns, go to next step. If DTC P0432: 2/1 CATALYTIC CONVERTER EFFICIENCY does not return, no problem is indicated at this time. Test is complete.
3. Start engine and allow it to idle. Check for exhaust leaks between engine and downstream HO2S. Repair exhaust system as necessary. If exhaust system is okay, go to next step.
4. Check exhaust system for excessive smoke caused by internal oil or coolant consumption. Repair engine mechanical condition as necessary and replace catalytic converter. If engine mechanical condition is okay, go to next step.
5. If downstream HO2S has been replaced without replacing upstream HO2S, replace upstream HO2S. If downstream HO2S has not been replaced recently or downstream HO2S has been replaced along with upstream HO2S, replace catalytic converter.

Note. EVAP purge solenoid may also be referred to as EVAP canister purge solenoid or duty cycle EVAP purge solenoid.

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. Locate EVAP canister on left side of engine compartment. Visually inspect EVAP canister for damage or signs that fuel has entered canister. Any sign of fuel in EVAP canister may indicate a defective rollover valve. Rollover valve is located on top of fuel tank and is not serviceable. If rollover valve is defective, fuel tank must be replaced. Replace EVAP canister and/or fuel tank as necessary. If EVAP canister is okay, go to next step.
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 is located on a bracket mounted at left side of engine compartment. (Scheme 33) 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 33

1. Turn ignition on. Using scan tool, check for DTCs. If DTC GOOD TRIP counter is not displayed and equal to zero, go to step 4. If DTC GOOD TRIP counter is displayed and equal to zero, 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 on a bracket mounted at left side of engine compartment. (Scheme 33) 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 and set VENT valve to CLOSED. 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. Turn timer off. 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 DRBIII(R) has timed out, restart EVAP system pressure pump self-test. Set EVAP system testing kit PRESSURE/HOLD valve to OPEN. Set VENT valve to CLOSED. 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 valve, EVAP canister, LDP and EVAP purge solenoid. Rollover valve is located on top of fuel tank next to fuel pump module. Rollover valve is not serviceable. If rollover valve is defective, fuel tank must be replaced. EVAP canister is located on left side of engine compartment. 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. Go to step 2. If monitor passes, no problem is indicated at this time. Test is complete.

Note. EVAP purge solenoid may also be referred to as EVAP canister purge solenoid or duty cycle EVAP purge solenoid.

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. Ensure ignition is off. Disconnect EVAP purge solenoid connector. EVAP purge solenoid is located on a bracket mounted at left side of engine compartment. (Scheme 33) 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. Using a voltmeter, measure voltage between ground and Red/Light Green wire at EVAP purge solenoid harness connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, check for open in Red/Light Green wire (fused ignition switch output circuit) between EVAP purge solenoid and fuse block. Fuse block is located behind glove box. Also check fuse No. 11 (10-amp) in fuse block.
4. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Pink/Black wire between EVAP purge solenoid harness connector and terminal C20 at PCM C3 harness connector. (Scheme 28) If resistance is 5 ohms or more, repair open in Pink/Black wire between EVAP purge solenoid and PCM. If resistance is less than 5 ohms, go to next step.
5. Measure resistance between ground and Pink/Black 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/Black 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 is located on a bracket mounted at left side of engine compartment. (Scheme 33) PCM is located on firewall in right rear corner of engine compartment. 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. Turn ignition off. Remove fuel tank. See FUEL TANK under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article. Remove fuel pump module from fuel tank. Visually inspect inside of fuel tank for obstructions or deformities. Repair or replace fuel tank as necessary. If fuel tank is okay, go to next step.
2. At this time, fuel level sensor is assumed to be defective. Replace fuel level sensor. Fuel level sensor is located on fuel pump module and can be replaced separately. See FUEL LEVEL SENSOR under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article.

1. Turn ignition on. Using scan tool, read FUEL LEVEL SENSOR voltage. If voltage is less than 0.4 volt, go to next step. If voltage is 0.4 volt or more, go to step 6.
2. Turn ignition off. Disconnect fuel pump module connector. Fuel pump module is mounted in top of fuel tank. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Using scan tool, read FUEL LEVEL SENSOR voltage. If voltage does not change from less than 0.4 volt to more than 9.0 volts, go to next step. If voltage changes from less than 0.4 volt to more than 9.0 volts, replace fuel level sensor. Fuel level sensor is located on fuel pump module and can be replaced separately. See FUEL LEVEL SENSOR under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article.
3. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between terminal A4 (Black/Light Blue wire) at PCM C1 connector and terminal C26 (Dark Blue/Light Green wire) at PCM C3 harness connector. (Scheme 28) If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Black/Light Blue and Dark Blue/Light Green wires are shorted together. Repair wiring as necessary.
4. Measure resistance between ground and terminal C26 (Dark Blue/Light Green 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/Light Green wire.
5. At this time, PCM is assumed to be defective. Replace PCM.
6. Ensure ignition is on, with engine off. Using scan tool, monitor FUEL LEVEL SENSOR voltage while wiggling fuel pump module connector and wiring harness. Fuel pump module is mounted in top of fuel tank. If voltage changes while wiggling wiring harness, repair wiring harness where wiggling caused voltage to change. If voltage does not change while wiggling wiring harness, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, read FUEL LEVEL SENSOR voltage. If voltage is more than 9.9 volts, go to next step. If voltage is 9.9 volts or less, go to step 6.
2. Turn ignition off. Disconnect fuel pump module connector. Fuel pump module is mounted in top of fuel tank. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, connect a jumper wire between Dark Blue/Light Green wire and Black/Light Blue wire at fuel pump module harness connector. Turn ignition on. Using scan tool, read FUEL LEVEL SENSOR voltage. If voltage did not change from more than 9.9 volts to less than 0.4 volt, go to next step. If voltage changed from more than 9.9 volts to less than 0.4 volt, replace fuel level sensor. Fuel level sensor is located on fuel pump module and can be replaced separately. See FUEL LEVEL SENSOR under FUEL SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION article.
3. Turn ignition off. Disconnect jumper wire. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Black/Light Blue wire between fuel pump module harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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.
4. Turn ignition off. Measure resistance of Dark Blue/Light Green wire between fuel pump module harness connector and terminal C 26 at PCM C3 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Blue/Light Green wire.
5. At this time, PCM is assumed to be defective. Replace PCM.
6. Ensure ignition is on, with engine off. Using scan tool, monitor FUEL LEVEL SENSOR voltage while wiggling fuel pump module connector and wiring harness. Fuel pump module is mounted in top of fuel tank. If voltage changes while wiggling wiring harness, repair wiring harness where wiggling caused voltage to change. If voltage does not change while wiggling wiring harness, visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, no problem is indicated at this time. Test is complete.

1. Turn ignition off. Raise and support vehicle so wheels are free to rotate. Start engine and allow it to idle. Using scan tool, read VSS signal. Place transmission in any forward gear and allow wheels to rotate. If scan tool displays more than zero MPH, go to next step. If scan tool displays zero MPH, go to step 3.
2. At this time, condition required to set DTC is not present. 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, no problem is indicated at this time. Test is complete.
3. Turn ignition off. Inspect VSS speedometer pinion gear adapter for proper seating and positioning. Adapter is located on transmission extension housing. Repair adapter as necessary. If adapter is okay, go to next step.
4. Disconnect VSS connector. VSS connector is attached to adapter, located on transmission extension housing. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on, with engine off. Using a voltmeter, measure voltage between ground and Violet/Orange wire at VSS harness connector. If voltage is more than 4 volts, go to next step. If voltage is 4 volts or less, repair open in Violet/Orange wire between VSS and PCM.
5. Connect one end of a jumper wire to White/Orange wire at VSS harness connector. Ensure ignition is on, with engine off. Using scan tool, monitor VSS signal when tapping other end of jumper wire to Black/Light Blue wire at VSS harness connector several times. If scan tool displays more than zero MPH, go to next step. If scan tool displays zero MPH, go to step 7.
6. Turn ignition off. Remove VSS and inspect speedometer pinion gear. Repair speedometer pinion gear as necessary. If speedometer pinion gear is okay, replace VSS.
7. Turn ignition off. Disconnect jumper wire. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Black/Light Blue wire between VSS harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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 VSS and PCM.
8. Measure resistance of White/Orange wire between VSS harness connector and terminal B27 at PCM C2 harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open White/Orange wire between VSS and PCM.
9. Measure resistance between ground and White/Orange wire at VSS 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/Orange wire.
10. Ensure VSS and PCM connectors are still disconnected. Measure resistance between ground and Black/Light Blue wire at VSS harness connector. If resistance is 5 ohms or more, replace PCM. If resistance is less than 5 ohms, repair short to ground in Black/Light Blue wire.

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 for DTC P0505 is not displayed or displayed count is not "0", go to step 22.
2. Start engine and allow it to idle. Disconnect IAC motor connector. Measure voltage between ground and Gray/Red wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step 19.
3. With engine still idling, measure voltage between ground and Yellow/Black wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step 16.
4. With engine still idling, measure voltage between ground and Brown/White wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step 13.
5. With engine still idling, measure voltage between ground and Violet/Black wire at IAC motor harness connector. If voltage changes to more than 5 volts at any time, go to next step. If voltage does not change to more than 5 volts at any time, go to step 10.
6. Turn engine off. Ensure IAC motor is still disconnected. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between Gray/Red wire and Yellow/Black, Brown/White and Violet/Black wires at IAC motor harness connector. 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. If all resistance readings are 5 ohms or more, go to next step.
7. Measure resistance between Yellow/Black wire and Brown/White and Violet/Black wires at IAC motor harness connector. 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. If all resistance readings are 5 ohms or more, go to next step.
8. Measure resistance between Brown/White and Violet/Black wires at IAC motor harness connector. If resistance is less than 5 ohms, Brown/White and Violet/Black wires are shorted together. Repair wiring as necessary. If all resistance is 5 ohms or more, go to next step.
9. At this time, IAC motor is assumed to be defective. Replace IAC motor.
10. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Violet/Black wire between IAC motor harness connector and terminal A20 at PCM C1 connector. (Scheme 28) If resistance is 5 ohms or more, repair open in Violet/Black wire. If resistance is less than 5 ohms, go to next step.
11. Measure resistance between ground and Violet/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 Violet/Black wire between IAC motor and PCM.
12. At this time, PCM is assumed to be defective. Replace PCM.
13. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between IAC motor harness connector and terminal A11 at PCM C1 connector. (Scheme 28) If resistance is 5 ohms or more, repair open in Brown/White wire. If resistance is less than 5 ohms, go to next step.
14. Measure resistance between ground and 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.
15. At this time, PCM is assumed to be defective. Replace PCM.
16. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Yellow/Black wire between IAC motor harness connector and terminal A10 at PCM C1 connector. (Scheme 28) If resistance is 5 ohms or more, repair open in Yellow/Black wire. If resistance is less than 5 ohms, go to next step.
17. Measure resistance between ground and 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.
18. At this time, PCM is assumed to be defective. Replace PCM.
19. Turn ignition off. Ensure IAC motor is disconnected. Disconnect PCM connectors. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Gray/Red wire between IAC motor harness connector and terminal A19 at PCM C1 connector. (Scheme 28) If resistance is 5 ohms or more, repair open in Gray/Red wire. If resistance is less than 5 ohms, go to next step.
20. Measure resistance between ground and 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.
21. At this time, PCM is assumed to be defective. Replace PCM.
22. Start engine and allow it to idle. Using scan tool, go to SYSTEM TESTS and select IAC WIGGLE TEST. While monitoring IAC motor operation, wiggle wiring harness from IAC motor to PCM. PCM is located on firewall in right rear corner of engine compartment. If IAC motor stops operating at any time while wiggling wiring harness, repair wiring harness where wiggling caused IAC motor to stop operating. If IAC motor does not stop operating at any time while wiggling wiring harness, go to next step.
23. Visually inspect related connectors and wiring harness for damage. Repair wiring as necessary. If wiring is okay, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, read oil pressure sensor voltage. If voltage is 0.1 volt or less, go to step 3 . If voltage is more than 0.1 volt, go to next step.
2. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Check for any related technical service bulletins that may apply. Start engine. Using scan tool, monitor oil pressure sensor voltage while wiggling oil pressure sensor wiring harness and connector. Oil pressure sensor is located on right side of engine near distributor (2.5L) or camshaft position sensor (4.0L) and has a Black 3-pin connector. If oil pressure sensor voltage changes while wiggling wiring harness, repair wiring harness or connector where wiggling caused voltage to change. If voltage does not change, no problem is indicated at this time. Test is complete.
3. Turn ignition off. Disconnect oil pressure sensor connector. Oil pressure sensor is located on right side of engine near distributor (2.5L) or camshaft position sensor (4.0L) and has a Black 3-pin connector. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. Measure voltage between ground and Violet/Orange wire at oil pressure sensor harness connector. If voltage is more than 4.9 volts, go to next step. If voltage is 4.9 volts or less, repair open in Violet/Orange wire between oil pressure sensor and PCM.
4. Turn ignition off. Disconnect Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Gray/Yellow wire at oil pressure 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 Gray/Yellow wire between oil pressure sensor and PCM.
5. Measure resistance between Gray/Yellow and Black/Light Blue wires at oil pressure sensor harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Gray/Yellow and Black/Light Blue wires are shorted together. Repair wiring as necessary.
6. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Using scan tool, read oil pressure sensor voltage. If voltage is more than 4.5 volts, replace oil pressure sensor. If voltage is 4.5 volts or less, replace PCM.

1. Turn ignition on. Using scan tool, read oil pressure sensor voltage. If voltage is 4.8 volts or less, go to step 6. If voltage is more than 4.8 volts, go to next step.
2. Turn ignition off. Disconnect oil pressure sensor connector. Oil pressure sensor is located on right side of engine near distributor (2.5L) or camshaft position sensor (4.0L) and has a Black 3-pin connector. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Black/Light Blue wire between oil pressure sensor harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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.
3. Measure resistance of Gray/Yellow wire between oil pressure sensor harness connector and terminal B23 at PCM C2 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Gray/Yellow wire.
4. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. Measure voltage between ground and Gray/Yellow wire at oil pressure 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/Yellow wire between oil pressure sensor and PCM.
5. Turn ignition off. Connect a jumper wire between Gray/Yellow and Black/Light Blue wires at oil pressure sensor harness connector. Turn ignition on. Using scan tool, read oil pressure sensor voltage. If voltage is one volt or more, replace PCM. If voltage is less than one volt, replace oil pressure sensor.
6. Turn ignition off. Visually inspect related connectors and wiring harness for damage. Repair connectors and wiring harness as necessary. Check for any related technical service bulletins that may apply. Start engine. Using scan tool, monitor oil pressure sensor voltage while wiggling oil pressure sensor wiring harness and connector. Oil pressure sensor is located on right side of engine near distributor (2.5L) or camshaft position sensor (4.0L) and has a Black 3-pin connector. If oil pressure sensor voltage changes while wiggling wiring harness, repair wiring harness or connector 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, read DTCs. If GOOD TRIP counter is displayed for DTC P0551 and displayed count is "0", go to next step. If GOOD TRIP counter for DTC P0551 is not displayed or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect P/S pressure switch connector. P/S pressure switch is attached to power steering high pressure hose at pump and has a Black 2-pin connector. Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, measure resistance between ground and Black wire at P/S pressure switch harness connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black wire between P/S pressure switch and ground. Ground connection is located at right rear of engine block.
3. Connect one end of a jumper wire to Dark Blue/Brown wire at P/S pressure switch harness connector. Turn ignition on. Using scan tool, monitor P/S pressure switch. Touch other end of jumper wire to ground several times. If P/S pressure switch state does not change, go to next step. If P/S pressure switch state changes, replace P/S pressure switch.
4. Turn ignition off. Ensure P/S pressure switch connector is still disconnected. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Dark Blue/Brown wire at P/S pressure switch 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/Brown wire between P/S pressure switch and PCM.
5. Measure resistance of Dark Blue/Brown wire between P/S pressure switch harness connector and terminal A12 at PCM C1 connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Blue/Brown wire.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. 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, no problem is indicated at this time. Check for any related technical service bulletins that may apply. Test is complete.

Turn ignition on. Using scan tool, read DTCs. If DTC P0601: INTERNAL CONTROLLER FAILURE is present, replace PCM. If DTC P0601: INTERNAL CONTROLLER FAILURE is not present, no problem is indicated at this time. Test is complete.

1. Turn ignition on. Using scan tool, actuate A/C clutch relay. A/C clutch relay is located in Power Distribution Center (PDC). PDC is located in engine compartment, next to battery. see scheme 3 If A/C clutch relay clicks, go to next step. If A/C clutch relay does not click, go to step 4.
2. Ensure ignition is on, with engine off. Wiggle wiring harness from A/C clutch relay to PCM while actuating A/C clutch relay. PCM is located on firewall in right rear corner of engine compartment. If A/C clutch relay stops clicking at any time while wiggling wiring harness, repair wiring harness where wiggling caused A/C clutch relay to stop clicking. If A/C clutch relay does not stop clicking at any time while wiggling wiring harness, go to next step.
3. Turn ignition off. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, no problem is indicated at this time. Test is complete.
4. Turn ignition off. Remove A/C clutch relay. A/C clutch relay is located in Power Distribution Center (PDC). PDC is located in engine compartment, next to battery. see scheme 3 Measure voltage between ground and terminal A6 (Red/Light Green wire) at A/C clutch relay socket in PDC. see scheme 3 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open in power circuit to A/C clutch relay (Red/Light Green wire). See WIRING DIAGRAMS article.
5. Measure resistance between terminals No. 85 and 86 at A/C clutch relay. (Scheme 32) If resistance is 50-90 ohms, go to next step. If resistance is not 50-90 ohms or more, replace A/C clutch relay.
6. Ensure ignition is off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Dark Blue/Orange wire between terminal A8 at A/C clutch relay socket in PDC and terminal C1 at PCM C3 harness connector. see scheme 3and (Scheme 28). 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 Dark Blue/Orange wire at terminal C1 at PCM C3 harness connector. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Orange wire. If resistance is 5 ohms or more, go to next step.
8. At this time, PCM is assumed to be defective. Replace PCM.

Note. 1/1 HO2S may also be referred to as an upstream oxygen sensor. On 2.5L and 4.0L Federal models, 1/1 HO2S is located in exhaust downpipe in front of catalytic converter. On 4.0L Calif. models, 1/1 HO2S is located in front exhaust manifold.

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 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.
5. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 1/1 HO2S harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/1 HO2S ground circuit (Black/Light Blue wire) between 1/1 HO2S and PCM.
6. Turn ignition off. Using a voltmeter, backprobe Black/Dark Green wire between 1/1 HO2S harness connector and terminal A24 at PCM C1 harness connector. (Scheme 28) Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to step 13. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/1 HO2S signal circuit (Black/Dark Green wire) between 1/1 HO2S and PCM.
7. Turn ignition off. Disconnect 1/1 HO2S connector. Turn ignition on. Using scan tool, actuate O2 HEATER TEST. Measure voltage between ground and Orange/Dark Green 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 (Orange/Dark Green wire) to 1/1 HO2S heater. See WIRING DIAGRAMS.
8. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/Orange wire between 1/1 HO2S harness connector and terminal C8 at PCM C3 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Orange wire.
9. Ensure ignition is off. Reconnect PCM connectors. Using a voltmeter, backprobe Black/Dark Green wire between 1/1 HO2S harness connector and terminal A24 at PCM C1 harness connector. (Scheme 28) Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/1 HO2S signal circuit (Black/Dark Green wire) between 1/1 HO2S and PCM.
10. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 1/1 HO2S harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 1/1 HO2S ground circuit (Black/Light Blue wire) between 1/1 HO2S and PCM.
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.

Note. 2/1 HO2S is located on rear exhaust manifold. 2/1 HO2S may also be referred to as a upstream oxygen sensor.

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. Start engine and allow it to idle. 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. 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.
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. 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 A4 at PCM C1 harness connector. (Scheme 28) Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 2/1 HO2S ground circuit (Black/Light Blue wire) between 2/1 HO2S and PCM.
6. Turn ignition off. Using a voltmeter, backprobe Light Green/Red wire between 2/1 HO2S harness connector and terminal A26 at PCM C1 harness connector. (Scheme 28) Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to step 13. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 2/1 HO2S signal circuit (Light Green/Red wire) between 2/1 HO2S and PCM.
7. Turn ignition off. Disconnect 2/1 HO2S connector. Turn ignition on. Using scan tool, actuate O2 HEATER TEST. Measure voltage between ground and Orange/Dark Green 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, open in power circuit (Orange/Dark Green wire) to 1/1 HO2S heater. See WIRING DIAGRAMS.
8. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/White wire between 21/1 HO2S harness connector and terminal C16 at PCM C3 harness connector. (Scheme 28) 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. Ensure ignition is off. Reconnect PCM connectors. Using a voltmeter, backprobe Light Green/Red wire between 2/1 HO2S harness connector and terminal A26 at PCM C1 harness connector. (Scheme 28) Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 2/1 HO2S signal circuit (Light Green/Red wire) between 2/1 HO2S and PCM.
10. Turn ignition off. Using a voltmeter, backprobe Black/Light Blue wire between 2/1 HO2S harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) Start engine and ensure engine is at normal operating temperature. If voltage is less than 0.1 volt, go to next step. If voltage is 0.1 volt or more, repair poor connection causing high resistance on 2/1 HO2S ground circuit (Black/Light Blue wire) between 2/1 HO2S and PCM.
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.

Start engine and allow it to idle. Road test vehicle under normal operating conditions for 20 minutes. Using scan tool, read engine coolant temperature. 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. Fuel pump relay is located in Power Distribution Center (PDC). PDC is located in engine compartment, next to battery. see scheme 3 If fuel pump relay clicks, go to next step. If fuel pump relay does not click, go to step 4.
2. Ensure ignition is on. Wiggle wiring harness from fuel pump relay to Powertrain Control Module (PCM) while actuating fuel pump relay. PCM is located on firewall in right rear corner of engine compartment. If fuel pump relay stops clicking at any time while wiggling wiring harness, repair wiring harness where wiggling caused fuel pump relay to stop clicking. If fuel pump relay does not stop clicking at any time while wiggling wiring harness, go to next step.
3. Turn ignition off. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, no problem is indicated at this time. Test is complete.
4. Remove fuel pump relay from PDC. Turn ignition on. Measure voltage between ground and terminal C10 (Dark Green/Black wire) at fuel pump relay socket in PDC. see scheme 3 If voltage is more than 10 volts, turn ignition off and go to next step. If voltage is 10 volts or less, repair open in fused ignition switch output circuit (Dark Green/Black wire) between fuel pump relay and PDC.
5. Using an ohmmeter, measure resistance between terminals No. 85 and 86 at fuel pump relay. (Scheme 32) 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. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown wire between terminal C8 at fuel pump relay socket in PDC and terminal C19 at PCM C3 harness connector. see scheme 3and (Scheme 28). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown wire between fuel pump relay and PCM.
7. Measure resistance between ground and terminal C19 (Brown 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 wire between fuel pump relay and PCM.
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 step 3 . If GOOD TRIP counter for DTC P1294 is not displayed or displayed count is not "0", go to next step.
2. Check FREEZE FRAME data on scan tool to determine the conditions when DTC was set. Attempt to duplicate conditions for added diagnosis. Recheck for DTCs. If DTC P1294: TARGET IDLE NOT REACHED reoccurs, go to next step. If DTC P1294: TARGET IDLE NOT REACHED does not reoccur, conditions to set DTC are not present at this time. Test is complete.
3. Turn ignition on. Ensure throttle plate is fully closed against stop. Check throttle plate and linkage for binding. Repair throttle plate and linkage as necessary. If throttle plate and linkage are okay, go to next step.
4. Start engine and allow it to idle for 60 seconds. If vehicle is equipped with A/T, apply brakes and shift gear selector to Drive. Using scan tool, read TARGET IDLE and ENGINE RPM. If engine RPM is within 100 RPM of target idle, go to next step. If engine RPM is not within 100 RPM of target idle, go to step 8 .
5. Turn ignition off. Using scan tool, go to SYSTEM TESTS and select IAC WIGGLE TEST. Idle speed should vary while in wiggle test mode. If idle speed raises and lowers during wiggle test, go to next step. If idle speed does not raise and lower during wiggle test, perform «DTC P0505: IDLE AIR CONTROL MOTOR CIRCUITS»(ref-12240-S02798547192000121500000) test.
6. Start engine and allow it to idle. Using scan tool, go to SYSTEM TESTS and select IAC WIGGLE TEST. While wiggling wiring harness between IAC motor and PCM, monitor engine RPM. IAC motor is located on throttle body. PCM is located on firewall in right rear corner of engine compartment. If IAC motor stops operating at any time while wiggling wiring harness, repair wiring harness where wiggling caused IAC motor to stop operating. If IAC motor does not stop operating, go to next step.
7. Turn ignition off. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, no problem is indicated at this time. Test is complete. NOTE: The following step is invalid if engine has any vacuum leaks.
8. Start engine and allow it to idle. Check engine, brake booster and vacuum hoses for leaks. Ensure Closed Crankcase Ventilation (CCV) system is functioning properly. Repair vacuum leaks as necessary. If CCV system is okay and no vacuum leaks exist, go to next step.
9. Start engine and allow it to idle for 60 seconds. Using scan tool, go to SYSTEM TESTS and select IAC WIGGLE TEST. Idle speed should vary while in wiggle test mode. If idle speed raises and lowers during wiggle test, go to next step. If idle speed does not raise and lower during wiggle test, perform «DTC P0505: IDLE AIR CONTROL MOTOR CIRCUITS»(ref-12240-S02798547192000121500000) test.
10. Turn ignition off. Remove throttle body. While holding throttle open, spray entire throttle body bore with appropriate cleaner. Using a soft scuff pad, clean throttle body bore and throttle plate. Using compressed air, dry throttle body. Install throttle body. Start engine and allow it to idle. Using scan tool, actuate MIN AIRFLOW. If engine speed is less than 550 RPM, replace throttle body. If engine speed is 550 RPM or more, no problem is indicated at this time. Test is complete.

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. see scheme 10or see scheme 11. 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 Orange 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 (Orange 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 Powertrain Control Module (PCM) connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Orange 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 (Orange 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. see scheme 10or see scheme 11. 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, read DTCs. If DTC P0107: MAP SENSOR VOLTAGE TOO LOW is present, repair DTC P0107 before continuing with this test. See «DTC P0107: MAP SENSOR VOLTAGE TOO LOW»(ref-12240-S37618742672000121500000). If DTC P0107: MAP SENSOR VOLTAGE TOO LOW is not present, go to next step.
2. Turn ignition on, with engine off. Using scan tool, erase DTCs. Start engine and allow it to idle for 30 seconds. Using scan tool, read DTCs. If DTC P1297: NO CHANGE IN MAP FROM START TO RUN is present, go to next step. If DTC P1297: NO CHANGE IN MAP FROM START TO RUN is not present, go to step 6.
3. Turn ignition off. Disconnect MAP sensor connector. see scheme 10or see scheme 11. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Orange wire between MAP sensor harness connector and terminal A17 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
4. Turn ignition off. Remove MAP sensor and inspect sensor vacuum port for restrictions. Repair any restrictions as necessary. If no restrictions exist, go to next step.
5. At this time, MAP sensor is assumed to be defective. Replace MAP sensor.
6. Start engine and allow it to idle. Using scan tool, set engine speed to 1500 RPM and read MAP sensor voltage. Wiggle connectors and wiring harness from MAP sensor to PCM. see scheme 10or see scheme 11. PCM is located on firewall in right rear corner of engine compartment. If engine stalls or voltage becomes erratic while wiggling wiring harness, repair connectors and wiring harness as necessary where wiggling caused engine to stall or voltage to become erratic. If engine does not stall and voltage does not become erratic, go to next step.
7. Ensure engine speed is still set to 1500 RPM. Using scan tool, monitor engine vacuum while snapping throttle open and closed. If vacuum drops rapidly to less than one in. Hg, no problem is indicated at this time. Test is complete. If vacuum does not drop rapidly to less than one in. Hg, go to next step.
8. Turn ignition off. Remove MAP sensor and inspect sensor vacuum port for restrictions. Repair any restrictions as necessary. Inspect intake manifold or throttle body vacuum port and hose for restrictions. Repair any restrictions as necessary. If no restrictions exist, go to next step.
9. At this time, MAP sensor is assumed to be defective. Replace MAP sensor.

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 7.
2. Turn ignition off. Remove ASD relay. ASD relay is located in Power Distribution Center (PDC). PDC is located in engine compartment, next to battery. see scheme 3 Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Measure resistance of Dark Blue/Yellow wire between terminal A11 at ASD relay socket in PDC and terminal C3 at PCM C3 harness connector. see scheme 3and (Scheme 28). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Blue/Yellow wire.
3. Turn ignition on. Measure voltage between ground and terminal A13 (Dark Blue wire) at ASD relay socket in PDC. see scheme 3 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, check for repair open in Dark Blue wire between ASD relay and fuse block. Also check fuse No. 12 (10-amp) in fuse block. Fuse block is located behind glove box. Repair wiring or replace fuse as necessary.
4. Turn ignition off. Ensure PCM is disconnected. Measure resistance between ground and terminal C3 (Dark Blue/Yellow wire) at PCM C3 harness connector. (Scheme 28) 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 ASD relay and PCM.
5. Measure resistance between terminals No. 85 and 86 at ASD relay. (Scheme 32) If resistance is not 50-80 ohms, replace ASD relay. If resistance is 50-80 ohms, go to next step.
6. At this time, PCM is assumed to be defective. Replace PCM.
7. 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 wiring harness from ASD relay to PCM while monitoring scan tool display. PCM is located on firewall in right rear corner of engine compartment. 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 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 in engine compartment, next to battery. see scheme 3 Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Dark Green/Pink wire between terminal A14 at ASD relay socket in PDC and terminal C12 at PCM C3 connector. see scheme 3and (Scheme 28). If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in Dark Green 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). PDC is located in engine compartment, next to battery. see scheme 3 Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Dark Green/Pink wire between terminal A14 at ASD relay socket in PDC and terminal C12 at PCM C3 connector. see scheme 3and (Scheme 28). If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open in Dark Green wire.
6. Measure voltage between ground and terminal A15 (Red/White wire) at ASD relay socket in PDC. see scheme 3 If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, repair open fused B+ output circuit (Red/White wire) between ASD relay and PDC.
7. Install a known-good ASD relay and attempt to start engine. If engine does not start, go to next step. If engine starts, replace original ASD relay.
8. 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 and allow it to idle. Wiggle wiring harness from ASD relay to PCM. PCM is located on firewall in right rear corner of engine compartment. Using scan tool, read DTCs. If DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM returns or engine stalls, repair wiring harness as necessary. If DTC P1389: NO ASD RELAY OUTPUT VOLTAGE AT PCM does not return and engine does not stall, no problem is indicated at this time. Test is complete. Check for any related technical service bulletins that may apply.

Note. CMP or CKP sensor signal loss can be detected by an RPM change, DTC or by observing oscilloscope pattern. Refer to manufacturer's operation manual for instructions in use of oscilloscope and procedure for pattern analysis.

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. Start engine and allow it to idle. Ensure engine is at normal operating temperature. Using scan tool, select MISCELLANEOUS, then SET SYNC. Ensure engine is at normal operating temperature. Observe ACTUAL SYNC SETTING on scan tool display. If scan tool displays IN RANGE, go to next step. On 2.5L, if scan tool does not display IN RANGE, loosen distributor hold-down clamp bolt and rotate distributor until reading is as close to zero degrees as possible, and IN RANGE message is displayed. On 4.0L, if scan tool does not display IN RANGE, loosen oil pump drive hold-down clamp bolt and rotate oil pump drive until reading is as close to zero degrees as possible, and IN RANGE message is displayed. On all models, tighten hold-down clamp bolt to 17 ft. lbs. (23 N.m).
3. Turn ignition off. Using oscilloscope's voltage lead, backprobe Tan/Yellow wire at CMP sensor harness connector. Start engine and observe oscilloscope pattern. If CMP sensor signal pattern is not consistent, go to next step. If CMP sensor signal pattern is consistent, go to step 7.
4. Turn ignition off. Disconnect CMP sensor connector. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Visually inspect connectors for corroded, damaged, pushed-out or miswired terminals. Repair connectors as necessary. If connectors are okay, go to next step.
5. On 2.5L, remove distributor cap and rotor. Inspect pulse ring for damage or misalignment, and verify pulse ring rotates when engine is cranked. If pulse ring is damaged, repair or replace distributor and/or pulse ring as necessary. If pulse ring is okay, go to next step. On 4.0L, remove CMP sensor from oil pump drive shaft. Inspect pulse ring for damage or misalignment, and verify pulse ring rotates when engine is cranked. If pulse ring is damaged, repair or replace oil pump drive shaft and/or pulse ring as necessary. See IGNITION SYSTEM in REMOVAL, OVERHAUL & INSTALLATION article. If pulse ring is okay, go to next step.
6. At this time, CMP sensor is assumed to be defective. Replace CMP sensor.
7. Turn ignition off. Using oscilloscope's voltage lead, backprobe Gray/Black wire at CKP sensor harness connector. CKP sensor is mounted to left side of transmission bellhousing. CKP sensor connector is located on top of intake manifold, near firewall. Start engine and observe oscilloscope pattern. If CKP sensor signal pattern is not consistent, go to next step. If CKP sensor signal pattern is consistent, go to step 11.
8. Turn ignition off. Disconnect CKP sensor connector. Visually inspect connector for corroded, damaged, pushed-out or miswired terminals. Repair connector as necessary. If connector is okay, check if CKP sensor mounting bolts/nuts are tight. Tighten mounting bolts/nuts as necessary. See TORQUE SPECIFICATIONS in REMOVAL, OVERHAUL & INSTALLATION article. If mounting bolts/nuts are tight, go to next step.
9. Turn ignition off. Remove CKP sensor. Inspect notches on flywheel/drive plate for damage or debris. On 2.5L, flywheel/drive plate contains 2 sets of notches which contain 4 slots each on outer edge of flywheel/drive plate. On 4.0L, flywheel/drive plate contains 3 sets notches which contain 4 slots in each set. On all models, check slotted areas for damage or any foreign debris. If slotted areas on flywheel/drive plate are okay and no debris exists, go to next step. If slotted areas on flywheel/drive plate are damaged or debris exists, repair or replace flywheel/drive plate as necessary.
10. At this time, CKP sensor is assumed to be defective. Replace CKP sensor.
11. Turn ignition off. Visually inspect CMP sensor and/or CKP sensor connector for corroded, damaged, pushed-out or miswired terminals. Repair connector as necessary. If connector is okay, check if CMP sensor and/or CKP sensor mounting bolts/nuts are tight. Tighten mounting bolts/nuts as necessary. See TORQUE SPECIFICATIONS in REMOVAL, OVERHAUL & INSTALLATION article. If mounting bolts/nuts are tight, go to next step.
12. Turn ignition off. Using oscilloscope's voltage lead, backprobe terminal A8 (Gray/Black wire) at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine. While monitoring oscilloscope pattern, wiggle wiring harness from CKP sensor to PCM. If CKP sensor signal pattern does not remain consistent while wiggling wiring harness, repair wiring harness where wiggling caused CKP sensor signal pattern to become inconsistent. If CKP sensor signal pattern remains consistent while wiggling wiring harness, go to next step.
13. Turn ignition off. Using oscilloscope's voltage lead, backprobe terminal A18 (Tan/Yellow wire) at PCM C1 harness connector. (Scheme 28) Start engine. While monitoring oscilloscope pattern, wiggle CMP sensor signal circuit from CMP sensor to PCM. If CMP sensor signal pattern is consistent, no problem is indicated at this time. Test is complete. If CMP sensor signal pattern is not consistent, repair wiring harness where wiggling caused oscilloscope pattern to become inconsistent.
14. Turn ignition off. Using oscilloscope's voltage lead, backprobe terminal A18 (Tan/Yellow wire) at PCM C1 harness connector. (Scheme 28) PCM is located on firewall in right rear corner of engine compartment. Start engine. While monitoring oscilloscope pattern, wiggle CMP sensor signal circuit from CMP sensor to PCM. If CMP sensor signal pattern is consistent, go to next step. If CMP sensor signal pattern is not consistent, repair wiring harness where wiggling caused oscilloscope pattern to become inconsistent.
15. Turn ignition off. Visually inspect related wiring harness and connectors. Repair wiring harness and connectors as necessary. If wiring harness and connectors are okay, go to next step.
16. Turn ignition off. Using oscilloscope's voltage lead, backprobe terminal A8 (Gray/Black wire) at PCM C1 harness connector. (Scheme 28) Start engine. While monitoring oscilloscope pattern, wiggle wiring harness from CKP sensor to PCM. If CKP sensor signal pattern does not remain consistent while wiggling wiring harness, repair wiring harness where wiggling caused CKP sensor signal pattern to become inconsistent. If CKP sensor signal pattern remains consistent while wiggling wiring harness, no problem is indicated at this time. Test is complete.

1. 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 3 .
2. 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.
3. Turn ignition off. Disconnect CKP sensor connector. CKP sensor is mounted to left side of transmission bellhousing. CKP sensor connector is located on top of intake manifold, near firewall. Visually inspect CKP sensor wiring harness for damage. Repair wiring harness as necessary. If wiring harness is okay, visually inspect CKP sensor connector for corroded, damaged, pushed-out or miswired terminals. Repair connector as necessary. If connector is okay, ensure CKP sensor is installed properly and mounting bolts/nuts are tight. Tighten mounting bolts/nuts as necessary. See TORQUE SPECIFICATIONS in REMOVAL, OVERHAUL & INSTALLATION article. If mounting bolts/nuts are tight, go to next step.
4. Turn ignition off. Remove CKP sensor. Inspect notches on flywheel/drive plate for damage or debris. On 2.5L, flywheel/drive plate contains 2 sets of notches which contain 4 slots each on outer edge of flywheel/drive plate. On 4.0L, flywheel/drive plate contains 3 sets notches which contain 4 slots in each set. On all models, check slotted areas for damage or any foreign debris. If slotted areas on flywheel/drive plate are okay and no debris exists, go to next step. If slotted areas on flywheel/drive plate are damaged or debris exists, repair or replace flywheel/drive plate as necessary.
5. At this time, CKP sensor is assumed to be defective. Replace CKP sensor.

Note. Replacing PCM will not correct this problem.

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 7.
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 on a bracket mounted at left side of engine compartment. (Scheme 33) 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 and set VENT valve to CLOSED. 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. Turn pump timer off. Disconnect fuel tank-to-EVAP canister purge hose (at EVAP canister) while monitoring gauge on evaporative system testing kit. 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 and VENT valve is set to CLOSED. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED. 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 canister.
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 and VENT valve is set to CLOSED. When gauge reaches 14 in. H2O, set PRESSURE/HOLD valve to CLOSED. Turn pump timer off. Disconnect EVAP purge solenoid hoses while monitoring gauge on evaporative system testing kit. EVAP purge solenoid is located on a bracket mounted at left side of engine compartment. (Scheme 33) If pressure does not decrease when hoses are disconnected from EVAP canister, repair or replace hose/tubes to EVAP purge solenoid as necessary. If pressure decreases when vacuum hoses are disconnected from EVAP canister, go to next step.
5. Inspect pressure hose between EVAP canister and LDP. If pressure hose is okay and is not restricted, go to next step. If pressure hose is defective or restricted, replace pressure hose.
6. At this time, LDP is assumed to be defective. Replace LDP.
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. 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. Go to step 2. 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 P1492 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P1492 or displayed count is not "0", go to step 7.
2. Turn ignition off. Disconnect BTS connector. BTS is located under battery and has a Black 2-pin connector. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Black/Light Blue wire between BTS harness connector and terminal A4 at PCM C1 harness connector. (Scheme 28) 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.
3. Measure resistance of Pink/Yellow wire between BTS harness connector and terminal C15 at PCM C3 harness connector. (Scheme 28) 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 ignition is off. Reconnect PCM connectors. Start engine and allow it to idle. Measure voltage between ground and 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.
5. Turn ignition on. Using scan tool, read AMBIENT/BAT TPM VLT value. Connect a jumper wire between BTS harness connector terminals. Voltage should change from more than 4.5 volts to less than one volt. If voltage is not as specified, go to next step. If voltage is as specified, replace BTS.
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 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 6 .
2. Using scan tool, read AMBIENT/BAT TMP VLT value. Disconnect BTS connector. BTS is located under battery and has a Black 2-pin connector. Voltage should change from less than one volt to more than 4.5 volts. If voltage is not as specified, go to next step. If voltage is as specified, replace BTS.
3. Turn ignition off. Ensure BTS connector is still disconnected. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and Pink/Yellow wire at BTS 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/Yellow wire between BTS and PCM.
4. Measure resistance between Pink/Yellow and Black/Light Blue wires at BTS harness connector. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, Pink/Yellow and Black/Light Blue 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 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 LDP. LDP is located on a bracket mounted at left side of engine compartment. (Scheme 33) Install a vacuum gauge to disconnected vacuum hose. Start engine and observe vacuum gauge. If vacuum gauge reads 13 in. Hg or more, go to next step. If vacuum gauge reads less than 13 in. Hg, repair vacuum leak or vacuum obstruction as necessary.
3. Turn ignition off. Disconnect LDP connector. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Orange wire between LDP harness connector and terminal C14 at PCM C3 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Orange wire.
4. Ensure ignition is off. Reconnect PCM connectors. Turn ignition on. With scan tool in INPUTS/OUTPUTS, read LEAK DETECT SW state. While observing scan tool, connect a jumper wire between positive battery terminal and Orange wire at LDP harness connector. If LEAK DETECT SW state does not change, go to next step. If LEAK DETECT SW state changes, replace LDP.
5. Turn ignition off. Disconnect PCM connectors. Measure resistance between ground and terminal C14 (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 DTC to set do not exist or fault is an intermittent problem. Start engine and allow it to idle. Using scan tool, perform LEAK DETECTION PUMP (LDP) TEST. Using scan tool, monitor LDP switch state while wiggling wiring harness from LDP to PCM. LDP is located on a bracket mounted at left side of engine compartment. (Scheme 33) PCM is located on firewall in right rear corner of engine compartment. If LDP switch state stops toggling while wiggling wiring harness, repair wiring harness where wiggling caused toggling to stop. If LDP switch state does not stop toggling while wiggling wiring harness, go to next step.
8. Turn ignition off. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, go to next step.
9. At this time, conditions for DTC to set do not exist or fault is an intermittent problem. Using scan tool, read and record FREEZE FRAME data. Road test vehicle under conditions in FREEZE FRAME data, paying particular attention to fault setting conditions such as speed, temperature, load and MAP vacuum. Using scan tool, read DTCs. If DTC P1494: LEAK DETECTION PUMP SW OR MECHANICAL FAULT is present, go to step 2. If DTC P1494: LEAK DETECTION PUMP SW OR MECHANICAL FAULT is not present, 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 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 8.
2. Turn ignition off. Disconnect LDP connector. LDP is located on a bracket mounted at left side of engine compartment. (Scheme 33) Inspect connector for damaged pins, corrosion and loose terminals. Repair connector as necessary. If connector is okay, turn ignition on. With a test light connected to ground, probe White/Dark Blue wire at LDP harness connector. If test light illuminates brightly, disconnect test light and go to next step. If test light does not illuminate brightly, repair open in White/Dark Blue wire. See WIRING DIAGRAMS article.
3. Using scan tool, actuate leak detection pump. With a test light connected to positive battery terminal, probe White/Dark Green wire at LDP harness connector. If test light flashes on and off, go to next step. If test light does not flash on and off, go to step 5.
4. At this time, LDP is assumed to be defective. Replace LDP.
5. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance between ground and terminal C10 (White/Dark Green wire) at PCM C3 harness connector. (Scheme 28) 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.
6. Measure resistance of White/Dark Green wire between LDP harness connector and terminal C10 at PCM C3 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in White/Dark Green wire.
7. At this time, PCM is assumed to be defective. Replace PCM.
8. Turn ignition off. Visually inspect related connectors and wiring harness. Repair connectors and wiring harness as necessary. If connectors and wiring harness are okay, go to next step.
9. Turn ignition on. Using scan tool, actuate LDP solenoid. Listen to LDP solenoid while wiggling wiring harness from LDP to PCM. LDP solenoid is located integral to LDP. LDP is located on a bracket mounted at left side of engine compartment. (Scheme 33) PCM is located on firewall in right rear corner of engine compartment. If LDP solenoid stops clicking at any time while wiggling wiring harness, repair wiring harness as necessary where wiggling caused solenoid to stop clicking. If solenoid does not stop clicking, no problem is indicated at this time.

1. Turn ignition on. Using scan tool, read DTCs. If GOOD TRIP counter for DTC P1685 is displayed and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P1685 or displayed count is not "0", go to step 7 .
2. Using scan tool, attempt to communicate with SKIM. If scan tool communicates with SKIM, go to next step. If scan tool does not communicate with SKIM, check for open bus circuits from SKIM. See COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT.
3. Using scan tool, check for SKIM DTCs. If no DTCs are present, go to next step. If any DTCs are present, repair SKIM DTCs before continuing with this test. See BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT.
4. Using scan tool, display Vehicle Identification Number (VIN) that is programmed into PCM. If VIN is programmed into PCM, go to next step. If VIN has not been programmed into PCM, use scan tool and program VIN into PCM and retest.
5. Using scan tool, display VIN that is programmed into PCM. If correct VIN is displayed, go to next step. If correct VIN is not displayed, replace PCM.
6. Turn ignition off. Replace SKIM and program new SKIM. See REMOVAL & INSTALLATION in BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT. Attempt to start engine. Using scan tool, read PCM DTCs. If DTC P1685: INVALID SKIM KEY resets, replace PCM. If DTC P1685: INVALID SKIM KEY does not reset, no problem is indicated at this time. Test is complete.
7. DTC P1685 may have been set if SKIM was disconnected or recently replaced. All customer's ignition keys for this vehicle must be tested at this time. Turn ignition off and remove ignition key. Using another customer key, turn ignition on and attempt to start engine. If engine starts, this usually indicates a good key. Continue using remaining ignition keys. Using scan tool, check for DTCs. If all keys start engine and DTC P1685: INVALID SKIM KEY does not reset, no problem is indicated at this time. Problem may have been an actual theft attempt. Test is complete. If any key does not start engine, replace ignition key that would not start engine. Program new key. See SENTRY KEYS under PROGRAMMING in BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT.

1. Turn ignition on. Using scan tool, check for any PCM DTCs. If DTC P1686: NO SKIM BUS MESSAGE RECEIVED is present, go to next step. If DTC P1686: NO SKIM BUS MESSAGE RECEIVED is not present, go to step 5.
2. Using scan tool, attempt to communicate with SKIM. If scan tool communicates with SKIM, go to next step. If scan tool does not communicate with SKIM, check for open bus circuits from SKIM. See COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT.
3. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Disconnect SKIM 6-pin connector. SKIM is mounted underneath steering column. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Violet/Yellow wire between terminals No. 2 at SKIM harness connector and C30 at PCM C3 harness connector. (Scheme 28)and (Scheme 34). If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Violet/Yellow wire.
4. Turn ignition off. Replace SKIM and program new SKIM. See REMOVAL & INSTALLATION in BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT. Turn ignition on. Using scan tool, clear all PCM and SKIM DTCs. Perform 5 ignition cycles (key on/key off) leaving key on for 90 seconds per key cycle. Using scan tool, read PCM DTCs. If DTC P1686 resets, replace PCM. If DTC P1686 does not reset, no problem is indicated at this time. Test is complete.
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.

Scheme 34

1. Turn ignition on. Using scan tool, clear DTCs. Cycle ignition on and off several times. Using scan tool, check for DTCs. If DTC P1687 is present and set counter on scan tool display equals zero, go to next step. If DTC P1687 is not present, or set counter on scan tool display does not equal zero, go to step 4 .
2. Using scan tool, select BODY system, then ELECTRO/MECH CLUSTER. If scan tool communicates with instrument cluster, go to next step. If scan tool does not communicate with instrument cluster, check for open bus circuits from instrument cluster. See COMMUNICATIONS under SYSTEM TESTS in BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT.
3. Start engine and allow it to idle. Compare actual engine speed with tachometer on instrument cluster. If tachometer indicates correct engine speed, replace PCM. If tachometer does not display correct engine speed, perform instrument cluster self-test. See ONE GAUGE INOPERATIVE under SYSTEM TESTS in BODY CONTROL MODULES - WRANGLER article in ACCESSORIES & EQUIPMENT.
4. Turn ignition off. It is assumed that there is an intermittent problem with wiring harness and/or connectors. Visually inspect all related connectors and wiring harness for any possible problems. Repair wiring or connectors as necessary. Also, check for any related technical service bulletins. If no problems are found, test is complete.

1. Turn ignition on, with engine off. Using scan tool, perform SRI MEMORY TEST. If scan tool displays WRITE REFUSED, go to next step. If scan tool does not display WRITE REFUSED, no problem is indicated at this time. Test is complete.
2. Using scan tool, repeat SRI MEMORY TEST. If scan tool displays WRITE REFUSED, replace PCM. PCM is located on firewall in right rear corner of engine compartment. If scan tool does not display WRITE REFUSED, 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 P1899 and displayed count is "0", go to next step. If GOOD TRIP counter is not displayed for DTC P1899 or displayed count is not "0", go to step 7.
2. Apply parking brake. Using scan tool, monitor PNP switch input state while moving shift lever from Park to 1st position, and then back to Park. If scan tool did not indicate correct gear shift positions, go to next step. If scan tool indicated correct gear positions, no problem is indicated at this time. Test is complete.
3. Turn ignition off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Disconnect PNP connector. PNP is located on side of transmission. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Brown/Light Blue wire between PNP harness connector and terminal A6 at PCM C1 harness connector. (Scheme 28) If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown/Light Blue wire.
4. Measure resistance between ground and Brown/Light Blue wire at PNP 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/Light Blue wire between PNP and PCM.
5. Reconnect PNP connector. Measure resistance between ground and terminal A6 (Brown/Light Blue wire) at PCM C1 harness connector while moving shift lever from Park to 1st position, and then back to Park. (Scheme 28) If resistance does not change from less than 10 ohms to more than 10 ohms, replace PNP. If resistance changes from less than 10 ohms to more than 10 ohms, go to next step.
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 and attempt to duplicate condition that caused DTC to set by paying special attention to DTC set conditions. 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.

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 Anti-Lock Brake System (ABS) module and Air Bag Control Module (ACM). If replacing PCM and vehicle is equipped with a Smart Key Immobilizer Module (SKIM), secret key data must also be updated to enable engine starting.

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 «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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-12240-S09035080152000121500000) . 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 TROUBLE SHOOTING - NO CODES article for diagnosis by symptom.
6. If repaired DTC has reset, proceed to appropriate DTC test. See «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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.

SKIS VERIFICATION TEST

Note. Sentry Key Immobilizer Module (SKIM) will only remain in secured access mode for 60 seconds. If incorrect unique Personal Identification Number (PIN) is entered 3 times, SKIM will be locked for one hour. To unlock SKIM, turn ignition on for one hour. When SKIM is locked, scan tool will display BUS +/- SIGNALS OPEN.

1. Obtain vehicle's unique Personal Identification Number (PIN) assigned to SKIM from vehicle owner or manufacturer. Remove all test equipment and jumper wires. Connect any disconnected components. Go to next step.
2. Connect scan tool to Data Link Connector (DLC). Turn ignition on. Using scan tool, select SKIM MODULE REPLACEMENT. Enter 4-digit PIN number to put SKIM in access mode. Go to next step.
3. Using scan tool, select THEFT ALARM, SKIM, MISCELLANEOUS, then select desired procedure and follow steps displayed on scan tool. If SKIM has been replaced, ensure all keys and remote transmitters to be used with vehicle are programmed into SKIM. Go to next step.
4. Using scan tool, clear Diagnostic Trouble Codes (DTC). Perform 5 ignition cycles (key on/key off) leaving key on for 90 seconds per key cycle. Using scan tool, retrieve DTCs from all modules. If no DTCs exist, system is operating correctly and customer's complaint cannot be duplicated, repair is complete. If any DTCs exist, perform appropriate test. See «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS.

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 Anti-Lock Brake System (ABS) module and Air Bag Control Module (ACM). If replacing PCM and vehicle is equipped with a Smart Key Immobilizer Module (SKIM), secret key data must also be updated to enable engine starting.

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-12240-S09035080152000121500000) . After PCM has been 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 and stays running, test is complete. If engine does not start, check for related technical service bulletins. If necessary, go to TROUBLE SHOOTING - NO CODES article for additional testing.

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 Anti-Lock Brake System (ABS) module and Air Bag Control Module (ACM). If replacing PCM and vehicle is equipped with a Smart Key Immobilizer Module (SKIM), secret key data must also be updated to enable engine starting.

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 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-12240-S09035080152000121500000) . 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 «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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 Anti-Lock Brake System (ABS) module and Air Bag Control Module (ACM). If replacing PCM and vehicle is equipped with a Smart Key Immobilizer Module (SKIM), secret key data must also be updated to enable engine starting.

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-12240-S09035080152000121500000) . 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 «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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 Anti-Lock Brake System (ABS) module and Air Bag Control Module (ACM). If replacing PCM and vehicle is equipped with a Smart Key Immobilizer Module (SKIM), secret key data must also be updated to enable engine starting.

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 «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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-12240-S09035080152000121500000) . 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 «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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 Anti-Lock Brake System (ABS) module and Air Bag Control Module (ACM). If replacing PCM and vehicle is equipped with a Smart Key Immobilizer Module (SKIM), secret key data must also be updated to enable engine starting.

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-12240-S09035080152000121500000) . After PCM has been programmed, go to next step.
2. If any DTCs have not been diagnosed, perform appropriate diagnostic test. See «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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 «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) 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 «DTC MESSAGES & CODES»(ref-12240-S04112110222000121500000) table under DIAGNOSTIC TROUBLE CODE DEFINITIONS. If all DTCs have been diagnosed and repaired, test is complete.