Test Description
The number below refers to the step number on the diagnostic table.
- 2: If the voltage is less than the specified value, the condition is present.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Start the engine. Allow the engine to reach operating temperature. Refer to Scan Tool Data List . Operate the engine at 1,500 RPM for 30 seconds. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter less than the specified value? | 22 mV | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
| 4 | Turn OFF the ignition. Disconnect the heated oxygen sensor (HO2S) 2. Turn ON the ignition, with the engine OFF. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter less than the specified value? | 100 mV | Go to Step 5 | Go to Step 7 |
| 5 | Test the HO2S 2 high signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 6 | |
| 6 | Test the HO2S 2 high signal circuit for a short to the HO2S 2 low signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 10 | Go to Step 9 | |
| 7 | The HO2S 2 may be detecting a lean exhaust condition or may be contaminated. Inspect for the following conditions: NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. A silicon contaminated HO2S 2 Any water intrusion into the HO2S 2 connector An exhaust leak between the HO2S 2 and the engine Any vacuum leaks An inaccurate manifold absolute pressure (MAP) sensor-Refer to DTC P0106. An incorrect fuel pressure-Refer to Fuel System Diagnosis. Any lean fuel injectors-Refer to Fuel Injector Balance Test with Special Tool. Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition? | Go to Step 10 | Go to Step 8 | |
| 8 | Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2. Did you complete the replacement? | Go to Step 10 | ||
| 9 | Replace the engine control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 10 | ||
| 10 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 11 | |
| 11 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
| NOTE |
|---|
| Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. |
DTC P0137
The number below refers to the step number on the diagnostic table.
- 2: If the voltage is more than the specified value, the condition is present.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Start the engine. Allow the engine to reach operating temperature. Refer to Scan Tool Data List . Operate the engine at 1,500 RPM for 30 seconds. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter more than the specified value? | 1,065 mV | Go to Step 4 | Go to Step 3 |
| 3 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
| 4 | Turn OFF the ignition. Disconnect the heated oxygen sensor (HO2S) 2. Turn ON the ignition, with the engine OFF. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter within the specified range? | 400-500 mV | Go to Step 5 | Go to Step 6 |
| 5 | Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 2 harness connector on the vehicle harness side and the low signal circuit of the HO2S 2 harness connector on the vehicle harness side. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter more than the specified value? | 800 mV | Go to Step 8 | Go to Step 7 |
| 6 | IMPORTANT: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S 2 high signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 7 | Is the HO2S 2 voltage parameter less than the specified value? | 10 mV | Go to Step 10 | Go to Step 8 |
| 8 | IMPORTANT: The engine control module (ECM) may be damaged if the heated oxygen sensor (HO2S) low signal circuit is shorted to a voltage source. Test the HO2S 2 low signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition? | Go to Step 15 | Go to Step 9 | |
| 9 | Test the HO2S 2 low circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 12 | |
| 10 | The HO2S 2 may be detecting a rich exhaust condition or may be contaminated. Inspect for the following conditions: NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. A silicon contaminated HO2S 2 Any water intrusion into the HO2S 2 connector Engine oil contaminated with fuel An EVAP canister purge condition An incorrect fuel pressure-Refer to Fuel System Diagnosis. Any rich fuel injectors-Refer to Fuel Injector Balance Test with Special Tool. A leaking fuel pressure regulator-Refer to Fuel System Diagnosis. An inaccurate manifold absolute pressure (MAP) sensor-Refer to Scan Tool Data List. An air intake restriction or collapsed air intake duct Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition? | Go to Step 15 | Go to Step 11 | |
| 11 | Test the for an intermittent and for a poor connection at the HO2S 2. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 13 | |
| 12 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 15 | Go to Step 14 | |
| 13 | Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2. Did you complete the replacement? | Go to Step 15 | ||
| 14 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 15 | ||
| 15 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 16 | |
| 16 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
| IMPORTANT |
|---|
| The sensor may be damaged if the circuit is shorted to a voltage source. |
| IMPORTANT |
|---|
| The engine control module (ECM) may be damaged if the heated oxygen sensor (HO2S) low signal circuit is shorted to a voltage source. |
| NOTE |
|---|
| Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. |
DTC P0138
The number below refers to the step number on the diagnostic table.
- 2: If the voltage changes more than the specified value, the condition is not present.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Start the engine. Allow the engine to reach operating temperature. Refer to Scan Tool Data List . Operate the engine at 1,500 RPM for 30 seconds. Quickly cycle the throttle from closed throttle to wide open throttle 3 times while observing the HO2S 2 voltage parameter with a scan tool. Did the HO2S 2 voltage parameter change more than the specified value? | 200 mV | Go to Step 3 | Go to Step 4 |
| 3 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 4 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | |
| 4 | Turn OFF the ignition. Disconnect the heated oxygen sensor (HO2S) 2. Turn ON the ignition, with the engine OFF. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter above the specified value? | 100 mV | Go to Step 5 | Go to Step 11 |
| 5 | Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 2 harness connector on the engine harness side and a good ground. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter less than the specified value? | 100 mV | Go to Step 6 | Go to Step 7 |
| 6 | Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 2 harness connector on the engine harness side and the low signal circuit of the HO2S 2 harness connector on the engine harness side. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter less than the specified value? | 100 mV | Go to Step 9 | Go to Step 8 |
| 7 | Test the HO2S 2 high signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 | |
| 8 | Test the HO2S 2 low signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 | |
| 9 | Test for an intermittent and for a poor connection at the HO2S 2. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 | |
| 10 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 | |
| 11 | Repair the short between the HO2S 2 high signal circuit and the HO2S 2 heater low control circuit. Did you complete the repair? | Go to Step 14 | ||
| 12 | Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2. Did you complete the replacement? | Go to Step 14 | ||
| 13 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 14 | ||
| 14 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 15 | |
| 15 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
DTC P0140
The number below refers to the step number on the diagnostic table.
- 8: If conditions were not corrected, a worn cam, worn intake or exhaust valves, or other engine mechanical failure may be at fault.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Are any DTCs other than DTC P0171 also set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 | |
| 3 | Install a scan tool. Review the Freeze Frame/Failure Records and record the displayed data for this DTC. Select Fuel Trim Data parameter. Start the engine. Observe the Long Term FT parameter with a scan tool. Is the Long Term FT parameter more than the specified value? | 19% | Go to Step 4 | Go to Diagnostic Aids |
| 4 | Operate the engine at idle. Observe the heated oxygen sensor (HO2S) parameters with a scan tool. Does the scan tool indicate that the values are within the specified range and fluctuating? | 20-900 mV | Go to Step 5 | Go to Step 6 |
| 5 | Turn OFF the engine. Visually and physically inspect the following items: The vacuum hoses for splits, kinks, and proper connections-Refer to Emission Hose Routing Diagram. Properly functioning fuel injectors-Refer to Fuel Injector Coil Test. If fuel pressure is too low, this DTC may set. Refer to Fuel System Diagnosis. Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool). Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | |
| 6 | Turn OFF the engine. Turn ON the ignition, with the engine OFF. Observe the manifold absolute pressure (MAP) sensor pressure parameter with a scan tool. Refer to Altitude vs Barometric Pressure. The MAP sensor pressure should be within the range specified for your altitude. Does the MAP indicate the correct barometric pressure? | Go to Step 7 | Go to DTC P0106 | |
| 7 | Turn OFF the engine. Inspect for the following conditions: The HO2S for proper installation Ensure that the electrical connectors and wires are secured and not contacting the exhaust system. The HO2S signal circuit for an open or a short to ground-Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Fuel System Diagnosis | |
| 8 | Operate the engine at idle. Inspect for the following conditions: Missing, loose, or leaking exhaust components Vacuum leaks at the intake manifold, throttle body, and injector O-rings The air induction system and air intake ducts for leaks The crankcase ventilation system for leaks The evaporative canister purge pipes for obstructions or plugging Did you find and correct the condition? | Go to Step 9 | Go to Symptoms - Engine Mechanical in Engine Mechanical | |
| 9 | IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 | |
| 10 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
| IMPORTANT |
|---|
| After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. |
DTC P0171
The number below refers to the step number on the diagnostic table.
- 8: If conditions were not corrected, a worn cam, worn intake or exhaust valves or other engine mechanical failure may be at fault.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Are any DTCs other than DTC P0172 also set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 | |
| 3 | Install a scan tool. Review the Freeze Frame/Failure Records and record the displayed data for this DTC. Select Fuel Trim Data parameter. Start the engine. Observe the Long Term FT parameter with a scan tool. Is the Long Term FT parameter less than the specified value? | 20% | Go to Step 4 | Go to Diagnostic Aids |
| 4 | Start the engine. Allow the engine to reach operating temperature. Put the transmission in PARK or NEUTRAL position. Turn off all of the accessories. Allow the engine to idle. Observe the Manifold Absolute Pressure (MAP) sensor parameter with a scan tool. Is the MAP sensor parameter within the specified range? | 19-42 kPa | Go to Step 5 | Go to DTC P0106 |
| 5 | Operate the engine at idle. Observe the heated oxygen sensor (HO2S) parameters with a scan tool. Does the scan tool indicate that the values are within the specified range and fluctuating? | 20-900 mV | Go to Step 6 | Go to Step 7 |
| 6 | Turn OFF the engine. Visually and physically inspect the following items: The vacuum hoses for splits, kinks, and proper connections-Refer to Emission Hose Routing Diagram. The air intake duct for being collapsed or restricted The air filter for being dirty or restricted For objects blocking the throttle body Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | |
| 7 | Turn OFF the engine. Inspect for the following conditions: The HO2S for proper installation Ensure that the electrical connectors and wires are secured and not contacting the exhaust system. The HO2S signal circuit for a short to voltage-Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Fuel System Diagnosis | |
| 8 | Inspect for the following: Excessive fuel in the crankcase The evaporative emission (EVAP) control system for proper operation The fuel system for proper operation-Refer to Fuel System Diagnosis. Ensure that all injectors are functioning properly. Refer to Fuel Injector Coil Test. Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool). Did you find and correct the condition? | Go to Step 9 | Go to Symptoms - Engine Mechanical in Engine Mechanical | |
| 9 | IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 10 | |
| 10 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
| IMPORTANT |
|---|
| After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. |
DTC P0172
System Description
The engine control module (ECM) uses information from the crankshaft position (CKP) sensor and the ignition control (IC) module to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the ECM is able to detect individual misfire events. A misfire rate that is high enough can cause the 3-way catalytic converter (TWC) to overheat under certain driving conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for TWC overheating are present. If the ECM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set.
The numbers below refer to the step numbers on the diagnostic table.
- 2: If the actual CKP variation values are not within the learned values, the misfire counters may increment.
- 3: P0300, P0340, and P0341 may all be set by similar conditions.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Start the engine. Allow the engine to idle or operate within the conditions listed in the Freeze Frame/Failure Records. Monitor all of the Misfire counters with the scan tool. Are any of the Misfire Current counters incrementing? | Go to Step 3 | Go to Intermittent Conditions | |
| 3 | Are any DTCs other than P0340 or P0341 set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 4 | |
| 4 | Can any abnormal engine noise be heard? | Go to Symptoms - Engine Mechanical | Go to Step 5 | |
| 5 | Observe the Misfire History Cyl# parameter with a scan tool. Does more than one cylinder indicate a large count value for the Misfire History Cyl# parameter? | Go to Step 6 | Go to Step 8 | |
| 6 | Are the Misfire History Cyl# counts indicated for companion cylinders 1/4 or 2/3? | Go to Step 8 | Go to Step 7 | |
| 7 | Inspect the following components: The vacuum hoses and seals for splits, restrictions, and improper connections-Refer to Emission Hose Routing Diagram. The crankcase ventilation system for vacuum leaks-Refer to Crankcase Ventilation System Inspection/Diagnosis in Engine Mechanical. The engine control module (ECM) grounds for corrosion and loose connections-Refer to Ground Distribution Schematics in Wiring Systems. The exhaust system for restrictions-Refer to Restricted Exhaust in Engine Exhaust. The fuel for contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool). Did you find and correct the condition? | Go to Step 17 | Go to Step 8 | |
| 8 | Turn OFF the ignition. Remove the fuel pump relay. Refer to Relay Replacement (Within an Electrical Center) or Relay Replacement (Attached to Wire Harness) in Wiring Systems. Remove the ignition coil housing assembly, keeping the ignition control (IC) module assembly connected to the harness connector. Refer to Ignition Coil Housing Replacement. IMPORTANT: Not grounding the IC module housing may cause an erratic spark. Connect a jumper wire between the top of the IC module and a good ground. Install the J 36012-A Ignition System Diagnosis Harness. Install a J 26792 Spark Tester on the #1 spark plug jumper wire. Ground the #4 spark plug jumper wire. The #4 wire is the companion to #1. Crank the engine with the remaining spark plug wires connected. Repeat the above steps by installing the spark tester on #4 and grounding #1. Do the same for the #2 and the #3 spark plugs. Ensure the companion wire is grounded. Does the spark tester spark on all cylinders? | Go to Step 9 | Go to Electronic Ignition (EI) System Diagnosis (With Special Tool) or Electronic Ignition (EI) System Diagnosis (Without Special Tool) | |
| 9 | Remove the spark plug from the cylinder that indicated a misfire. Refer to Spark Plug Replacement. Inspect the spark plug. Refer to Spark Plug Inspection. Does the spark plug appear to be OK? | Go to Step 10 | Go to Step 11 | |
| 10 | Exchange the suspected spark plug with another cylinder that is operating properly. Refer to Spark Plug Replacement. Operate the vehicle under the same conditions that the misfire occurred. Did the misfire move with the spark plug? | Go to Step 17 | Go to Step 14 | |
| 11 | Is the spark plug oil or coolant fouled? | Go to Symptoms - Engine Mechanical | Go to Step 12 | |
| 12 | Is the spark plug gas fouled? | Go to Step 15 | Go to Step 13 | |
| 13 | Did the spark plug show any signs of being cracked, worn, or improperly gapped? | Go to Step 16 | Go to Step 14 | |
| 14 | Perform the fuel injector coil test. Refer to Fuel Injector Coil Test. Did you find and correct the condition? | Go to Step 18 | Go to Symptoms - Engine Mechanical | |
| 15 | Perform the fuel system diagnosis. Refer to Fuel System Diagnosis. Did you find and correct the condition? | Go to Step 18 | Go to Symptoms - Engine Mechanical | |
| 16 | Replace or gap the spark plug. Refer to Spark Plug Replacement. Did you complete the action? | Go to Step 18 | ||
| 17 | Replace the faulty spark plug. Refer to Spark Plug Replacement. Did you complete the replacement? | Go to Step 18 | ||
| 18 | Was the customer concern the malfunction indicator lamp (MIL) flashing? | Go to Step 19 | Go to Step 20 | |
| 19 | Operate the vehicle at the specified value for 4 minutes. Operate the vehicle within the Conditions for Running the DTC P0420, as specified in the supporting text. Refer to DTC P0420. Does the DTC run and pass? | 2,500 RPM | Go to Step 20 | Go to DTC P0420 |
| 20 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 21 | |
| 21 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
| IMPORTANT |
|---|
| Not grounding the IC module housing may cause an erratic spark. |
DTC P0300
The number below refers to the step number on the diagnostic table.
- 2: When the ECM enables starter operation, the ECM also initiates the diagnostic test routines for the CKP and camshaft position (CMP) sensors. If the ignition switch is in the start position for more than 4 seconds without the engine cranking, the CKP diagnostics may fail and set this DTC.
| Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Attempt to start the engine. Does the engine crank? | Go to Step 3 | Go to Symptoms - Engine Electrical in Engine Electrical | |
| 3 | Attempt to start the engine. Does the engine start and run? | Go to Step 4 | Go to Step 5 | |
| 4 | Turn OFF the ignition. Disconnect the engine control module (ECM). Measure the resistance between the signal circuit and the low reference circuit of the crankshaft position (CKP) sensor with a DMM. Refer to Circuit Testing in Wiring Systems. Is the resistance within the specified range? | 500-900 ohm | Go to Intermittent Conditions | Go to Step 12 |
| 5 | Crank the engine. Observe the CKP Active Counter parameter with a scan tool. Does the CKP Active Counter increment? | Go to Step 13 | Go to Step 6 | |
| 6 | Test the signal circuit for the following conditions: A short to voltage An open High resistance Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 7 | |
| 7 | Test the low reference circuit for the following conditions: A short to voltage An open High resistance The CKP sensor circuits shorted together Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 8 | |
| 8 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 9 | |
| 9 | Test for an intermittent and for a poor connection at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 | |
| 10 | Remove the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement. Visually inspect the CKP sensor for the following conditions: Physical damage Excessive play or looseness Improper installation Foreign material passing between the CKP sensor and the reluctor wheel Electromagnetic interference in the CKP sensor circuits Did you find and correct the condition? | Go to Step 14 | Go to Step 11 | |
| 11 | Inspect the CKP reluctor wheel for the following conditions: Physical damage Excessive end play or looseness Improper installation Refer to Crankshaft and Bearings Cleaning and Inspection in Engine Mechanical. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 | |
| 12 | Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement. Did you complete the replacement? | Go to Step 14 | ||
| 13 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 14 | ||
| 14 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 15 | |
| 15 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
DTC P0335
The numbers below refer to the step numbers on the diagnostic table.
- 4: If CYL #1 and/or CYL #4 Misfire Counters are incrementing there is a condition within the secondary ignition system that effects the camshaft position signal circuit.
- 6: The ECM supplies 5 volts on the camshaft position signal circuit. This step determines if the ECM is supplying the correct voltage on the circuit.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle | |
| 2 | Start the engine. Observe the CMP Resync Counter with a scan tool. Does the CMP Resync Counter parameter increment and then reset continuously? | Go to Step 3 | Go to Step 4 | |
| 3 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 4 | Go to Diagnostic Aids | |
| 4 | Observe the Misfire Current CYL # 1 and CYL # 4 counters with a scan tool. Is CYL #1 and/or CYL #4 Misfire counters counting up? | Go to DTC P0300 | Go to Step 5 | |
| 5 | Turn OFF the ignition. Disconnect the ignition control module (ICM). Jumper the ICM circuits except for the camshaft position signal circuit from the ICM to the ICM harness connector. Refer to Using Connector Test Adapters in Wiring Systems. Measure the DC duty cycle on the camshaft position signal circuit of the ICM with a DMM. Refer to Circuit Testing in Wiring Systems. Start the engine. Is the Duty Cycle within the specified range? | 45-55% | Go to Step 6 | Go to Step 10 |
| 6 | Turn OFF the ignition. Remove the jumper wires from the ICM. Leave the ICM disconnected. Turn ON the ignition, with the engine OFF. Measure the voltage on the camshaft position signal circuit at the ICM harness connector with a DMM connected to ground. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range? | 4-6 V | Go to Step 8 | Go to Step 7 |
| 7 | Is the voltage above the specified range? | 4-6 V | Go to Step 11 | Go to Step 8 |
| 8 | Turn OFF the ignition. Disconnect the engine control module (ECM). Measure the resistance of the camshaft position signal circuit with a DMM. Refer to Circuit Testing in Wiring Systems. Is the resistance within the specified range? | 0-5 ohm | Go to Step 9 | Go to Step 12 |
| 9 | Leave the ECM and ICM disconnected. Measure the resistance from the camshaft position signal circuit of the ICM harness connector to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the resistance at the specified value? | OL | Go to Step 16 | Go to Step 13 |
| 10 | Turn OFF the ignition. Remove the ICM from the ignition coil housing. Refer to Ignition Control Module Replacement. Remove the interconnect from between the ignition coil housing and the ICM. Inspect the interconnect for a poor connection at the coil housing and at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 14 | |
| 11 | Test the camshaft position signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems Did you find and correct the condition? | Go to Step 18 | Go to Step 16 | |
| 12 | Test the camshaft position signal circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 16 | |
| 13 | Test the camshaft position signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 16 | |
| 14 | Test for an intermittent and for a poor connection at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 15 | |
| 15 | Replace the ICM. Refer to Ignition Control Module Replacement. Did you complete the replacement? | Go to Step 18 | ||
| 16 | Test for an intermittent and for a poor connection at the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 18 | Go to Step 17 | |
| 17 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 18 | ||
| 18 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 19 | |
| 19 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
DTC P0340
Scheme 53
The number below refers to the step number on the diagnostic table.
- 3: This step determines if DTC P0341 is the result of a hard malfunction or an intermittent condition.
| Step | Action | Values | Yes | No |
|---|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views | ||||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | |
| 2 | Install a scan tool. Turn on the ignition, with the engine OFF. Are any other DTCs set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 | |
| 3 | Start the engine. Allow the engine to idle. Observe the CMP Resync Counter with the scan tool. Does the CMP Resync Counter increment to 14, then reset to 0 continuously? | Go to Diagnostic Aids | Go to Step 4 | |
| 4 | Observe the Misfire Counter current CYL #1 and #4 counters with a scan tool. Is cylinder # 1 and/or # 4 Misfire Counters counting up? | Go to DTC P0300 | Go to Step 5 | |
| 5 | Turn ON the ignition, with the engine OFF. Disconnect the ignition control module (ICM). Measure the voltage from the camshaft position (CMP) signal circuit at the ICM harness connector to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range? | 4-6 V | Go to Step 6 | Go to Step 7 |
| 6 | Observe the CMP Resync Counter with a scan tool. Crank the engine. Does the CMP Resync Counter count up without resetting to 0? | Go to Step 8 | Go to Step 10 | |
| 7 | Test the CMP signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | |
| 8 | Test for an intermittent and for a poor connection at the ICM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 | |
| 9 | Replace the ICM. Refer to Ignition Control Module Replacement. Did you complete the replacement? | Go to Step 12 | ||
| 10 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 | |
| 11 | Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 12 | ||
| 12 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 | |
| 13 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK | |
DTC P0341
The number below refers to the step number on the diagnostic table.
- 6: This step includes inspections for conditions that can cause the TWC to appear degraded. Before you proceed with this table, repair any conditions that you find.
| Step | Action | Yes | No |
|---|---|---|---|
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Observe the DTC information on the scan tool. Are there any other component DTCs set? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 3 |
| 3 | Allow the engine to reach operating temperature. Ensure Closed Loop operation is achieved. Increase the engine speed to 1,500 RPM for 1 minute. Return the engine to a stabilized idle. Monitor the heated oxygen sensor (HO2S) 1 and HO2S 2 for the applicable bank. Is the HO2S 2 voltage parameter as active as the HO2S 1 voltage parameter for the applicable bank? | Go to Step 5 | Go to Step 4 |
| 4 | Clear the DTCs with a scan tool. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did DTC P0420 set? | Go to Step 5 | Go to Diagnostic Aids |
| 5 | IMPORTANT: Verify that the three-way catalytic converter (TWC) is a high quality part that meets the OEM specifications. Visually and physically inspect the TWC for the following conditions: Dents or damage Severe discoloration caused by excessive temperatures Holes or punctures Internal rattles caused by a damaged catalyst element Did you find a condition? | Go to Step 9 | Go to Step 6 |
| 6 | Visually inspect the exhaust system for the following conditions: Leaks-Refer to Exhaust Leakage in Engine Exhaust. Physical damage Loose or missing hardware The HO2S 2 for proper torque Did you find and correct the condition? | Go to Step 10 | Go to Step 7 |
| 7 | Visually inspect the catalyst monitor HO2S 2 for the following conditions: The pigtail and wiring harness making contact with the exhaust or any good ground Road damage Did you find a condition? | Go to Step 8 | Go to Step 9 |
| 8 | Replace the HO2S 2 sensor. Refer to Heated Oxygen Sensor Replacement - Position 2. Did you complete the replacement? | Go to Step 10 | |
| 9 | CAUTION: Refer to Road Test Caution in Cautions and Notices. IMPORTANT: A new catalyst may fail this test due to out-gassing of the internal matting. If this occurs, operate the vehicle at highway speeds for approximately one hour and retest. IMPORTANT: Locate and repair the cause of the TWC failure before installing the replacement converter. Refer to Diagnostic Aids. Replace the TWC. Refer to Catalytic Converter Replacement (L61) or Catalytic Converter Replacement (LSJ) in Engine Exhaust.Did you complete the replacement? | Go to Step 10 | |
| 10 | Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 11 |
| 11 | Observe the Capture Info with a scan tool. Are there any DTCs that you have not diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
| IMPORTANT |
|---|
| Verify that the three-way catalytic converter (TWC) is a high quality part that meets the OEM specifications. |
| CAUTION |
|---|
| Refer to Road Test Caution in Cautions and Notices. |
| IMPORTANT |
|---|
| A new catalyst may fail this test due to out-gassing of the internal matting. If this occurs, operate the vehicle at highway speeds for approximately one hour and retest. |
| IMPORTANT |
|---|
| Locate and repair the cause of the TWC failure before installing the replacement converter. Refer to Diagnostic Aids. |
DTC P0420
This diagnostic tests the evaporative emission (EVAP) system for a small leak when the key is turned OFF and the correct conditions are met.
Heat from the exhaust system is transferred into a vehicle fuel tank while the vehicle is operating. When the vehicle is turned OFF and the EVAP system is sealed, a change in the fuel tank vapor temperature occurs, which results in corresponding pressure changes in the fuel tank vapor space. This change is monitored by the control module using the fuel tank pressure sensor input. The control module then makes a judgement on the integrity of the system. With a 0.51 mm (0.02 in) leak in the system, the amount of pressure change observed is significantly less than that of a sealed system.
If the control module detects a pressure change less than a calibrated amount, DTC P0442 sets.
The numbers below refer to the step numbers on the diagnostic table.
- 3: Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
- 5: This step verifies that repairs are complete and that no other condition is present.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Refer to the J 41413-200 Evaporative Emission System Tester (EEST) operation manual for detailed instructions. Turn OFF the ignition. Using the J 41415-40 Fuel Tank Cap Adapter, connect the J 41413-200 to the vehicle filler neck. Use the flow meter on the J 41413-200 to determine if there is a leak greater than 0.51 mm (0.020 in) in the EVAP system. Compare the flow meter's stable floating indicator position to the red flag. Is the floating indicator below the red flag? | Go to Diagnostic Aids | Go to Step 3 |
| 3 | IMPORTANT: Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. Turn OFF the ignition. Using the J 41415-40 , connect the J 41413-200 to the vehicle filler neck. Turn ON the ignition, with the engine OFF. Seal the system and apply smoke to the system until smoke is visible at the J 41413-VLV . Remove the J 41413-VLV once smoke is observed. Continue to introduce smoke into the EVAP system for an additional 60 seconds. Inspect the entire EVAP system for exiting smoke with a High Intensity White Light. Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? | Go to Step 5 | Go to Step 4 |
| 4 | Disconnect the J 41415-40 from the fuel fill pipe. Install the fuel fill cap to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the EVAP service port. Use the remote switch to introduce smoke into the EVAP system. Inspect the entire EVAP system for exiting smoke with a High Intensity White Light. Continue to introduce smoke at 15 second intervals until the leak source has been located. Did you locate and repair a leak source? | Go to Step 5 | Go to Diagnostic Aids |
| 5 | IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Use the flow meter on the J 41413-200 to determine if there is a leak greater than 0.51 mm (0.020 in) in the EVAP system. Compare the flow meter's stable floating indicator position to the red flag. Is the floating indicator below the red flag? | Go to Step 6 | Go to Step 2 |
| 6 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | Go to Step 7 |
| 7 | IMPORTANT: The malfunction indicator lamp (MIL) may remain ON after the repair unless the DTCs are cleared. Clear the DTCs with a scan tool.Did you complete the action? | System OK | |
| IMPORTANT |
|---|
| Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Refer to the J 41413-200 Evaporative Emission System Tester (EEST) operation manual for detailed instructions. |
| IMPORTANT |
|---|
| Ensure that the vehicle underbody temperature is similar to the ambient temperature and allow the surrounding air to stabilize before starting the diagnostic procedure. System flow will be less with higher temperatures. |
| IMPORTANT |
|---|
| Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. |
| IMPORTANT |
|---|
| The malfunction indicator lamp (MIL) may remain ON after the repair unless the DTCs are cleared. |
DTC P0442
Scheme 54
The numbers below refer to the step numbers on the diagnostic table.
- 2: This step tests if the concern is active. The EVAP canister purge solenoid valve is PWM. You should hear a clicking sound when the EVAP canister purge solenoid valve is commanded to 50 percent. The clicking sound should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased.
- 5: This step verifies that the control module is providing ground to the EVAP canister purge solenoid valve.
- 6: This step tests if a ground is constantly being applied to the EVAP canister purge solenoid valve.
| Step | Action | Yes | No |
|---|---|---|---|
| Connector End Views Reference: Engine Control Module (ECM) Connector End Views and Engine Controls Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister purge solenoid valve to 50 percent, then to 0 percent with a scan tool. Does the EVAP canister purge solenoid valve respond to the commanded state? | Go to Step 3 | Go to Step 4 |
| 3 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions |
| 4 | Turn OFF the ignition. Disconnect the EVAP canister purge solenoid valve harness connector. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the EVAP canister purge solenoid valve with a test lamp that is connected to a good ground. Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 |
| 5 | Connect a test lamp between the control circuit of the EVAP canister purge solenoid valve and the ignition 1 voltage circuit of the EVAP canister purge solenoid valve. Command the EVAP canister purge solenoid valve to 0 percent with a scan tool. Does the test lamp illuminate? | Go to Step 8 | Go to Step 6 |
| 6 | Command the EVAP canister purge solenoid valve to 50 percent with a scan tool. Does the test lamp illuminate or pulse when the EVAP purge solenoid valve is commanded to 50 percent? | Go to Step 9 | Go to Step 7 |
| 7 | Test the control circuit of the EVAP canister purge solenoid valve for an open or for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
| 8 | Test the control circuit of the EVAP canister purge solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
| 9 | Inspect for poor connections at the harness connector of the EVAP canister purge solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
| 10 | Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
| 11 | Repair the open or short to ground in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 14 | |
| 12 | Replace the EVAP canister purge solenoid valve. Refer to Evaporative Emission (EVAP) Canister Purge Solenoid Valve Replacement. Did you complete the replacement? | Go to Step 14 | |
| 13 | Replace the electronic control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 14 | |
| 14 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 15 |
| 15 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
DTC P0443
Scheme 55
This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.
| Control Module Command | EVAP Canister Purge Solenoid Valve | EVAP Canister Vent Solenoid Valve |
|---|---|---|
| ON | Open | Closed |
| OFF | Closed | Open |
DTC P0446
The numbers below refer to the step numbers on the diagnostic table.
- 2: Listen for a click when the valve operates. Verify that both the ON and the OFF states are commanded.
- 5: This step verifies that the control module is providing ground to the EVAP canister vent solenoid valve.
- 6: This step tests if the EVAP canister vent solenoid valve control circuit is grounded.
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views | |||
| 1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
| 2 | Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister vent solenoid valve ON and OFF with the scan tool. Do you hear or feel a click from the EVAP canister vent solenoid valve when the valve is commanded ON and OFF? | Go to Step 3 | Go to Step 4 |
| 3 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 4 | Go to Intermittent Conditions |
| 4 | Turn OFF the ignition. Disconnect the EVAP canister vent solenoid valve. Turn ON the ignition, with the engine OFF. Probe the battery positive voltage circuit of the EVAP canister vent solenoid valve with a test lamp connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate? | Go to Step 5 | Go to Step 11 |
| 5 | Connect a test lamp between the control circuit of the EVAP vent solenoid and battery positive voltage circuit of the EVAP canister vent solenoid valve at the EVAP vent valve harness connector. Command the EVAP canister vent solenoid valve ON and OFF with a scan tool. Does the test lamp turn ON and OFF with each command? | Go to Step 9 | Go to Step 6 |
| 6 | Does the test lamp remain illuminated with each command? | Go to Step 8 | Go to Step 7 |
| 7 | Test the control circuit of the EVAP canister vent solenoid valve for a short to voltage or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
| 8 | Test the control circuit of the EVAP canister vent solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 10 |
| 9 | Inspect for poor connections at the harness connector of the EVAP canister vent solenoid valve. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 12 |
| 10 | Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 14 | Go to Step 13 |
| 11 | IMPORTANT: If the fuse is open, inspect all related circuits for a short to ground. Repair the open or short to ground in the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems.Did you complete the repair? | Go to Step 14 | |
| 12 | Replace the EVAP canister vent solenoid valve. Refer to Evaporative Emission (EVAP) Canister Vent Solenoid Valve Replacement. Did you complete the replacement? | Go to Step 14 | |
| 13 | Replace the electronic control module (ECM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 14 | |
| 14 | Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition? | Go to Step 2 | Go to Step 15 |
| 15 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information | System OK |
| IMPORTANT |
|---|
| If the fuse is open, inspect all related circuits for a short to ground. |
DTC P0449
The fuel tank pressure (FTP) sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal voltage varies depending on EVAP system pressure or vacuum. The controller uses this FTP signal to determine atmospheric pressure for use in the engine-off small leak test, DTC P0442. Before using this signal as an atmospheric reference it must first be re-zeroed. If the FTP signal is out of range during the re-zero procedure, this DTC will set.
See also:
• Scan Tool Data List