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Engine Control System - 5.3L - DTC P0137 to P0449: Overview GMC Envoy II

Testing & Diagnostics ~1320 words

Test Description

The number below refers to the step number on the diagnostic table.

  1. 2: If the voltage does not change more than the specified value, the condition is present.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2IMPORTANT: With the engine running, observe the heated oxygen sensor (HO2S) Bank 1 Sensor 1 and HO2S Bank 2 Sensor 1 voltage parameters with a scan tool. The voltage should vary from below 300 mV to above 600 mV. If the voltage is not varying, refer to DTC P0132 or P0152 . 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. While observing the affected HO2S voltage parameter with a scan tool, quickly cycle the throttle from closed throttle to wide open throttle 3 times. Did the HO2S voltage parameter change more than the specified value?200 mVGo to Step 3Go to Step 4
3Observe 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 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the affected HO2S. Turn ON the ignition, with the engine OFF. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter less than the specified value?100 mVGo to Step 6Go to Step 5
5Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter more than the specified value?800 mVGo to Step 7Go to Step 8
6Test the HO2S high signal circuit for a short to ground. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 9
7IMPORTANT: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S high signal circuit for a short to voltage. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 17
8Measure the voltage from the low signal circuit of the HO2S harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage more than the specified value?2 VGo to Step 10Go to Step 11
9Test the HO2S high signal circuit for a short to the HO2S low signal circuit. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 17
10Test the HO2S low signal circuit for a short to voltage. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 17
11Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S harness connector on the engine harness side and a good ground. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter less than the specified value?100 mVGo to Step 12Go to Step 14
12Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S harness connector on the engine harness side and the low signal circuit of the HO2S harness connector on the engine harness side. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter less than the specified value?100 mVGo to Step 15Go to Step 13
13Test the HO2S low signal circuit for an open or high resistance. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 17
14Test the HO2S high signal circuit for an open or high resistance. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 17
15The HO2S 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 Any water intrusion into the HO2S connector An exhaust leak between the HO2S and the engine Any vacuum leaks An incorrect fuel pressure-Refer to Fuel System Diagnosis . Any lean fuel injectors-Refer to Fuel Injector Balance Test with Tech 2 . An inaccurate mass air flow (MAF) sensor-Refer to Scan Tool Data List . Repair any of the above, or similar engine conditions, as necessary. Did you find and correct the condition?Go to Step 20Go to Step 16
16Test for shorted terminals and for poor connections at the HO2S. Refer to the following in Wiring Systems: Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 18
17Test for shorted terminals and for poor connections at the engine control module (ECM). Refer to the following in Wiring Systems: Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 20Go to Step 19
18Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 . Did you complete the replacement?Go to Step 20
19Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 20
20Clear 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 2Go to Step 21
21Observe 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 InformationSystem OK
IMPORTANT
With the engine running, observe the heated oxygen sensor (HO2S) Bank 1 Sensor 1 and HO2S Bank 2 Sensor 1 voltage parameters with a scan tool. The voltage should vary from below 300 mV to above 600 mV. If the voltage is not varying, refer to DTC P0132 or P0152 .
IMPORTANT
The sensor may be damaged if the circuit is shorted to a voltage source.
NOTE
Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices.

DTC P0137 or P0157

The number below refers to the step number on the diagnostic table.

  1. 2: If the voltage does not change more than the specified value, the condition is present.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2IMPORTANT: With the engine running, observe the heated oxygen sensor (HO2S) Bank 1 Sensor 1 and HO2S Bank 2 Sensor 1 voltage parameters with a scan tool. The voltage should vary from below 300 mV to above 600 mV. If the voltage is not varying, refer to DTC P0131 or P0151 . 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. While observing the affected HO2S voltage parameter with a scan tool, quickly cycle the throttle from closed throttle to wide open throttle 3 times. Did the HO2S voltage parameter change more than the specified value?200 mVGo to Step 3Go to Step 4
3Observe 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 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the affected HO2S. Turn ON the ignition, with the engine OFF. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter more than the specified value?800 mVGo to Step 6Go to Step 5
5Measure the voltage from the low signal circuit of the HO2S harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage more than the specified value?2 VGo to Step 7Go to Step 8
6IMPORTANT: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S high signal circuit for a short to voltage. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
7Test the HO2S low signal circuit for a short to voltage. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
8Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S harness connector on the engine harness side and a good ground. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter less than the specified value?100 mVGo to Step 9Go to Step 11
9Remove the jumper wire from the previous step. Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S harness connector on the engine harness side and the low signal circuit of the HO2S harness connector on the engine harness side. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter less than the specified value?100 mVGo to Step 12Go to Step 10
10Test the HO2S low signal circuit for an open or high resistance. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
11Test the HO2S high signal circuit for an open or high resistance. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
12The HO2S 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 Any water intrusion into the HO2S connector Engine oil contaminated with fuel An evaporative emission (EVAP) canister purge condition An incorrect fuel pressure-Refer to Fuel System Diagnosis . Any rich fuel injectors-Refer to Fuel Injector Balance Test with Tech 2 . An inaccurate mass air flow (MAF) 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 17Go to Step 13
13Test for shorted terminals and for poor connections at the HO2S. Refer to the following in Wiring Systems: Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 15
14Test for shorted terminals and for poor connections at the engine control module (ECM). Refer to the following in Wiring Systems: Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 16
15Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 . Did you complete the replacement?Go to Step 17
16Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 17
17Clear 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 2Go to Step 18
18Observe 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 InformationSystem OK
IMPORTANT
With the engine running, observe the heated oxygen sensor (HO2S) Bank 1 Sensor 1 and HO2S Bank 2 Sensor 1 voltage parameters with a scan tool. The voltage should vary from below 300 mV to above 600 mV. If the voltage is not varying, refer to DTC P0131 or P0151 .
IMPORTANT
The sensor may be damaged if the circuit is shorted to a voltage source.
NOTE
Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices.

DTC P0138 or P0158

The number below refers to the step number on the diagnostic table.

  1. 3: If the voltage is varying above and below the specified value, the condition is not present.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Start the engine. Wait 1 minute to allow the heated oxygen sensor (HO2S) heater current to stabilize. Observe the affected HO2S heater current parameter with a scan tool. Is the HO2S heater current parameter within the specified range?0.25-1.375 AGo to Step 3Go to DTC P0135, P0141, P0155, or P0161
3Allow the engine to reach operating temperature. Refer to Scan Tool Data List . Operate the engine at 1,500 RPM for 30 seconds. While observing the affected HO2S voltage parameter with a scan tool, quickly cycle the throttle from closed throttle to wide open throttle 3 times. Did the HO2S voltage parameter change more than the specified value?200 mVGo to Step 4Go to Step 5
4Observe 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 5Go to Intermittent Conditions
5Turn OFF the ignition. Disconnect the affected HO2S. Turn ON the ignition, with the engine OFF. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter more than the specified value?800 mVGo to Step 7Go to Step 6
6Measure the voltage from the high signal circuit of the HO2S harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage more than the specified value?0.2 VGo to Step 8Go to Step 9
7IMPORTANT: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S high signal circuit for a short to voltage. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
8Measure the voltage from the low signal circuit of the HO2S harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage more than the specified value?2 VGo to Step 12Go to Step 10
9Test the HO2S high signal circuit for an open or high resistance. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
10Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S harness connector on the engine harness side and the low signal circuit of the HO2S harness connector on the engine harness side. Observe the HO2S voltage parameter with a scan tool. Is the HO2S voltage parameter less than the specified value?100 mVGo to Step 13Go to Step 11
11Test the HO2S low signal circuit for an open or high resistance. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
12Test the HO2S low signal circuit for a short to voltage. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 14
13Test for shorted terminals and for poor connections at the HO2S. Refer to the following in Wiring Systems: Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 15
14Test for shorted terminals and for poor connections at the engine control module (ECM). Refer to the following in Wiring Systems. Testing for Intermittent Conditions and Poor Connections Connector Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 17Go to Step 16
15Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 . Did you complete the replacement?Go to Step 17
16Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 17
17Clear 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 2Go to Step 18
18Observe 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 InformationSystem OK
IMPORTANT
The sensor may be damaged if the circuit is shorted to a voltage source.

DTC P0140 or P0160

The number below refers to the step number on the diagnostic table.

  1. 7: An evaporative emission (EVAP) canister that is saturated will cause a rich condition.
StepActionValuesYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Are any DTCs other than DTC P0172 or P0175 also set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Install scan tool. Start and idle the engine at the normal operating temperature in Closed Loop. Record the long term fuel trim data. Turn OFF the engine. Turn ON ignition, with the engine OFF. Review the Freeze Frame/Failure Records and record the displayed data for this DTC. Does the scan tool indicate that the long term fuel trim is less than the specified value?17%Go to Step 4Go to Diagnostic Aids
4Operate engine at idle. Observe HO2S parameters with a scan tool. Does the scan tool indicate that the values are within the specified range and fluctuating?200-800 mVGo to Step 5Go to Step 6
5Turn OFF the engine. Visually and physically inspect the following items: The evaporative emission (EVAP) lines and components for damage or blockage-Refer to Evaporative Emissions (EVAP) Hose Routing Diagram . The inlet screen of the mass air flow (MAF) sensor for blockage 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 Inspect for objects blocking the throttle body. Did you find and correct the condition?Go to Step 8Go to Step 7
6Turn OFF the engine. Inspect the heated oxygen sensor (HO2S) for proper installation. Inspect to ensure that the electrical connectors and the wires are secure and not contacting the exhaust system. Test for continuity between the signal circuit and the low reference circuit. Refer to the following in Wiring Systems: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs Did you find and correct the condition?Go to Step 8Go to Fuel System Diagnosis
7Inspect for the following: Excessive fuel in the crankcase Proper operation of the fuel pressure regulator-Refer to Fuel System Diagnosis . All injectors are functioning properly-Refer to Fuel Injector Coil Test . Did you find and correct the condition?Go to Step 8Go to Symptoms - Engine Mechanical in Engine Mechanical
8IMPORTANT: After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim. Turn ON the ignition, with the engine OFF. 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 2Go to Step 9
9Observe 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 InformationSystem OK
IMPORTANT
After repairs, use the scan tool Fuel Trim Reset function in order to reset the Long Term Fuel Trim.

DTC P0172 or P0175

The numbers below refer to the step numbers on the diagnostic table.

  1. 5: This step verifies that the ECM is able to control the fuel injector.
  2. 6: This step tests if a ground is constantly being applied to the fuel injector.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Clear the DTCs with a scan tool. Idle the engine at the normal operating temperature. Monitor the misfire current counters with a scan tool. Are any of the misfire current counters incrementing?Go to Step 4Go to Step 3
3Observe 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 4Go to Diagnostic Aids
4Turn OFF the ignition. Disconnect the injector which displays the highest number of misfire current counters. Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the fuel injector with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 5Go to Step 11
5Connect the J 44603 Fuel Injector Test Lamp between the control circuit of the fuel injector and the ignition 1 voltage circuit of the fuel injector. See Special Tools . Start the engine. Does the test lamp flash?Go to Step 9Go to Step 6
6Does the test lamp remain illuminated?Go to Step 8Go to Step 7
7Test the fuel injector control circuit for the following conditions: A short to voltage An open High resistance Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 10
8Test the fuel injector control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 13
9Test for an intermittent and for a poor connection at the fuel injector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 14Go to Step 12
10Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 14Go to Step 13
11IMPORTANT: The INJ fuse also supplies voltage to the ignition coil modules. If the fuse is open, inspect all related circuits and components for a short to ground. Refer to Circuit Testing . Test the ignition 1 voltage circuit of the fuel injector for: An open High resistance A short to ground Refer to Circuit Testing and Wiring Repairs .Did you find and correct the condition?Go to Step 14
12Replace the fuel injector. Refer to Fuel Injector Replacement . Did you complete the replacement?Go to Step 14
13Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 14
14Clear 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 2Go to Step 15
15Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK
IMPORTANT
The INJ fuse also supplies voltage to the ignition coil modules. If the fuse is open, inspect all related circuits and components for a short to ground. Refer to Circuit Testing .

DTC P0201-P0208

The number below refers to the step number on the diagnostic table.

  1. 2: This step verifies that other DTCs are set.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Are any other DTCs set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to DTC P0121

DTC P0220

The numbers below refer to the step numbers on the diagnostic table.

  1. 2: This step verifies that a condition exists.
  2. 4: The TP sensors share a 5-volt reference circuit. If both DTCs P0122 and P0222 set, test for a condition in the 5-volt reference circuit.
  3. 5: The ECM produces a measurable steady-state amperage that provides the 5-volt reference to the TP sensors. If the amperage on the 5-volt reference circuit is less than 50 mA, test the 5-volt reference circuit for an open or a high resistance.
  4. 6: This step tests the signal 2 circuit of the TP sensor. If the TP sensor 2 voltage parameter is not within 4.8-5.2 volts, test for a condition in the signal 2 circuit.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Turn ON the ignition, with the engine OFF. Observe the TP sensor 2 voltage parameter with a scan tool. Is the voltage less than the specified value?0.275 VGo to Step 4Go to Step 3
3Observe 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 4Go to Diagnostic Aids
4Observe the DTC information with a scan tool. Did DTC P0122 also set?Go to Step 5Go to Step 6
5Turn OFF the ignition. NOTE: Refer to Disengaging Connectors Notice . Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Set up a DMM to test amperage on the 400 mA scale. Measure the amperage from the 5-volt reference circuit of the throttle position (TP) sensor to a good ground. Is the amperage more than the specified value?50 mAGo to Step 9Go to Step 7
6Turn OFF the ignition. NOTE: Refer to Disengaging Connectors Notice . Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the TP sensor and the signal 2 circuit of the TP sensor. Observe the TP sensor 2 voltage parameter with a scan tool. Is the voltage within the specified range?4.8-5.2 VGo to Step 9Go to Step 8
7IMPORTANT: The 5-volt reference circuits are internally connected within the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors. Test the 5-volt reference circuit of the TP sensor and all shared 5-volt reference circuits for an open, a short to ground, or for high resistance. Refer to Circuit Testing and Wiring Repairs .Did you find and correct the condition?Go to Step 13Go to Step 10
8Test the signal 2 circuit of the TP sensor for a short to ground, an open, or for high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 10
9Test for an intermittent and for a poor connection at the throttle body assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 13Go to Step 11
10Test 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 . Did you find and correct the condition?Go to Step 13Go to Step 12
11Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 13
12Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 13
13Clear 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 2Go to Step 14
14Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK
NOTE
Refer to Disengaging Connectors Notice .
NOTE
Refer to Disengaging Connectors Notice .
IMPORTANT
The 5-volt reference circuits are internally connected within the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.

DTC P0222

The numbers below refer to the step numbers on the diagnostic table.

  1. 4: This step verifies that the ECM is providing voltage to the fuel pump relay.
  2. 5: This step tests for an open in the ground circuit to the fuel pump relay.
  3. 6: This step tests if the voltage is constantly being applied to the control circuit of the fuel pump relay.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Turn ON the ignition, with the engine OFF. Command the fuel pump relay ON and OFF with a scan tool. Does the fuel pump relay turn ON and OFF when commanded with a scan tool?Go to Step 3Go to Step 4
3Observe 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 4Go to Testing for Intermittent Conditions and Poor Connections
4Turn OFF the ignition. Remove the fuel pump relay. Turn ON the ignition, with the engine OFF. Probe the control circuit of the fuel pump relay with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems. Command the fuel pump relay ON and OFF with a scan tool. Does the test lamp turn ON and OFF when commanded with a scan tool?Go to Step 5Go to Step 6
5Connect a test lamp between the control circuit of the fuel pump relay and the ground circuit of the fuel pump relay. Command the fuel pump relay ON and OFF with a scan tool. Does the test lamp turn ON and OFF when commanded with a scan tool?Go to Step 9Go to Step 11
6Does the test lamp remain illuminated?Go to Step 8Go to Step 7
7Test the control circuit of the fuel pump relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 14Go to Step 10
8Test the control circuit of the fuel pump relay 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 14Go to Step 10
9Test for an intermittent and for a poor connection at the fuel pump relay. 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 14Go to Step 12
10Test 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 14Go to Step 13
11Test the ground circuit of the fuel pump relay for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 14
12Replace the fuel pump relay. Did you complete the replacement?Go to Step 14
13Replace 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
14Clear 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 2Go to Step 15
15Observe 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 InformationSystem OK

DTC P0230

System Description

The engine control module (ECM) uses information from the crankshaft position (CKP) sensor and the camshaft position (CMP) sensor 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 number below refers to the step number on the diagnostic table.

  1. 2: If the actual CKP variation values are not within the learned values, the misfire counters may increment.
StepActionValuesYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2IMPORTANT: You must perform the Crankshaft Position (CKP) System Variation Learn Procedure before proceeding with this diagnostic table. Refer to CKP System Variation Learn Procedure . 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 3Go to Diagnostic Aids
3Are any other DTCs set?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 4
4Can any abnormal engine noise be heard?Go to Symptoms - Engine MechanicalGo to Step 5
5Does the scan tool indicate that the heated oxygen sensor (HO2S) bank 1 sensor 1 or HO2S bank 2 sensor 1 voltage parameters are below the specified value?200 mVGo to DTC P0131 or P0151Go to Step 6
6Does the scan tool indicate that the HO2S bank 1 sensor 1 or HO2S bank 2 sensor 1 voltage parameters are fixed above the specified value?900 mVGo to DTC P0132 or P0152Go to Step 7
7Inspect the following components: The vacuum hoses and seals for splits, restrictions, and improper connections-Refer to Emission Hose Routing Diagram . The throttle body and intake manifold for vacuum leaks The crankcase ventilation system for vacuum leaks-Refer to Crankcase Ventilation System Inspection/Diagnosis . The engine control module (ECM) grounds for corrosion and loose connections-Refer to Ground Distribution Schematics . The exhaust system for restrictions-Refer to Restricted Exhaust . The fuel for contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (with Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (without Special Tool) . Did you find and correct the condition?Go to Step 19Go to Step 8
8IMPORTANT: An erratic or inconsistent spark is considered a no spark. Turn OFF the ignition. Disconnect the spark plug wire from the spark plug that corresponds to the Misfire Current counters that were incrementing. Refer to Spark Plug Wire Replacement . Install the J 26792 Spark Tester. Start the engine. Does the spark jump the tester gap?Go to Step 10Go to Step 9
9Remove the spark plug wire for the affected cylinders. Refer to Spark Plug Wire Replacement . Inspect the spark plug wire. Refer to Spark Plug Wire Inspection . Measure the resistance of the spark plug wire with a DMM. Is the resistance within the specified value?188-312 ohmGo to Electronic Ignition (EI) System DiagnosisGo to Step 18
10Remove 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 11Go to Step 12
11Exchange 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 17Go to Step 15
12Is the spark plug oil or coolant fouled?Go to Symptoms - Engine MechanicalGo to Step 13
13Is the spark plug gas fouled?Go to Step 16Go to Step 14
14Did the spark plug show any signs of being cracked, worn, or improperly gapped?Go to Step 17Go to Step 15
15Perform the fuel injector coil test. Refer to Fuel Injector Coil Test . Did you find and correct the condition?Go to Step 19Go to Symptoms - Engine Mechanical
16Perform the fuel system diagnosis. Refer to Fuel System Diagnosis . Did you find and correct the condition?Go to Step 19Go to Symptoms - Engine Mechanical
17Replace the faulty spark plug. Refer to Spark Plug Replacement . Did you complete the replacement?Go to Step 19
18Replace the faulty spark plug wires. Refer to Spark Plug Wire Replacement . Did you complete the replacement?Go to Step 19
19Was the customer concern the malfunction indicator lamp (MIL) flashing?Go to Step 20Go to Step 21
20Operate the vehicle at the specified value for 4 minutes. Operate the vehicle within the Conditions for Running the DTC P0420 or P0430 as specified in the supporting text. Refer to DTC P0420 or P0430 . Does the DTC run and pass?2,500 RPMGo to Step 21Go to DTC P0420 or P0430
21Clear 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 2Go to Step 22
22Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK
IMPORTANT
You must perform the Crankshaft Position (CKP) System Variation Learn Procedure before proceeding with this diagnostic table. Refer to CKP System Variation Learn Procedure .
IMPORTANT
An erratic or inconsistent spark is considered a no spark.

DTC P0300

The numbers below refer to the step numbers on the diagnostic table.

  1. 3: This step determines if the fault is present.
  2. 6: This step simulates a CKP sensor signal to the ECM. If the ECM receives the signal, the fuel pump will operate for about 2 seconds.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Attempt to start the engine. Does the engine start and continue to run?Go to Step 3Go to Step 4
3Observe 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 4Go to Intermittent Conditions
4Raise the vehicle. Refer to Lifting and Jacking the Vehicle . Remove the starter. Refer to Starter Motor Replacement (4.2L Engine) or Starter Motor Replacement (5.3L Engine) . Disconnect the crankshaft position (CKP) sensor connector. Turn ON the ignition, with the engine OFF. Measure the voltage from the 12-volt reference circuit of the CKP sensor to a good ground with a DMM. Refer to Troubleshooting with a Digital Multimeter . Does the voltage measure above the specified value?11.8 VGo to Step 5Go to Step 7
5Measure the voltage between the 12-volt reference circuit of the CKP sensor and the low reference circuit of the CKP sensor with a DMM. Does the voltage measure above the specified value?11.8 VGo to Step 6Go to Step 8
6Momentarily connect a test lamp between the CKP sensor signal circuit and the 12-volt reference of the CKP sensor. Does the fuel pump operate when the test lamp is applied to the CKP sensor signal circuit?Go to Step 10Go to Step 9
7Test the 12-volt reference circuit for the following conditions: An open A short to ground High resistance Refer to Circuit Testing and Wiring Repairs . Did you find and correct condition?Go to Step 16Go to Step 12
8Test the low reference circuit for the following conditions: An open A short to voltage High Resistance Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 12
9Test the CKP sensor signal circuit for the following conditions: An open A short to ground A short to voltage High resistance Refer to Circuit Testing and Wiring Repairs Did you find and correct the condition?Go to Step 16Go to Step 12
10Remove the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Visually inspect the CKP sensor for the following conditions: Physical damage Loose or improper installation Wiring routed too closely to the secondary ignition components The following conditions may cause this DTC to set: Excessive air gap between the CKP sensor and the reluctor wheel The CKP sensor coming in contact with the reluctor wheel Foreign material passing between the CKP sensor and the reluctor wheel Did you find and correct the condition?Go to Step 16Go to Step 11
11Visually inspect the CKP sensor reluctor wheel for the following conditions: Loose or improper installation Physical damage Excessive end play or looseness Refer to Crankshaft and Bearings Cleaning and Inspection . Did you find and correct the condition?Go to Step 16Go to Step 14
12Test for poor connections at the CKP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 13
13Test for poor connections at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition?Go to Step 16Go to Step 15
14Replace the CKP sensor. Refer to Crankshaft Position (CKP) Sensor Replacement . Did you complete the replacement?Go to Step 16
15Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 16
16Clear 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 2Go to Step 17
17Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK

DTC P0335

The number below refers to the step number on the diagnostic table.

  1. 4: The test lamp in this step is used to apply a load to the 12-volt reference circuit of the CMP sensor.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Start and idle the engine. Monitor the camshaft position (CMP) sensor active counter parameter with a scan tool. Does the CMP sensor active counter number increment?Go to Intermittent ConditionsGo to Step 3
3Turn OFF the ignition. Disconnect the CMP sensor electrical connector. Test for shorted terminals and poor connections at the CMP sensor wire harness electrical connector and the mating electrical connector on the CMP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 12Go to Step 4
4Turn ON the ignition, with the engine OFF. Connect a jumper wire to the 12-volt reference circuit at the CMP sensor wire harness electrical connector. Connect a test lamp between the jumper wire and a good ground. Connect the positive lead of the DMM to the junction of the jumper wire and test lamp. Connect the negative lead of the DMM to a good engine ground. Measure the voltage from the 12-volt reference circuit to a good ground with a DMM. Refer to Circuit Testing . Is the voltage within the specified range?10-13 VGo to Step 5Go to Step 6
5Remove the test lamp from the jumper wire. Connect another jumper wire to the signal circuit of the CMP sensor wire harness electrical connector. Turn ON the ignition, with the engine OFF. Monitor the CMP active counter parameter with a scan tool. Momentarily connect the two ends of the jumper wires together several times. Does the CMP sensor active counter number increment?Go to Step 10Go to Step 7
6Test the CMP 12-volt reference circuit between the CMP sensor and the engine control module (ECM) for the following conditions: An open High resistance A short to ground Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 9
7Test the CMP low reference circuit between the CMP sensor and the ECM for the following conditions: An open High resistance A short to ground A short to voltage Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 12Go to Step 8
8Test the CMP signal circuit between the CMP sensor and the ECM for the following conditions: An open High resistance A short to ground A short to voltage Did you find and correct the condition?Go to Step 12Go to Step 9
9Test for shorted terminals and poor connections at the ECM wire harness electrical connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 12Go to Step 11
10Replace the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Did you complete the replacement?Go to Step 12
11Replace the ECM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 12
12Clear 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 2Go to Step 13
13Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK

DTC P0340

The numbers below refer to the step numbers on the diagnostic table.

  1. 4: This step inspects for electromagnetic interference (EMI) on the CMP circuits.
  2. 7: Damage to the face of the sensor could indicate material passing between the CMP sensor and the reluctor wheel. This condition could cause this DTC to set. Damage to the reluctor wheel would affect the CMP sensor output signal.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Is DTC P0340 also set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Observe 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 4Go to Intermittent Conditions
4Visually and physically inspect all circuits going to the camshaft position (CMP) sensor for the following: The wire harness routed too close to the secondary ignition wires or components The wire harness routed too close to the aftermarket add-on electrical equipment The wire harness routed too close to the solenoids, relays, and motors If you find the wiring harness incorrectly routed, then position the wire harness correctly. Refer to Harness Routing Views in Wiring Systems. Did you find and correct the condition?Go to Step 9Go to Step 5
5Disconnect the CMP sensor electrical connector. Test for an intermittent and for a poor connection at the CMP sensor wiring harness electrical connector and the mating connector on the CMP 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 10Go to Step 6
6Test 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 10Go to Step 7
7Remove the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Visually inspect the CMP sensor for the following conditions: Physical damage Excessive wear of the sensor Loose or improper installation The sensor coming in contact with the reluctor wheel Foreign material passing between the sensor and the reluctor wheel Did you find and correct the condition?Go to Step 10Go to Step 8
8Visually inspect the CMP sensor reluctor ring or camshaft gear for the following conditions: Physical damage Excessive end play or looseness Loose or improper installation Did you find and correct the condition?Go to Step 10Go to Step 9
9Replace the CMP sensor. Refer to Camshaft Position (CMP) Sensor Replacement . Did you complete the replacement?Go to Step 10
10Clear 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 2Go to Step 11
11Observe 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 InformationSystem OK

DTC P0341

The numbers below refer to the step numbers on the diagnostic table.

  1. 3: This step verifies the integrity of the IC circuit and the ECM output.
  2. 4: This step tests for a short to voltage on the IC circuit.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module (ECM) Connector End Views or Engine Controls Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Observe 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 you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 3Go to Intermittent Conditions
3Turn OFF the engine. Disconnect the respective ignition coil electrical connector. Disconnect the respective fuel injector electrical connector. Start the engine. Measure the frequency at the ignition (IC) circuit with the DMM set to DC Hertz. Refer to Measuring Frequency in Wiring Systems. Is the frequency within the specified range?3-20 HzGo to Step 7Go to Step 4
4Turn ON the ignition, with the engine OFF. Measure the voltage from the IC circuit of the ignition coil to a good ground with a DMM. Is the voltage more than the specified value?1 VGo to Step 13Go to Step 5
5Turn OFF the ignition. Disconnect the engine control module (ECM) connector. Test the IC circuit between the ignition coil connector and the ECM connector for continuity with the DMM. Does the DMM indicate continuity?Go to Step 6Go to Step 14
6Test the respective IC circuit for a short to ground. Refer to Testing for Short to Ground in Wiring Systems. Did you find and correct the condition?Go to Step 17Go to Step 10
7Turn ON the ignition, with the engine OFF. Probe the ignition 1 voltage circuit of the ignition coil with a test lamp that is connected to battery ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate?Go to Step 8Go to Step 11
8Probe the ground circuit of the ignition coil with a test lamp connected to battery voltage. Refer to Troubleshooting with a Test Lamp in Wiring Systems. Does the test lamp illuminate?Go to Step 9Go to Step 12
9Test for an intermittent and for a poor connection at the ignition coil. 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 17Go to Step 15
10Test 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 17Go to Step 16
11Repair the open or high resistance in the ignition 1 voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 17
12Repair the open or high resistance in the ground circuit for the ignition coil. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 17
13Repair the IC circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 17
14Repair the open or high resistance in the IC circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 17
15Replace the ignition coil. Refer to Ignition Coil(s) Replacement . Did you complete the replacement?Go to Step 17
16Replace the ECM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 17
17Clear 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 2Go to Step 18
18Observe 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 InformationSystem OK

DTC P0351-P0358

The numbers below refer to the step numbers on the diagnostic table.

  1. 5: A catalytic converter which has been discolored may be due to an engine running rich, lean, or had a previous misfire. Verifying the fuel trim percentages may be of assistance in determining if such a condition exists.
  2. 6: This steps inspects for conditions than can cause the TWC efficiency to appear degraded.
StepActionValuesYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Review the DTC information on the scan tool. Are any other DTCs set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Start and idle the engine. Allow the engine to reach operating temperature. Increase the engine speed to 2,000 RPM for 2 minutes. Ensure Closed Loop operation is enabled. Return the engine to a stabilized idle. Observe the HO2S 2 voltage parameter on the scan tool for the applicable bank. Is the applicable HO2S 2 voltage parameter transitioning below the first specified value and above the second specified value?350 mV 600 mVGo to Step 5Go to Step 4
4Clear 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 or P0430 set?Go to Step 5Go to Diagnostic Aids
5IMPORTANT: 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: Physical damage Severe discoloration caused by excessive temperatures Internal rattles caused by loose catalyst substrate Restrictions-Refer to Restricted Exhaust in Engine Exhaust. Did you find and correct the condition?Go to Step 10Go to Step 6
6Visually inspect the exhaust system for the following conditions: Leaks-Refer to Exhaust Leakage in Engine Exhaust. Physical damage Loose or missing hardware The heated oxygen sensor (HO2S) 2 for the applicable bank for proper torque Did you find and correct the condition?Go to Step 10Go to Step 7
7Visually inspect the HO2S 2 at the applicable bank for the following conditions: The pigtail and wiring harness contacting the exhaust or any ground Road damage Did you find a condition?Go to Step 8Go to Step 9
8Replace the applicable HO2S 2 sensor. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 2 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 2 . Did you complete the replacement?Go to Step 10
9NOTE: In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter. Replace the TWC. Refer to Catalytic Converter Replacement (4.2L Engine) or Catalytic Converter Replacement (5.3L Engine) in Engine Exhaust.Did you complete the replacement?Go to Step 10
10Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. 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 1 hour and retest the vehicle. 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 2Go to Step 11
11Observe 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 InformationSystem OK
IMPORTANT
Verify that the three-way catalytic converter (TWC) is a high quality part that meets the OEM specifications.
NOTE
In order to avoid damaging the replacement three-way catalytic converter, correct the engine misfire or mechanical fault before replacing the three-way catalytic converter.
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 1 hour and retest the vehicle.

DTC P0420 or P0430

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 is transferred into a vehicle fuel tank while the vehicle is operating. When the vehicle is turned OFF, 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.

  1. 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.
  2. 5: This step verifies that repairs are complete and that no other condition is present.
StepActionYesNo
Schematic Reference: Evaporative Emissions (EVAP) Hose Routing Diagram
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to nitrogen. Connect the nitrogen/smoke hose to the 0.5 mm (0.2 in) test orifice on the bottom-front of the J 41413-200 Evaporative Emission System Tester (EEST). Activate the J 41413-200 with the remote switch. Align the red flag on the flow meter with the floating indicator. De-activate the J 41413-200 with the remote switch. Install the J 41415-40 Fuel Tank Cap Adapter or GE-41415-50 Fuel Tank Cap Adapter to the fuel fill pipe. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . Turn ON the ignition, with the engine OFF. Command the evaporative emission (EVAP) canister vent solenoid valve closed with a scan tool. Introduce nitrogen and fill the EVAP system until the floating stabilizes with the remote switch. Compare the flow meter's stable floating indicator position to the red flag. Is the floating indicator below the red flag?Go to Diagnostic AidsGo to Step 3
3IMPORTANT: 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. Connect the J 41413-200 power supply clips to a known good 12-volt source. Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. Connect the J 41413-200 nitrogen/smoke supply hose to the J 41415-40 or GE-41415-50 . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Turn the nitrogen/smoke valve on the J 41413-200 control panel to SMOKE. Use the remote switch to introduce smoke into the EVAP system. Use the J 41413-VLV EVAP Service Port Vent Fitting to open the EVAP service port. 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 the J 41413-SPT 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 5Go to Step 4
4Disconnect the J 41415-40 or GE-41415-50 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 the J 41413-SPT . 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 5Go to Diagnostic Aids
5IMPORTANT: Larger volume fuel tanks and/or those with lower fuel levels may require several minutes for the floating indicator to stabilize. Turn the nitrogen/smoke valve to nitrogen. Connect the nitrogen/smoke hose to the 0.5 mm (0.2 in) test orifice on the bottom-front of the J 41413-200 . Use the remote switch to activate the J 41413-200 . Align the red flag on the flow meter with the floating indicator. Use the remote switch to de-activate the J 41413-200 . Install the J 41415-40 or GE-41415-50 to the fuel fill pipe. Remove the nitrogen/smoke hose from the test orifice and install the hose onto the J 41415-40 or GE-41415-50 . Turn ON the ignition, with the engine OFF. Command the EVAP canister vent solenoid valve closed with a scan tool. Use the remote switch to introduce nitrogen and fill the EVAP system until the floating stabilizes. Compare the flow meter's stable floating indicator position to the red flag. Is the floating indicator below the red flag?Go to Step 6Go to Step 2
6Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 7
7IMPORTANT: The 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.
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 MIL may remain ON after the repair unless the DTCs are cleared.

DTC P0442

The numbers below refer to the step numbers on the diagnostic table.

  1. 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.
  2. 5: This step verifies that the control module is providing ground to the EVAP canister purge solenoid valve.
  3. 6: This step tests if a ground is constantly being applied to the EVAP canister purge solenoid valve.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Turn 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 3Go to Step 4
3Observe 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 4Go to Testing for Intermittent Conditions and Poor Connections
4Turn 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 5Go to Step 11
5Connect 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 8Go to Step 6
6Command the EVAP canister purge solenoid valve to 50 percent with a scan tool. Does the test lamp illuminate or pulse when the EVAP canister purge solenoid valve is commanded to 50 percent?Go to Step 9Go to Step 7
7Test 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 . Did you find and correct the condition?Go to Step 14Go to Step 10
8Test the control circuit of the EVAP canister purge solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 13
9Inspect 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 . Did you find and correct the condition?Go to Step 14Go to Step 12
10Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 14Go to Step 13
11Repair the open or short to ground in the ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 14
12Replace 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
13Replace the engine control module (ECM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 14
14Clear the DTCs with a scan tool. 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 2Go to Step 15
15Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK

DTC P0443

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 CommandEVAP Canister Purge Solenoid ValveEVAP Canister Vent Solenoid Valve
ONOpenClosed
OFFClosedOpen

DTC P0446

The numbers below refer to the step numbers on the diagnostic table.

  1. 2: Listen for a click when the valve operates. Verify that both the ON and the OFF states are commanded.
  2. 5: This step verifies that the control module is providing ground to the EVAP canister vent solenoid valve.
  3. 6: This step tests if the EVAP canister vent solenoid valve control circuit is grounded.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Engine Control Module (ECM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Turn 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 3Go to Step 4
3Observe 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 4Go to Testing for Intermittent Conditions and Poor Connections
4Turn OFF the ignition. Disconnect the EVAP canister vent solenoid valve. Turn ON the ignition, with the engine OFF. Probe the batter 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 . Does the test lamp illuminate?Go to Step 5Go to Step 11
5Connect a test lamp between the control circuit of the EVAP canister vent solenoid valve and battery positive voltage circuit of the EVAP canister vent solenoid valve at the EVAP canister vent solenoid 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 9Go to Step 6
6Does the test lamp remain illuminated with each command?Go to Step 8Go to Step 7
7Test 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 . Did you find and correct the condition?Go to Step 14Go to Step 10
8Test the control circuit of the EVAP canister vent solenoid valve for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 10
9Inspect 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 . Did you find and correct the condition?Go to Step 14Go to Step 12
10Inspect for poor connections at the harness connector of the control module. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 13
11IMPORTANT: 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 .Did you complete the repair?Go to Step 14
12Replace 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
13Replace the engine control module (ECM). Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 14
14Observe 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 2Go to Step 15
15Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - VehicleSystem OK
IMPORTANT
If the fuse is open, inspect all related circuits for a short to ground.

DTC P0449

See also:
• Scan Tool Data List

More articles — Engine Control System - 5.3L - DTC P0137 to P0449