Home ReviewsRefund
Home/Chevrolet/Chevy Express G2500/Chevrolet Chevy Express G2500 (1996-2012)/Repair manual/Testing & Diagnostics/Engine Control System Diagnosis - 4.3l (DTC p0641 to p1381)
Contents Wiring diagrams Section: Testing & Diagnostics All sections

Engine Control System Diagnosis - 4.3l (DTC p0641 to p1381) Chevrolet Chevy Express G2500

Testing & Diagnostics ~5095 words

Circuit Description

The powertrain control module (PCM) provides 5 volts to the following sensors

  1. The throttle position (TP) sensor
  2. The engine oil pressure (EOP) sensor
  3. The manifold absolute pressure (MAP) sensor

These 5-volt reference circuits are independent of each other outside the PCM, but are bussed together inside the PCM. Therefore a circuit condition on one sensor 5-volt reference circuit may affect the other sensor 5-volt reference circuits. The PCM monitors the voltage on the 5-volt reference circuit. If the PCM detects the voltage is out of tolerance, DTC P0641 sets.

Conditions for Running the DTC

The engine is running.

Conditions for Setting the DTC

  1. The PCM detects a voltage out of tolerance condition on the 5-volt reference circuit.
  2. The above condition is met for more than 10 seconds.

Action Taken When the DTC Sets

  1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
  2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

Conditions for Clearing the MIL/DTC

  1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  4. Clear the MIL and the DTC with a scan tool.

Test Description

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

  1. 9: A short to voltage on the signal circuit of the manifold absolute pressure (MAP) sensor will backfeed through the sensor into the 5-volt reference circuit and set this DTC.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check - Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
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 that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 3Go to Intermittent Conditions
3Turn OFF the ignition. Disconnect the throttle position (TP) sensor. Turn ON the ignition, with the engine OFF. Measure the voltage from the 5-volt reference circuit of the TP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range?4.8-5.2 VGo to Step 4Go to Step 5
4Connect the TP sensor. Disconnect the manifold absolute pressure (MAP) sensor. Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage within the specified range?4.8-5.2 VGo to Intermittent ConditionsGo to Step 11
5Is the voltage measured in Step 3 more than the specified value?5.2 VGo to Step 8Go to Step 6
6Monitor the DMM while disconnecting all other devices connected to the 5-volt reference circuit, one at a time. Refer to Engine Controls Component Views . If the voltage changes when one of the devices are disconnected, replace the component. Refer to appropriate replacement procedure below: The MAP sensor - Refer to Manifold Absolute Pressure (MAP) Sensor Replacement . The EOP sensor - Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical. Did you complete the replacement?Go to Step 13Go to Step 7
7Turn OFF the ignition. Disconnect the powertrain control module (PCM). Test the 5-volt reference circuit for a short to ground or any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
8Test the MAP sensor 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 13Go to Step 9
9Turn OFF the ignition. Disconnect the PCM. Turn ON the ignition, with the engine OFF. Test all 5-volt reference circuits 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 13Go to Step 12
10Replace the MAP sensor. Refer to Manifold Absolute Pressure (MAP) Sensor Replacement . Did you complete the replacement?Go to Step 13
11Replace the EOP sensor. Refer to Engine Oil Pressure Sensor and/or Switch Replacement in Engine Mechanical. Did you complete the replacement?Go to Step 13
12Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . 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) ListSystem OK

DTC P0641

The malfunction indicator lamp (MIL) is located on the instrument panel cluster (IPC). The MIL informs the driver that an emission system fault has occurred and that the engine control system requires service. The control module monitors the MIL control circuit for conditions that are incorrect for the commanded state of the MIL. For example, a failure condition exists if the control module detects low voltage when the MIL is commanded OFF, or high voltage when the MIL is commanded ON. If the control module detects an improper voltage on the MIL control circuit, DTC P0650 will set.

  1. The engine speed is more than 400 RPM.
  2. The ignition voltage is between 6-18 volts.
  1. The control module detects that the commanded state of the MIL driver and the actual state of the control circuit do not match.
  2. The conditions are present for a minimum of 5 seconds.

The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

  1. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  3. Clear the MIL and the DTC with a scan tool.

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

  1. 5: This step tests for a short to ground in the MIL control circuit. With the powertrain control module (PCM) disconnected and the ignition ON, the MIL should be OFF.
  2. 6: This step tests for a short to voltage on the MIL control circuit. With the fuse removed, there should be no voltage on the MIL control circuit.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check - Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Verify whether the instrument cluster is operational. If the instrument panel (I/P) is completely inoperative, refer to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gages and Console. Command the MIL ON and OFF with a scan tool. Does the MIL 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. Does the DTC fail this ignition?Go to Step 4Go to Intermittent Conditions
4Inspect the fuse that supplies battery voltage to the MIL. Is the fuse open?Go to Step 12Go to Step 5
5Turn OFF the ignition. Disconnect the powertrain control module (PCM). Turn ON the ignition. Is the MIL OFF?Go to Step 6Go to Step 13
6Turn OFF the ignition. Remove the fuse that supplies voltage to the MIL. Turn ON the ignition, with the engine OFF. Measure the voltage from the MIL control circuit in the PCM to a good ground. Is the voltage less than the specified value?0.3 VGo to Step 7Go to Step 14
7Turn OFF the ignition. Install the fuse that supplies voltage to the MIL. Turn ON the ignition, with the engine OFF. Connect a 3-amp fused jumper wire between the MIL control circuit of the PCM and a good ground. Is the MIL illuminated?Go to Step 11Go to Step 8
8Turn OFF the ignition. Remove the instrument panel cluster (IPC). Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console. Probe the MIL battery positive voltage circuit of the IPC harness connector with a test lamp that is connected to a good ground. Does the test lamp illuminate?Go to Step 9Go to Step 15
9Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct a condition?Go to Step 18Go to Step 10
10Test for an intermittent and for a poor connection at the IPC. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Repairs. Did you find and correct the condition?Go to Step 18Go to Step 16
11Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Repairs. Did you find and correct the condition?Go to Step 18Go to Step 17
12Repair the short to ground in the battery positive voltage circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 18
13Repair the short to ground in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 18
14Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 18
15Repair the open in the MIL battery positive voltage. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 18
16Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement in Instrument Panel, Gages, and Console. Did you complete the replacement?Go to Step 18
17Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . Did you complete the replacement?Go to Step 18
18Clear 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 19
19Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) ListSystem OK

DTC P0650

The powertrain control module (PCM) provides 5 volts to the fuel tank pressure (FTP) sensor. The PCM monitors the voltage on the 5-volt reference circuit. If the voltage is out of tolerance, DTC P0651 sets.

The engine must be running.

  1. The PCM detects a voltage out of tolerance condition on the 5-volt reference circuit.
  2. The above condition is met for more than 10 seconds.
  1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
  2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
  1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  4. Clear the MIL and the DTC with a scan tool.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you complete the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Observe the Freeze Frame/Failure Records data 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 3Go to Intermittent Conditions
3Turn OFF the ignition. Disconnect the FTP sensor. Turn the ignition ON, with the engine OFF. Measure the voltage from the FTP sensor signal circuit to a good ground with the DMM. Is the voltage less than the specified value?0.3 VGo to Step 4Go to Step 10
4Measure the voltage from the 5-volt reference circuit of the FTP sensor to a good ground with the DMM. Is the voltage within the specified range?4.8-5.2 VGo to Step 5Go to Step 7
5Select this DTC using the Specific DTC mode on the scan tool. Start the engine. Does the scan tool indicate that the DTC failed the last test?Go to Step 12Go to Step 6
6Turn OFF the ignition. Connect the FTP sensor. Start the engine. Does the scan tool indicate that the DTC failed the last test when the FTP is connected?Go to Step 11Go to Intermittent Conditions
7Does the voltage measure more than the specified value?5 VGo to Step 8Go to Step 9
8Turn OFF the ignition. Disconnect the PCM. Test for a short to voltage on the 5-volt reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
9Turn OFF the ignition. Disconnect the PCM. Test the 5-volt reference circuit for a short to ground or any low reference circuit Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the short to voltage in the FTP sensor signal circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 13
11Replace the FTP Sensor. Refer to Fuel Tank Pressure Sensor Replacement . Did you complete the replacement?Go to Step 13
12Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . 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) ListSystem OK

DTC P0651

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits

  1. 5-volt reference circuit
  2. Low reference circuit
  3. MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used in order to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that is intermittently high, DTC P1106 sets.

  1. The engine has been running for a length of time that is determined by start-up coolant temperature. The length of time ranges from 5.5 minutes at less than -30°C (-22°F) to 10 seconds at more than 30°C (86°F).
  2. DTC P0121, P0122, P0123 are not set.
  3. The throttle angle is less than 1 percent when the engine speed is less than 1,200 RPM. OR
  4. The throttle angle is more than 12.5 percent when the engine speed is more than 1,200 RPM.

The PCM detects that the MAP sensor voltage is intermittently more than 4.9 volts.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.

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

  1. 3: This step attempts to pinpoint the location of the intermittent fault.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Start the engine. Monitor the diagnostic trouble code (DTC) Information with the scan tool. Is DTC P0108 or P0641 also set?Go to Diagnostic Trouble Code (DTC) ListGo to Step 3
3Observe the MAP sensor parameter with the scan tool. Attempt to induce the fault that set the DTC by manipulating the following items: The MAP sensor wiring harness The MAP sensor electrical connector The PCM connector Refer to Inducing Intermittent Fault Conditions in Wiring Systems and Intermittent Conditions .Is the MAP sensor voltage affected during any part of the test?Go to Step 4Go to Step 8
4Test the low reference circuit between the PCM and the MAP sensor for an intermittent open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 5
5IMPORTANT: Disconnecting the PCM may eliminate the short during testing. Test the MAP sensor signal circuit between the PCM and the MAP sensor for an intermittent short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?Go to Step 8Go to Step 6
6Test for an intermittent and for a poor connection at the MAP 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 8Go to Step 7
7Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you complete the action?Go to Step 8
8Clear 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) ListSystem OK
IMPORTANT
Disconnecting the PCM may eliminate the short during testing.

DTC P1106

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits

  1. 5-volt reference circuit
  2. Low reference circuit
  3. MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used in order to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that is intermittently low, DTC P1107 sets.

  1. The ignition is ON.
  2. DTC P0121, P0122, P0123 are not set.
  3. The throttle angle is more than 0 percent when the engine speed is less than 800 RPM. OR
  4. The throttle angle is more than 12.5 percent when the engine speed is more than 800 RPM.

The PCM detects that the MAP sensor voltage is intermittently less than 0.10 volt.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.

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

  1. 3: This step attempts to pinpoint the location of the intermittent fault.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Start the engine. Monitor the diagnostic trouble code (DTC) Information with the scan tool. Is DTC P0107 or P0641 also set?Go to Diagnostic Trouble Code (DTC) ListGo to Step 3
3Turn OFF the ignition. Turn ON the ignition, with the engine OFF. Observe the MAP sensor parameter with the scan tool. Attempt to induce the fault that set the DTC by manipulating the following items: The MAP sensor wiring harness The MAP sensor electrical connector The PCM connector Refer to Inducing Intermittent Fault Conditions in Wiring Systems and Intermittent Conditions .Is the MAP sensor voltage affected during any part of the test?Go to Step 4Go to Step 8
4Test the 5-volt reference circuit between the PCM and the MAP sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 5
5Test the MAP sensor signal circuit between the PCM and the MAP sensor for an intermittent short to ground or open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 6
6Test for an intermittent and for a poor connection at the MAP 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 8Go to Step 7
7Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you complete the action?Go to Step 8
8Clear 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) ListSystem OK

DTC P1107

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an intermittent high IAT signal voltage, indicating a low temperature, DTC P1111 sets.

  1. DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0125, P0128, P0502, P0503, P1114, and P1115 are not set.
  2. The engine run time is more than 120 seconds.
  3. The engine coolant is more than 60°C (140°F).
  4. The vehicle speed is less than 11 km/h (7 mph).
  5. The mass air flow (MAF) is less than 15 g/s.

The PCM detects that the IAT is less than -38°C (-36°F) intermittently for more than 4 minutes.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Observe the DTC Information with a scan tool. Is DTC P0113 set?Go to DTC P0113Go to Step 3
3Test for an intermittent and for a poor connection at the intake air temperature (IAT) 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 8Go to Step 4
4Test the IAT signal circuit between the IAT sensor and the powertrain control module (PCM) for an intermittent open. Refer to Inducing Intermittent Fault Conditions and Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 5
5Test the IAT signal circuit between the IAT sensor and the PCM for an intermittent short to voltage. Refer to Inducing Intermittent Fault Conditions and Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 6
6Test the low reference circuit for an intermittent open. Refer to Inducing Intermittent Fault Conditions and Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 7
7Test for an intermittent and for a poor connection at the PCM. 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 8Go to Intermittent Conditions
8Clear 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) ListSystem OK

DTC P1111

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an intermittent low IAT signal voltage, indicating a high temperature, DTC P1112 sets.

  1. DTCs P0500, P0502, and P0503 are not set.
  2. The engine run time is more than 45 seconds.
  3. The vehicle speed is more than 40 km/h (25 mph).

The PCM detects that the IAT is more than 128°C (262°F) intermittently for more than 4 minutes.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.
StepActionValue(s)YesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Observe the DTC information with a scan tool. Is DTC P0112 set?Go to DTC P0112Go to Step 3
3Test for an intermittent and for a poor connection at the intake air temperature (IAT) 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 5Go to Step 4
4Test the IAT signal circuit between the IAT sensor and the powertrain control module (PCM) for an intermittent short to ground. Refer to Inducing Intermittent Fault Conditions and Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 5Go to Intermittent Conditions
5Clear 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 6
6Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) ListSystem OK

DTC P1112

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively low ECT signal voltage, which is a high temperature indication, DTC P1114 sets.

Engine run time is more than 10 seconds.

The PCM detects that the ECT sensor parameter is more 138°C (280°F) intermittently for more than 4 minutes.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Observe the DTC information with a scan tool. Is DTC P0117 set?Go to DTC P0117Go to Step 3
3Observe the engine coolant temperature (ECT) sensor parameter with a scan tool while moving the ECT sensor connector and the powertrain control module (PCM) connector. Refer to Inducing Intermittent Fault Conditions in Wiring Systems. Does the scan tool indicate an abrupt change in value?Go to Step 5Go to Step 4
4Observe the ECT parameter with a scan tool while moving the wiring harness at the ECT sensor and the PCM. Refer to Inducing Intermittent Fault Conditions in Wiring Systems. Does the scan tool indicate an abrupt change in value?Go to Step 6Go to Step 7
5Repair the connector or the terminal as necessary. Refer to Connector Repairs in Wiring Systems. Did you complete the repair?Go to Step 8
6Repair the wiring or the wiring harness as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 8
7Clear 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 8
8Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) ListSystem OK

DTC P1114

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively high signal voltage, which is a low temperature indication, DTC P1115 sets.

The engine run time is more than 60 seconds.

The PCM detects that the ECT sensor parameter is less than -38°C (-36°F) intermittently for more than 4 minutes.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Observe the DTC information with a scan tool. Is DTC P0118 set?Go to DTC P0118Go to Step 3
3Observe the engine coolant temperature (ECT) sensor parameter with a scan tool while moving the ECT sensor connector and the powertrain control module (PCM) connector. Refer to Inducing Intermittent Fault Conditions in Wiring Systems. Does the scan tool indicate an abrupt change in value?Go to Step 5Go to Step 4
4Observe the ECT parameter with a scan tool while moving the wiring harness at the ECT sensor and the PCM. Refer to Inducing Intermittent Fault Conditions in Wiring Systems. Does the scan tool indicate an abrupt change in value?Go to Step 6Go to Step 7
5Repair the connector or the terminal as necessary. Refer to Connector Repairs in Wiring Systems. Did you complete the repair?Go to Step 8
6Repair the wiring harness or the wiring as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 8
7Clear 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 8
8Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) ListSystem OK

DTC P1115

The throttle position (TP) sensor is used by the powertrain control module (PCM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with three circuits

  1. A 5-volt reference circuit
  2. A low reference circuit
  3. A TP sensor signal circuit

The PCM provides the TP sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Rotation of the TP sensor rotor from the closed throttle position to the wide open throttle (WOT) position provides the PCM with a signal voltage from below 1.0 volt to greater than 4.0 volts through the TP sensor signal circuit. If the PCM detects an intermittent excessively high signal voltage, DTC P1121 sets.

  1. The ignition is ON.
  2. DTC P0641, P0651 are not set.

The PCM detects that the TP sensor voltage is intermittently more than 4.9 volts.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.

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

  1. 7: This test will determine an intermittent faulty TP sensor utilizing the MIN MAX, 100 millisecond capture mode on the DMM.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Disconnect the throttle position (TP) sensor electrical connector. Turn ON the ignition, with the engine OFF. Measure the voltage from the 5-volt reference circuit of the TP sensor to a good ground with a DMM. Lightly touch and move the related engine wiring harnesses and connectors for all 5-volt reference circuits while observing voltage. Any change in voltage indicates the area where a short to voltage may be found. Refer to Testing for Electrical Intermittents and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 9Go to Step 3
3Measure the voltage from the signal circuit of the TP sensor to a good ground with a DMM. Lightly touch and move the related engine wiring harnesses and connectors while observing voltage. Any change in voltage indicates the area where a short to voltage may be found. Refer to Testing for Electrical Intermittents and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 9Go to Step 4
4Measure the resistance from the low reference circuit of the TP sensor to a good ground with a DMM. Lightly touch and move the related engine wiring harnesses and connectors while observing resistance. Any change in resistance indicates the area where an open or high resistance may be found. Refer to Testing for Electrical Intermittents , Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 9Go to Step 5
5Test for intermittent and for poor connections at the TP sensor harness connector. 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 9Go to Step 6
6Test for intermittent and for poor connections at the powertrain control module (PCM) harness connector. 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 9Go to Step 7
7Turn OFF the ignition. Measure the resistance between the TP sensor signal terminal and the low reference terminal at the TP sensor using the MIN MAX function on the DMM. Slowly press the accelerator pedal to the wide open throttle (WOT) position, then release the pedal back to the closed throttle position several times. Did you observe a MAX value of infinite ohms or a MIN value of 0 ohms.Go to Step 8Go to Intermittent Conditions
8Replace the TP sensor. Refer to Throttle Position (TP) Sensor Replacement . Did you complete the replacement?Go to Step 9
9Clear 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 10
10Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) ListSystem OK

DTC P1121

The throttle position (TP) sensor is used by the powertrain control module (PCM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with three circuits

  1. A 5-volt reference circuit
  2. A low reference circuit
  3. A TP sensor signal circuit

The PCM provides the TP sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Rotation of the TP sensor rotor from the closed throttle position to the wide open throttle (WOT) position provides the PCM with a signal voltage from below 1.0 volt to greater than 4.0 volts through the TP sensor signal circuit. If the PCM detects an intermittent excessively low signal voltage, DTC P1122 sets.

  1. The ignition is ON.
  2. DTC P0641, P0651 are not set.

The PCM detects that the TP sensor voltage is intermittently less than 0.15 volts.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.

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

  1. 6: This test will determine an intermittent faulty TP sensor utilizing the MIN MAX, 100 millisecond capture mode on the DMM.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Disconnect the throttle position (TP) sensor. Measure the voltage from the 5-volt reference circuit of the TP sensor to a good ground, with a DMM. Turn ON the ignition, with the engine OFF. Lightly touch and move the related engine wiring harnesses and connectors for all 5-volt reference circuits while observing the DMM. Any change in voltage indicates the area where an open or a short to ground in the 5-volt reference circuit may be found. Refer to Testing for Electrical Intermittents , Testing for Intermittent Conditions and Poor Connections and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 3
3Connect the TP sensor. Install a scan tool and observe the TP sensor voltage parameter. Lightly touch and move the related engine wiring harnesses and connectors for the TP sensor signal circuit while observing voltage. Any change in voltage indicates the area where an open or a short to ground in the TP sensor signal circuit may be found. Refer to Testing for Electrical Intermittents and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 8Go to Step 4
4Test for intermittent and for poor connections at the TP sensor harness connector. 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 8Go to Step 5
5Test for intermittent and for poor connections at the harness connector of the powertrain control module (PCM). 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 8Go to Step 6
6Turn OFF the ignition. Measure the resistance between the TP sensor signal terminal and the 5-volt reference terminal at the TP sensor using the MIN MAX function on the DMM. Slowly press the accelerator pedal to the wide open throttle (WOT) position, then release the pedal back to the closed throttle position several times. Did you observe a MAX value of infinite ohms or a MIN value of 0 ohms?Go to Step 7Go to Intermittent Conditions
7Replace the TP sensor. Refer to Throttle Position (TP) Sensor Replacement . Did you complete the replacement?Go to Step 8
8Clear 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) ListSystem OK

DTC P1122

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and closed loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. This diagnostic will only run once per ignition cycle. The PCM monitors the number of rich-to-lean and lean-to-rich transitions. If the PCM detects that the number of transitions were less than a specified value, DTC P1133 sets for HO2S bank 1 sensor 1, or DTC P1153 sets for HO2S bank 2 sensor 1.

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0200, P0300, P0442, P0446, P0452, P0453, P0455, P0496 are not set.
  2. The ECT Sensor parameter is more than 60°C (140°F).
  3. The EVAP Purge Solenoid Command parameter is more than 1 percent.
  4. The MAF Sensor parameter is between 20-55 g/s.
  5. The Engine Speed parameter is between 1,200-3,000 RPM.
  6. The TP Sensor parameter is more than 5 percent.
  7. The Loop Status parameter is closed.
  8. The Ignition 1 Signal parameter is between 10-18 volts.
  9. The Fuel Tank Level Remaining parameter is more than 10 percent.
  10. The Engine Run Time parameter is more than 160 seconds.
  11. The above conditions are met for 100 seconds.

The PCM detects that the affected HO2S lean-to-rich or rich-to-lean transitions are less than a calibrated value.

  1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
  2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
  1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  4. Clear the MIL and the DTC with a scan tool.

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

  1. 2: 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 Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Start 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 affected heated oxygen sensor (HO2S) voltage parameter with a scan tool. Is the HO2S voltage parameter varying above and below the specified range?250-625 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
5Connect 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 8Go to Step 7
6Test the HO2S high signal circuit for a short to the HO2S low signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 14Go to Step 11
7Test the HO2S high 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 14Go to Step 11
8Remove 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 10Go to Step 9
9Test the HO2S low 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 14Go to Step 11
10Test for shorted terminals and for poor connections at the HO2S. 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
11Test for shorted terminals and for poor connections at the powertrain control module (PCM). 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
12NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. IMPORTANT: The HO2S may be damaged due to contamination. Prior to replacing the HO2S inspect for the following sources of contamination: A silicon contaminated HO2S Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool) . Engine oil consumption-Refer to Oil Consumption Diagnosis in Engine Mechanical. Engine coolant consumption-Refer to Loss of Coolant in Engine Cooling. Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 1 .Did you complete the replacement?Go to Step 14
13Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . 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) ListSystem OK
NOTE
Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices.
IMPORTANT
The HO2S may be damaged due to contamination. Prior to replacing the HO2S inspect for the following sources of contamination

DTC P1133 or P1153

Heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and closed loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. This diagnostic will only run once per ignition cycle. The PCM monitors the rich-to-lean and lean-to-rich transition time. A transition is defined as, the HO2S voltage changes from above 625 mV to below 250 mV or from below 250 mV to above 625 mV. If the PCM detects that the difference between the rich-to-lean average transition time and lean-to-rich average transition time is more than a specified value, DTC P1134 sets for HO2S bank 1 sensor 1, or DTC P1154 sets for HO2S bank 2 sensor 1.

  1. DTCs P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0200, P0220, P0300, P0442, P0446, P0452, P0453, P0455, P0496, are not set.
  2. The ECT Sensor parameter is more than 60°C (140°F).
  3. The EVAP Purge Solenoid Command parameter is more than 1 percent.
  4. The MAF Sensor parameter is between 20-55 g/s.
  5. The Engine Speed parameter is between 1,200-3,000 RPM.
  6. The TP sensor parameter is more than 5 percent.
  7. The Loop Status parameter is closed.
  8. The Ignition 1 Signal parameter is between 10-18 volts.
  9. The Fuel Tank Level Remaining parameter is more than 10 percent.
  10. The Engine Run Time parameter is more than 160 seconds.
  11. The above conditions are met for 100 seconds.

The PCM detects that the difference between the HO2S rich-to-lean average transition time and the lean-to-rich average transition time is more than a calibrated value.

  1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
  2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.
  1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
  2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
  3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
  4. Clear the MIL and the DTC with a scan tool.

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

  1. 2: 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 Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check-Engine Controls?Go to Step 2Go to Diagnostic System Check - Engine Controls
2Start 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 affected heated oxygen sensor (HO2S) voltage parameter with a scan tool. Is the HO2S voltage parameter varying above and below the specified range?250-625 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. Connect 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. 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
5Test the HO2S high 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 12Go to Step 9
6Remove 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 8Go to Step 7
7Test the HO2S low 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 12Go to Step 9
8Test for shorted terminals and for poor connections at the HO2S. 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 12Go to Step 10
9Test for shorted terminals and for poor connections at the powertrain control module (PCM). 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 12Go to Step 11
10NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices. IMPORTANT: The HO2S may be damaged due to contamination. Prior to replacing the HO2S inspect for the following sources of contamination: A silicon contaminated HO2S Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool) . Engine oil consumption-Refer to Oil Consumption Diagnosis in Engine Mechanical. Engine coolant consumption-Refer to Loss of Coolant in Engine Cooling. Replace the affected HO2S. Refer to Heated Oxygen Sensor (HO2S) Replacement Bank 1 Sensor 1 or Heated Oxygen Sensor (HO2S) Replacement Bank 2 Sensor 1 .Did you complete the replacement?Go to Step 12
11Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement . 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) ListSystem OK
NOTE
Refer to Silicon Contamination of Heated Oxygen Sensors Notice in Cautions and Notices.
IMPORTANT
The HO2S may be damaged due to contamination. Prior to replacing the HO2S inspect for the following sources of contamination

DTC P1134 or P1154

System Description

The powertrain control module (PCM) detects engine misfire events by monitoring variations in the crankshaft rotation speed. Wheel speed changes caused by rough road conditions can cause changes in crankshaft rotation speed. By monitoring the wheel speed sensors, the anti-lock brake system (ABS) can determine if the vehicle is operating on a rough road. If the ABS is detecting a rough road condition severe enough to effect misfire detection, a rough road signal is sent to the PCM on the serial data circuit. If DTC P0300 is set and the rough road information is not available due to an ABS malfunction, DTC P1380 will set.

  1. DTCs P0101, P0102, P0103, P0121, P0122, P0123, P0335, P0336, P0742 are not set.
  2. The vehicle speed is more than 16 km/h (10 mph).
  3. The engine load is less than 60 percent.
  4. The engine misfire is detected-DTC P0300 set.
  5. The engine speed is less than 3,200 RPM.

An ABS malfunction exists preventing the PCM from receiving rough road detection data.

  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.
StepActionYesNo
1Did you perform the Diagnostic System Check-Engine Controls?Go to Diagnostic System Check - ABS (W/O JL4) in Antilock Brake SystemGo to Diagnostic System Check - Engine Controls

DTC P1380

The powertrain control module (PCM) detects engine misfire events by monitoring variations in the crankshaft rotation speed. Wheel speed changes caused by rough road conditions can cause changes in crankshaft rotation speed. By monitoring the wheel speed sensors, the anti-lock brake system (ABS) can determine if the vehicle is operating on a rough road. If the ABS is detecting a rough road condition severe enough to effect misfire detection, a rough road signal is sent to the PCM on the serial data circuit. If DTC P0300 is set and the rough road information is not available due to an ABS malfunction, DTC P1381 will set.

  1. The vehicle speed is more than 16 km/h (10 mph).
  2. The engine speed is less than 3,200 RPM.
  3. The engine load is less than 60 percent.
  4. Engine misfire is detected-DTC P0300 set.
  1. A serial data malfunction exists preventing the PCM from receiving rough road detection data.
  2. The above conditions met for 20 seconds.
  1. The control module stores the DTC information into memory when the diagnostic runs and fails.
  2. The malfunction indicator lamp (MIL) will not illuminate.
  3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
  4. The driver information center, if equipped, may display a message.
  1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
  2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
  3. Clear the DTC with a scan tool.

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

  1. 1: This step will diagnose a malfunction in the serial data circuits.
StepActionYesNo
1Did you perform the Diagnostic System Check-Engine Controls?Go to Diagnostic System Check - ABS (W/O JL4) in Antilock Brake SystemGo to Diagnostic System Check - Engine Controls

DTC P1381

See also:
• Engine Controls Schematics
• Engine Controls Connector End Views
• Powertrain Control Module (PCM) Connector End Views
• Diagnostic System Check - Engine Controls
• Intermittent Conditions
• Circuit Testing
• Engine Oil Pressure Sensor and/or Switch Replacement
• Wiring Repairs
• Powertrain Control Module (PCM) Replacement
• Diagnostic Trouble Code (DTC) List
• Diagnostic System Check - Instrument Cluster
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Inducing Intermittent Fault Conditions
• DTC P0113
• Testing for Electrical Intermittents
• Scan Tool Data List
• Silicon Contamination of Heated Oxygen Sensors Notice
• Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)
• Oil Consumption Diagnosis
• Loss of Coolant
• Diagnostic System Check - ABS (W/O JL4)

More articles — Engine Performance