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Engine Controls - 8.1L - Diagnostics (Dtcs P0506-U0107): Overview Chevrolet Silverado 1500

Testing & Diagnostics ~1789 words

Test Description

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

  1. 2: This test determines whether the engine can achieve the commanded RPM. If the engine does not reach the commanded RPM, the test determines whether the RPM is too high or too low.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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 the engine. Command the engine speed up to 1,500 RPM, down to 500 RPM, and up to 1,500 RPM with a scan tool. Exit the engine speed control function. Does the engine speed correspond, within 100 RPM, with each command?Go to Diagnostic AidsGo to Step 3
3Is the engine RPM 100 RPM more than the desired RPM?Go to Step 4Go to Step 5
4Inspect for the following conditions: Vacuum leaks Excessive deposits in the throttle body A faulty positive crankcase ventilation system Did you complete the repair?Go to Step 6
5Inspect for energy draining load on the engine, such as ones caused by transmission conditions. Did you find and correct the condition?Go to Step 6
6Clear 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 7
7Observe 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 P0506 or P0507

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

  1. 2: A DTC P0602 indicates the PCM is not programmed.
StepActionYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Is DTC P0602 set?Go to Step 3Go to Step 5
3Program the powertrain control module (PCM). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Does DTC P0602 reset?Go to Step 4Go to Step 7
4Ensure that all tool connections are secure. Ensure that the programming equipment is operating correctly. Ensure that the correct software/calibration package is used. Attempt to program the PCM. Refer to Service Programming System (SPS) in Programming and Setup. Does DTC P0602 reset?Go to Step 6Go to Step 7
5Test all voltage and ground inputs to the PCM for an open circuit or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 7Go to Step 6
6Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 7
7Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. 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) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610

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

  1. 9: A short to voltage on the signal circuit of the 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 - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
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. Does the DTC fail this ignition?Go to Step 3Go to Testing for Intermittent Conditions and Poor Connections
3Turn OFF the ignition. Disconnect the engine oil pressure (EOP) sensor. Turn ON the ignition, with the engine OFF. Measure the voltage from the 5-volt reference circuit of the EOP sensor to a good ground with a DMM. Refer to Circuit Testing . Is the voltage within the specified range?4.8-5.2 VGo to Step 4Go to Step 5
4Connect the EOP 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 . Is the voltage within the specified range?4.8-5.2 VGo to Testing for Intermittent Conditions and Poor ConnectionsGo 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 the MAP sensor. Does the voltage return to within the specified range when the MAP sensor is disconnected?4.8-5.2 VGo to Step 10Go 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 . Did you find and correct the condition?Go to Step 13Go to Step 12
8Test all 5-volt reference circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 13Go to Step 9
9Test the MAP sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . 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 . Did you complete the replacement?Go to Step 13
12Replace the PCM. 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

DTC P0641

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: Instrument Cluster Schematics or Engine Controls Schematics Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views or Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Command the malfunction indicator lamp (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 Testing for Intermittent Conditions and Poor Connections
4Is the MIL always ON?Go to Step 5Go to Step 6
5Turn OFF the ignition. Disconnect the powertrain control module (PCM). Turn ON the ignition. Is the MIL OFF?Go to Step 11Go to Step 13
6Turn OFF the ignition. Disconnect the PCM. 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 harness connector to a good ground. Is the voltage less than the specified value?1 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 harness connector 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). Turn ON the ignition, with the engine OFF. Probe all ignition and battery positive voltage circuits of the IPC harness connector with a test lamp that is connected to a good ground. Does the test lamp illuminate for all circuits?Go to Step 9Go to Step 12
9Test the MIL control circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct a condition?Go to Step 17Go 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 . Did you find and correct the condition?Go to Step 17Go to Step 15
11Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 17Go to Step 16
12Repair the open in the ignition voltage or battery positive voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 17
13Repair the short to ground in the MIL control circuit. Refer to Wiring Repairs . Did you find and correct the condition?Go to Step 17
14Repair the short to voltage in the MIL control circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 17
15Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement . Did you complete the replacement?Go to Step 17
16Replace the PCM. Refer to Control Module References 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 - VehicleSystem OK

DTC P0650

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: Powertrain Control Module (PCM) 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 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 Testing for Intermittent Conditions and Poor Connections
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 the following procedures: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs 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 the following procedures: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs 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 the following procedures: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs 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 the following procedures: 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 14Go to Step 12
11Test for shorted terminals and for poor connections at the powertrain control module (PCM). Refer to the following procedures: 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 14Go to Step 13
12NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice . 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 . Engine coolant consumption-Refer to Loss of Coolant . 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 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
NOTE
Refer to Silicon Contamination of Heated Oxygen Sensors Notice .
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 . Engine coolant consumption-Refer to Loss of Coolant .

DTC P1133 or P1153

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: Powertrain Control Module (PCM) 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 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 Testing for Intermittent Conditions and Poor Connections
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 the following procedures: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs 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 the following procedures: Circuit Testing Wiring Repairs Heated Oxygen Sensor (HO2S) Wiring Repairs 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 the following procedures: 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 12Go to Step 10
9Test for shorted terminals and for poor connections at the powertrain control module (PCM). Refer to the following procedures: 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 12Go to Step 11
10NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice . 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 . Engine coolant consumption-Refer to Loss of Coolant . 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 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
NOTE
Refer to Silicon Contamination of Heated Oxygen Sensors Notice .
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 . Engine coolant consumption-Refer to Loss of Coolant .

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 speed. By monitoring the wheel speed sensors, the antilock 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 with the malfunction indicator lamp (MIL) illuminated, and the rough road information is not available due to an ABS malfunction, DTC P1380 will set.

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 speed. By monitoring the wheel speed sensors, the antilock 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 with the malfunction indicator lamp (MIL) illuminated, and there is no communication with the brake control module, DTC P1381 will set.

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

  1. 7: If the TP indicated angle does not follow the movement of the throttle blade and no TP sensor DTCs are set, there is a mechanical condition with the throttle shaft or the TP sensor.
  2. 18: Locating and repairing an individual condition may correct more than one DTC.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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
2Is DTC U0107 set?Go to DTC U0107Go to Step 3
3Is DTC P2135 set?Go to DTC P2135Go to Step 4
4IMPORTANT: Low system voltage may cause this DTC to set. Clear DTCs if low system voltage has been experienced. Turn OFF the ignition for 15 seconds. Turn ON the ignition, with the engine OFF. Observe the Throttle Position (TP) Sensor 1 and TP Sensor 2 Angle parameters with a scan tool. Slowly depress the accelerator pedal to wide open throttle (WOT) and slowly return it to the released position. Does the scan tool indicate both Angle parameters increasing as the pedal is depressed to WOT and decreasing as the pedal is released?Go to Diagnostic AidsGo to Step 5
5Turn OFF the ignition. Disconnect the throttle actuator motor harness connector. Remove the air inlet duct from the throttle body. Inspect the throttle body and throttle plate for the following conditions which may cause the throttle plate to bind: Debris-If debris is found, clean the throttle body and repair the source of contamination. Damage or evidence of tampering-If the throttle body and/or throttle plate is damaged, replace the throttle body. Refer to Throttle Body Assembly Replacement . Did you find and correct the condition?Go to Step 17Go to Step 6
6With your hand, slowly open the throttle plate to WOT and back to the closed position several times. Does the throttle plate move smoothly without binding in both directions?Go to Step 7Go to Step 14
7Turn OFF the ignition. Disconnect the throttle body harness connector. Connect the jumper wires between the TP sensor terminals of the throttle body harness connector and the corresponding TP sensor terminals of the throttle body. Turn ON the ignition, with the engine OFF. Open the throttle blade to WOT, then to the closed position by hand. Observe the TP Sensor 1 and TP Sensor 2 Angle parameters with a scan tool. Does the scan tool indicate both Angle parameters increasing as the throttle plate is moved to WOT, and decreasing as the plate is moved to the closed position?Go to Step 8Go to Step 15
8Turn OFF the ignition. Disconnect the throttle actuator control (TAC) module harness connector containing the throttle actuator control motor circuits. Turn ON the ignition, with the engine OFF. Test the TAC motor circuits for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 17Go to Step 9
9Test each TAC motor circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 17Go to Step 10
10Test each TAC motor circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 17Go to Step 11
11Disconnect the other TAC module harness connector. Test for a short between each TAC motor circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 17Go to Step 12
12Turn OFF the ignition. Connect the TAC module. Connect a test lamp between the two TAC motor circuits at the TAC motor harness connector. Turn ON the ignition, with the engine OFF, and observe the test lamp. Did the test lamp illuminate briefly when the ignition was turned ON?Go to Step 13Go to Step 15
13Inspect for poor connections at the TAC motor harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 17Go to Step 14
14Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 15
15Inspect for poor connections at the TAC module harness connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 17Go to Step 16
16Replace the TAC module. Refer to Control Module References 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 - VehicleSystem OK
IMPORTANT
Low system voltage may cause this DTC to set. Clear DTCs if low system voltage has been experienced.

DTC P1516

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

  1. 4: If the TP indicated angle does not follow the movement of the throttle blade, and no TP sensor DTCs are set, there is a mechanical condition with the throttle shaft or the TP sensor.
  2. 15: Locating and repairing an individual condition may correct more than one DTC.
StepActionYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Is DTC U0107 also set?Go to DTC U0107Go to Step 3
3IMPORTANT: The next test must be started within 15 seconds after the ignition is turned ON. Turn OFF the ignition for 15 seconds. Turn ON the ignition, with the engine OFF. Observe the Throttle Position (TP) Sensor 1 and TP Sensor 2 Angle parameters with a scan tool. Slowly depress the accelerator pedal to wide open throttle (WOT) and slowly return the pedal to the released position. Does the scan tool indicate both Angle parameters increasing as the pedal is depressed to WOT and decreasing as the pedal is moved to the released position?Go to Diagnostic AidsGo to Step 4
4Turn OFF the ignition. Remove the air inlet duct from the throttle body. Disconnect the throttle body harness connector. Connect the jumper wires between the TP sensor terminals of the throttle body harness connector and the corresponding TP sensor terminals of the throttle body. Turn ON the ignition with the engine OFF. Open the throttle blade to WOT and then to the closed position by hand. Observe the TP Sensor 1 and TP Sensor 2 Angle parameters with a scan tool. Does the scan tool indicate both Angle parameters increasing as the throttle plate is moved to WOT, and decreasing as the throttle plate is moved to the closed position?Go to Step 5Go to Step 12
5Turn OFF the ignition. Disconnect the throttle actuator control (TAC) module harness connector containing the TAC motor circuits. Turn ON the ignition, with the engine OFF. Test the TAC motor circuits for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 6
6Test each TAC motor circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 7
7Test each TAC motor circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 8
8Disconnect the other TAC module harness connector. Remove all jumper wires. Test for a short between each TAC motor circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 14Go to Step 9
9Turn OFF the ignition. Connect the TAC module. Connect a test lamp between the two TAC motor circuits at the TAC motor harness connector. Turn ON the ignition, with the engine OFF, and observe the test lamp. Did the test lamp illuminate briefly when the ignition was turned ON?Go to Step 10Go to Step 12
10Inspect for poor connections at the TAC motor harness connector. 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 11
11Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 14
12Inspect for poor connections at the TAC module harness connectors. 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
13Replace the TAC module. 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 next test must be started within 15 seconds after the ignition is turned ON.

DTC P2101

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

  1. 4: Locating and repairing an individual condition may correct more than 1 DTC.
StepActionYesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Replace the throttle actuator control (TAC) module. Refer to Throttle Actuator Control (TAC) Module Replacement . Did you complete the replacement?Go to Step 3
3Clear 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 4
4Observe 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 P2108

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

  1. 12: This test isolates whether the short is to another TAC System circuit in the harness or within the TAC module.
  2. 26: When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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
2IMPORTANT: If DTC P0120 or U0107 is also set, refer to the appropriate DTC for further diagnosis. Turn ON the ignition with the engine OFF, and with your foot OFF the accelerator pedal. Observe the accelerator pedal position (APP) sensor 1 voltage with a scan tool. Does the scan tool indicate the APP sensor 1 voltage is within the specified values?0.24-2.24 VGo to Step 3Go to Step 6
3Depress the accelerator pedal to the wide open throttle (WOT) position. Does the scan tool indicate APP sensor 1 voltage within the specified values?0.24-4.49 VGo to Step 4Go to Step 6
4Turn OFF the ignition for 30 seconds. Turn ON the ignition, with the engine OFF. Select the diagnostic trouble code (DTC) option using the scan tool. Lightly touch and move the related engine wiring harnesses and connectors while monitoring the DTC information. Did this DTC fail this ignition during the above test?Go to Step 24Go to Step 5
5Continue to observe the DTC Information. Depress the accelerator pedal to WOT, then return the pedal to the rest position. Did this DTC fail this ignition during the above test?Go to Step 19Go to Diagnostic Aids
6Disconnect the APP sensor harness connector. Does the scan tool indicate the APP sensor 1 voltage is at the specified value?0 VGo to Step 7Go to Step 11
7Connect a test lamp between the APP sensor 1 signal circuit and B+. Does the scan tool indicate the APP sensor 1 voltage is at the specified value?5 VGo to Step 8Go to Step 13
8Test the APP sensor 1, 5-volt reference circuit for voltage with a DMM. Does the DMM indicate voltage within the specified values?4.54-5.21 VGo to Step 10Go to Step 9
9Turn OFF the ignition. Disconnect the throttle actuator motor harness connector. Remove the air inlet duct from the throttle body assembly. Turn ON the ignition, with the engine OFF. Rotate the throttle blade by hand to WOT and hold. Test the APP sensor 1, 5-volt reference circuit for voltage with a DMM. Does the DMM indicate voltage within the specified values?4.54-5.21 VGo to Step 21Go to Step 16
10Connect a fused jumper between the APP sensor 1 low-reference circuit and the APP sensor 1, 5-volt reference circuit. Observe the Throttle Position (TP) Sensor 1 Voltage parameter with a scan tool. Does the scan tool indicate TP sensor 1 voltage at the specified value?0 VGo to Step 19Go to Step 17
11Turn OFF the ignition. Disconnect the throttle actuator control (TAC) module harness connector containing the APP sensor circuits. Turn ON the ignition, with the engine OFF. Test the APP sensor 1 signal circuit for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 12
12Turn OFF the ignition. Disconnect the other TAC module harness connector. Test for a short between the APP sensor 1 signal circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 22
13Turn OFF the ignition. Disconnect the TAC module harness connector containing the APP sensor circuits. Test the APP sensor 1 signal circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs Did you find and correct the condition?Go to Step 25Go to Step 14
14Test the APP sensor 1 signal circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 15
15Turn OFF the ignition. Disconnect the other TAC module harness connector. Test for a short between the APP sensor 1 signal circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 22
16Turn OFF the ignition. Disconnect the TAC module connector containing the APP sensor circuits. Test the APP sensor 1, 5-volt reference circuit for the following conditions with a DMM: An open A short to ground High resistance Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 22
17Disconnect the TAC module connector containing the APP sensor circuits. Test the APP sensor 1 low-reference circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 18
18Test the TAC module ground circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 22
19Inspect for poor connections at the harness connector of the APP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 25Go to Step 20
20Replace the APP sensor assembly. Refer to Accelerator Pedal with Position Sensor Replacement . Did you complete the repair?Go to Step 25
21Did DTC P0120 set while performing Step 9?Go to DTC P0120Go to Step 22
22Inspect for poor connections at the harness connector of the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 25Go to Step 23
23Replace the TAC module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 25
24Repair the intermittent condition as necessary. Refer to Connector Repairs and Wiring Repairs . Did you complete the repair?Go to Step 25
25Clear 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 26
26Observe 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 DTC P0120 or U0107 is also set, refer to the appropriate DTC for further diagnosis.

DTC P2120

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

  1. 2: This step determines if a communication condition exists.
  2. 5: This step isolates an internal APP sensor failure. The condition may only occur at a certain accelerator pedal position. Monitoring the APP angles for sensor 2 and sensor 3 is an accurate way of verifying the actual position of the pedal. The APP angles for all 3 sensors should be within a few percent of each other. If the pedal is at rest, the APP angle for all 3 sensors should be 0 percent. If the pedal is fully depressed, all APP angles should be 100 percent.
  3. 6: The APP sensor 1 shares a common 5-volt reference circuit with the throttle position (TP) sensor 1. Monitoring the TP sensor 1 voltage aids in diagnosing the APP sensor 5-volt reference and low-reference circuits. If the scan tool displays near 0 volts, the circuits are OK.
  4. 9: With the TAC module still connected, this test will help determine a short to the signal circuit either within the TAC module or wiring.
  5. 10: This step determines whether the TAC module or a shorted circuit is causing the condition.
  6. 19: When the TAC module detects a condition within the TAC System, more than one TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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
2Is DTC U0107 also set?Go to DTC U0107Go to Step 3
3IMPORTANT: Do not depress the accelerator pedal. Start the engine. Observe the diagnostic trouble code (DTC) information with a scan tool. Did any other throttle actuator control (TAC) module or accelerator pedal position (APP) sensor DTC set except P1125?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 4
4Observe the APP Sensor Agree/Disagree parameters with a scan tool. Does the scan tool indicate Disagree for any of the APP Agree/Disagree parameters?Go to Step 6Go to Step 5
5Turn ON the ignition, with the engine OFF. Observe the APP sensor angles for both APP sensors with a scan tool. Slowly depress the accelerator pedal, stopping at 25, 50, 75, and 100 percent. Slowly release the accelerator pedal, stopping at 75, 50, 25, and 0 percent. Does the scan tool indicate APP sensor 1 angle within 10.5 percent of the APP sensor 2 angle during the above test?Go to Diagnostic AidsGo to Step 6
6Turn OFF the ignition. Disconnect the APP sensor harness connector. Connect a fused jumper between the APP sensor 1, 5-volt reference circuit and ground. Turn ON the ignition, with the engine OFF. Observe the Throttle Position (TP) Sensor 1 Voltage parameter with a scan tool. Does the scan tool indicate TP sensor 1 voltage at the specified value?0.0 VGo to Step 7Go to Step 11
7Connect a fused jumper between the APP sensor 1, 5-volt reference circuit and the APP sensor 1 low-reference circuit. Observe the TP Sensor 1 Voltage parameter with a scan tool. Does the scan tool indicate TP sensor 1 voltage at specified value?0.0 VGo to Step 8Go to Step 12
8Connect a fused jumper between the APP sensor 1 signal circuit and the APP sensor 1, 5-volt reference circuit. Observe the APP Sensor 1 Voltage parameter with a scan tool. Does the scan tool indicate APP sensor 1 voltage near the specified value?5.0 VGo to Step 14Go to Step 9
9Test for a short between the APP sensor 1 signal circuit and all other APP circuits at the APP sensor harness connector with a DMM. Does the DMM indicate a short to another circuit?Go to Step 10Go to Step 13
10Turn OFF the ignition. Disconnect both of the TAC module harness connectors. Test for a short between the APP sensor 1 signal circuit and all other APP circuits at the APP sensor harness connector with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 18Go to Step 15
11Turn OFF the ignition. Disconnect the TAC module harness connector containing the APP circuits. Test the APP sensor 1, 5-volt reference circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 18Go to Step 15
12Turn OFF the ignition. Disconnect the TAC module harness connector containing the APP circuits. Test the APP sensor 1 low-reference circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 18Go to Step 15
13Turn OFF the ignition. Disconnect the TAC module harness connector containing the APP circuits. Test the APP sensor 1 signal circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find an open or high resistance?Go to Step 18Go to Step 15
14Inspect for poor connections at the harness connector of the APP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 18Go to Step 16
15Inspect for poor connections at the harness connectors of the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 18Go to Step 17
16Replace the APP sensor assembly. Refer to Accelerator Pedal with Position Sensor Replacement . Did you complete the replacement?Go to Step 18
17Replace the TAC module. Refer to Control Module References for replacement, setup, and programming. 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) List - VehicleSystem OK
IMPORTANT
Do not depress the accelerator pedal.

DTC P2121

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

  1. 2: The throttle position (TP) sensor 2 and the APP sensor 2 share a common 5-volt reference source. Diagnose DTC P0220 first if P0220 is also set.
  2. 18: This test determines whether or not the TAC module can recognize a change in signal voltage.
  3. 19: There are 2 separate 5-volt reference sources within the TAC module. The TP sensor 1 and the APP sensor 1 share one 5-volt reference source. The TP sensor 2 and the APP sensor 2 share another common 5-volt reference source. This test determines whether the signal circuit is shorted to any one of the 5-volt reference circuits. If a short exists, the corresponding sensor voltage will be pulled low.
  4. 20: The previous step found the signal circuit and a 5-volt reference circuit shorted together. This test isolates whether the short is in the harness or within the TAC module.
  5. 26: When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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
2IMPORTANT: If DTC P0220 or U0107 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle and diagnose the applicable DTC first. Turn ON the ignition, with the engine OFF, and with your foot OFF of the accelerator pedal. Observe the Accelerator Pedal Position (APP) Sensor 2 Voltage parameter with a scan tool. Does the scan tool indicate APP sensor 2 voltage within the specified values?0.24-2.24 VGo to Step 3Go to Step 6
3Fully depress the accelerator pedal to the wide open throttle (WOT) position. Does the scan tool indicate APP sensor 2 voltage within the specified values?0.24-4.49 VGo to Step 4Go to Step 6
4Turn OFF the ignition for 15 seconds. Turn ON the ignition, with the engine OFF. Observe DTC info with a scan tool. Lightly touch and move the related engine wiring harnesses and connectors for the APP sensor while observing the DTC status. If the scan tool indicates this DTC failed this ignition during the above test, repair the intermittent condition as necessary. Refer to Wiring Repairs and Connector Repairs . Did you find and correct the condition?Go to Step 25Go to Step 5
5Slowly depress the accelerator pedal to WOT, then slowly return the pedal to closed throttle while observing the DTC status. Did the scan tool indicate this DTC failed this ignition during the above test?Go to Step 21Go to Diagnostic Aids
6Disconnect the APP sensor harness connector. Test the APP sensor 2 signal circuit for voltage with a DMM. Does the DMM indicate APP sensor 2 signal voltage within the specified values?3.94-6.06 VGo to Step 11Go to Step 7
7Turn OFF the ignition. Disconnect the throttle actuator control (TAC) module harness connector containing the APP sensor circuits. Turn ON the ignition, with the engine OFF. Test the APP sensor 2 signal circuit for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 8
8Test the APP sensor 2 signal circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 9
9Test the APP sensor 2 signal circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 10
10Test for a short between the APP sensor 2 signal circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 23
11Test the APP sensor 2, 5-volt reference circuit for voltage with a DMM. Does the DMM indicate voltage within the specified values?4.54-5.21 VGo to Step 16Go to Step 12
12Turn OFF the ignition. Disconnect the TAC module harness connector containing the APP sensor circuits. Turn ON the ignition, with the engine OFF. Test the APP sensor 2, 5-volt reference circuit for a short to voltage with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 13
13Test the APP sensor 2, 5-volt reference circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 14
14Test the APP sensor 2, 5-volt reference circuit for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 15
15Test for a short between the APP sensor 2, 5-volt reference circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 23
16Measure resistance with a DMM connected between the APP sensor 2 low reference circuit and the APP sensor 1 low reference circuit. Does the DMM indicate resistance within the specified values?0-5 ohmGo to Step 18Go to Step 17
17Turn OFF the ignition. Disconnect the TAC module harness connector containing the APP sensor circuits. Test the APP sensor 2 low reference circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 23
18Connect a fused jumper between the APP sensor 2 signal circuit and the APP sensor 2 low reference circuit at the APP sensor harness connector. Observe the APP Sensor 2 Voltage parameter with a scan tool. Does the scan tool indicate APP sensor 2 voltage at the specified value?0 VGo to Step 19Go to Step 23
19Observe the APP Sensor 1, APP Sensor 3 and TP Sensor 2 Voltage parameters with a scan tool. Connect a fused jumper between the APP sensor 2 signal circuit and the APP sensor 2 low reference circuit at the APP sensor harness connector. Did the scan tool indicate a change in voltage in any of the parameters observed during the above test?Go to Step 20Go to Step 21
20Turn OFF the ignition. Disconnect the TAC module harness connectors. Test for a short between the APP sensor 2 signal circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 25Go to Step 23
21Inspect for poor connections at the harness connector of the APP sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 25Go to Step 22
22Replace the APP sensor assembly. Refer to Accelerator Pedal with Position Sensor Replacement . Did you complete the replacement?Go to Step 25
23Inspect for poor connections at the harness connector of the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 25Go to Step 24
24Replace the TAC module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 25
25Clear 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 26
26Observe 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 DTC P0220 or U0107 is also set, refer to Diagnostic Trouble Code (DTC) List - Vehicle and diagnose the applicable DTC first.

DTC P2125

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

  1. 21: When the TAC module detects a condition within the TAC System, more than 1 TAC System related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
StepActionYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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
2Is DTC U0107 set?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 3
3Turn ON the ignition, with the engine OFF. Observe the Throttle Position (TP) Sensor 1 and 2 Agree/Disagree parameter with a scan tool. Does the scan tool TP Sensor 1 and 2 Agree/Disagree parameter indicate Disagree?Go to Step 5Go to Step 4
4Remove the air inlet duct from the throttle body. Disconnect the throttle body harness connector. Observe the TP sensor 1 and 2 with a scan tool. Slowly open the throttle blade to wide open throttle (WOT) and back to the closed throttle position several times by hand. Does the TP Sensor Agree/Disagree parameter change from Agree to Disagree during the above test?Go to Step 18Go to Step 20
5Disconnect the TP sensor harness connector. Disconnect the throttle actuator control (TAC) module harness connectors. Test the TP sensor 1, 5-volt reference circuit for resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 6
6Test for a short between the TP sensor 1, 5-volt reference circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 7
7Test the TP sensor 1 signal circuit for resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 8
8Test for a short between the TP sensor 1 signal circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 9
9Test the TP sensor 1 low-reference circuit for resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 10
10Test for a short between the TP sensor 1 low-reference circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 11
11Test the TP sensor 2, 5-volt reference circuit for resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 12
12Test for a short between the TP sensor 2, 5-volt reference circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 13
13Test the TP sensor 2 signal circuit for resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 14
14Test for a short between the TP sensor 2 signal circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 15
15Test the TP sensor 2 low-reference circuit for resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 16
16Test for a short between the TP sensor 2 low-reference circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 20Go to Step 17
17Inspect for an intermittent and for a poor connection at the harness connector of the TAC module. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 20Go to Step 18
18Inspect for an intermittent and for a poor connection at the harness connector of the throttle body. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 20Go to Step 19
19Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . 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 - VehicleSystem OK

DTC P2135

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

  1. 2: Any circuit faults on either APP sensor 1 or 2 will set one of the DTCs listed. Refer to the appropriate table for diagnosis.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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
2Observe the DTC information with a scan tool. Is DTC P0120, P0220, P0641, P0651, P2120, or P2125 also set?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 3
3Turn OFF the ignition. Disconnect the accelerator pedal position (APP) sensor electrical connector. Disconnect the powertrain control module (PCM). Use a DMM to measure the resistance of the following circuits for each of the APP sensors: The low reference circuit The signal circuit The 5-volt reference circuit Did any of the circuits measure more than the specified value?5 ohmGo to Step 5Go to Step 4
4Test for a short between any of the circuits in the APP sensor harness. Repair the circuit as necessary. Refer to Wiring Repairs . Did you find and correct the condition?Go to Step 7Go to Step 6
5Repair the high resistance in the circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 7
6Replace the APP sensor. Refer to Accelerator Pedal with Position Sensor Replacement . Did you complete the replacement?Go to Step 7
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) List - VehicleSystem OK

DTC P2138

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

  1. 2: This step tests the supply voltage circuit of the secondary fuel pump relay. The test lamp should illuminate as the primary fuel pump is commanded ON.
  2. 4: This step verifies the secondary fuel pump operation. Listen for an audible sound as the secondary fuel pump relay harness connector is jumpered.
  3. 5: This step verifies that there is adequate fuel in the rear fuel tank. The rear fuel tank sensor voltage must be above 1 volt in order to continue.
  4. 7: This step tests the secondary fuel pumps ability to transfer fuel. The rear fuel level sensor voltage should decrease while the secondary fuel pump is ON.
  5. 8: This step tests for a short to ground on the control circuit of the secondary fuel pump relay. If the test lamp illuminates, a short to ground is indicated.
  6. 9: This step tests for a short to voltage on the control circuit of the secondary fuel pump relay. If the test lamp illuminates, a short to voltage is indicated.
  7. 10: This step verifies the secondary fuel pump relay operation. An audible click should be heard as the secondary fuel pump relay control circuit is grounded. The secondary fuel pump should turn ON as the fuel pump relay control circuit is grounded.
StepActionValuesYesNo
Schematic Reference: Engine Controls Schematics Connector End View Reference: Powertrain Control Module (PCM) 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
2IMPORTANT: The fuel level must be between 25-50 percent to perform this diagnostic procedure. If the fuel level is not within this range, misdiagnosis will occur. Turn OFF the ignition. Remove the secondary fuel pump relay. Turn ON the ignition, with the engine OFF. Probe the secondary fuel pump relay coil supply circuit with a test lamp connected to a good ground. Command the fuel pump relay ON with a scan tool. Does the test lamp illuminate when the fuel pump relay is commanded ON?Go to Step 3Go to Step 22
3Probe the ignition voltage circuit of the secondary fuel pump relay, switch side, with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 4Go to Step 12
4Connect a 15-amp fused jumper wire between the ignition 1 voltage and secondary fuel pump supply voltage circuit of the secondary fuel pump relay harness connector. Does the secondary fuel pump turn ON?Go to Step 5Go to Step 16
5Turn OFF the ignition. Remove the jumper wire from the secondary fuel pump relay harness connector. Turn ON the ignition, with the engine OFF. Observe the rear fuel level voltage parameter with a scan tool. Is the rear fuel level sensor voltage above the specified value?1 VGo to Step 7Go to Step 6
6Add the specified amount of fuel to the fuel tank. Did you complete the action?19 L (5 gal)Go to Step 7
7Turn OFF the ignition. Connect a 15-amp fused jumper wire between the ignition 1 voltage circuit and the secondary fuel pump supply voltage circuit of the secondary fuel pump relay harness connector. Turn ON the ignition, with the engine OFF. Observe the rear fuel level sensor voltage parameter with a scan tool. Does the rear fuel level sensor voltage decrease as the secondary fuel pump is operating?Go to Step 8Go to Step 18
8Turn OFF the ignition. Remove the jumper wire from the secondary fuel pump relay harness connector. Turn ON the ignition, with the engine OFF. Probe the secondary fuel pump relay control circuit with a test lamp connected to B+. Does the test lamp illuminate?Go to Step 23Go to Step 9
9Probe the secondary fuel pump relay control circuit with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 27Go to Step 10
10Turn OFF the ignition. Jumper the following secondary fuel pump relay switch circuits from the secondary fuel pump relay to the secondary fuel pump relay harness connector: The ignition 1 voltage circuit The secondary fuel pump supply voltage circuit Jumper the secondary fuel pump relay coil supply circuit to B+. Turn ON the ignition, with the engine OFF. Jumper the control terminal of the secondary fuel pump relay to a good ground. Does the secondary fuel pump turn ON when the fuel pump relay control terminal is grounded?Go to Step 11Go to Step 19
11Test the secondary fuel pump relay control circuit for an open. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 31Go to Step 21
12Inspect the PCM 1 fuse. Is the PCM 1 fuse open?Go to Step 13Go to Step 25
13Test the ignition 1 voltage circuit of the secondary fuel pump relay for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 31Go to Step 14
14Test the voltage supply circuit of the secondary fuel pump for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 31Go to Step 15
15Turn OFF the ignition. Install a new fuse. Connect a 15-amp fused jumper wire between the ignition 1 voltage and the secondary fuel pump supply voltage circuit of the secondary fuel pump relay harness connector. Turn ON the ignition, with the engine OFF. Inspect the PCM 1 fuse. Is the fuse open?Go to Step 29Go to Testing for Intermittent Conditions and Poor Connections
16Lower the rear fuel tank. Refer to Fuel Tank Replacement (Pickup) or Fuel Tank Replacement (Cab/Chassis - Front) or Fuel Tank Replacement (Cab/Chassis - Rear) . Disconnect the secondary fuel pump harness connector. Probe the voltage supply circuit of the secondary fuel pump with a test lamp connected to a good ground. Does the test lamp illuminate?Go to Step 17Go to Step 26
17Probe the ground circuit of the secondary fuel pump with a test lamp connected to B+. Does the test lamp illuminate?Go to Step 20Go to Step 24
18Inspect the fuel line between the primary and secondary fuel tanks for a restriction. Did you find and correct the condition?Go to Step 31Go to Step 29
19Test for an intermittent and for a poor connection at the harness connector of the secondary fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 31Go to Step 28
20Test for an intermittent and for a poor connection at the harness connector of the secondary fuel pump. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 31Go to Step 29
21Test for an intermittent and for a poor connection at the harness connector of the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 31Go to Step 30
22Repair the open supply voltage circuit of the secondary fuel pump relay. Refer to Wiring Repairs . Did you complete the repair?Go to Step 31
23Repair the short to ground in the control circuit of the secondary fuel pump relay. Refer to Wiring Repairs . Did you complete the repair?Go to Step 31
24Repair the open ground circuit of the secondary fuel pump. Refer to Wiring Repairs . Did you complete the repair?Go to Step 31
25Repair the open ignition voltage circuit of the secondary fuel pump relay. Refer to Wiring Repairs . Did you complete the repair?Go to Step 31
26Repair the open supply voltage circuit of the secondary fuel pump. Refer to Wiring Repairs . Did you complete the repair?Go to Step 31
27Repair the short to voltage on the control circuit of the secondary fuel pump relay. Refer to Wiring Repairs . Did you complete the repair?Go to Step 31
28Replace the secondary fuel pump relay. Did you complete the replacement?Go to Step 31
29Replace the rear fuel sender assembly. Refer to Fuel Sender Assembly Replacement . Did you complete the replacement?Go to Step 31
30Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 31
31Clear 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 32
32Observe 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 fuel level must be between 25-50 percent to perform this diagnostic procedure. If the fuel level is not within this range, misdiagnosis will occur.

DTC P2636

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 Powertrain Control Module (PCM) Connector End Views
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
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. 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 Testing for Intermittent Conditions and Poor Connections
4Turn OFF the ignition. Disconnect the affected heated oxygen sensor (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 procedures: 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 procedures: 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 . 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 procedures: 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 procedures: 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 procedures: 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 procedures: 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 rich exhaust condition, a lean exhaust condition, or the HO2S may be contaminated. Inspect for the following conditions: NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice . A silicon contaminated HO2S Any water intrusion into the HO2S connector An exhaust leak between the HO2S and the engine Any vacuum leaks Engine oil contaminated with fuel An incorrect fuel pressure-Refer to Fuel System Diagnosis . Any lean or rich fuel injectors-Refer to Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool) or Alcohol/Contaminants-in-Fuel Diagnosis (With Special Tool) . 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 procedures: 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 powertrain control module (PCM). Refer to the following procedures: 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 PCM. Refer to Control Module References 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 - VehicleSystem OK
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 .

DTC P2A01 or P2A04

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

  1. 2: This step determines if the ignition relay is supplying a voltage to the ETC fuse.
  2. 5: Increasing the engine speed to 3,000 RPM aids in locating a shorted throttle actuator motor control circuit. Depending on the polarity of the throttle actuator motor transistors, this DTC may not set with a fault in the control circuits. The throttle actuator motor is a bi-directional DC motor. Raising the engine speed changes the polarity of the transistors in the throttle actuator motor. This occurs because one set of the transistors is low, 0 volts, and the other set is high, B+. Therefore, if one set of transistors is at a low voltage and the corresponding circuit is shorted low, DTC P1518 will not set. When the polarity of the transistors change, this DTC sets. If this DTC does not fail this ignition, continue to monitor this DTC status while moving related harnesses and connectors.
  3. 29: Locating and repairing an individual condition may correct more than one 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 - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Turn ON the ignition, with the engine OFF. Remove the cover from the underhood electrical center. Test both sides of the electronic temperature control (ETC) fuse with a test lamp connected to ground. Does the test lamp illuminate on at least one side of the fuse?Go to Step 3Go to Ignition Relay Diagnosis
3Turn OFF the ignition Test for voltage at the ETC fuse with a test lamp connected to ground. Does the test lamp illuminate?Go to Step 22Go to Step 4
4Connect a scan tool. Is DTC P0604 also set?Go to DTC P0601-P0607, P1600, P1621, P1627, P1680, P1681, P1683, or P2610Go to Step 5
5IMPORTANT: If the driver information center is displaying Reduced Engine Power, go to Step 6. Start the engine. Increase the engine speed to 3,000 RPM, if possible. Monitor the DTC Info option using the scan tool. Does the scan tool indicate this DTC failed this ignition?Go to Step 6Go to Diagnostic Aids
6Turn OFF the ignition. Disconnect the throttle actuator motor harness connector. Turn ON the ignition, with the engine OFF. Test for voltage at both throttle actuator motor control circuits with a DMM. Does the DMM indicate voltage on both circuits above the specified value?1 VGo to Step 12Go to Step 7
7Turn OFF the ignition. Disconnect the throttle actuator control (TAC) module connectors. Test both throttle actuator motor control circuits for continuity to ground with a DMM. Does the DMM indicate continuity to ground?Go to Step 10Go to Step 8
8Turn OFF the ignition. Remove the ETC fuse. Test the TAC side of the fuse terminal for continuity to ground with a DMM. Refer to Diagnostic Aids for terminal identification table. Does the DMM indicate continuity to ground?Go to Step 9Go to Step 11
9Disconnect the TAC module 16-way harness connector. Test the TAC side of the fuse terminal for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 24
10Disconnect the TAC module 16-way harness connector. Test the throttle actuator motor control circuits for a short to ground at the TAC module 16-way harness connector with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 24
11Turn OFF the ignition. Disconnect the TAC module 16-way harness connector. Test the TAC module ignition feed circuit for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 24
12Turn OFF the ignition. Disconnect the TAC module 16-way connector. Turn ON the ignition, with the engine OFF. Test for a short to voltage at both throttle actuator motor control circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 13
13Turn OFF the ignition. Disconnect the TAC module 10-way harness connector. Test for a short between each throttle actuator motor control circuit and all other TAC module circuits with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 14
14Test for an open or high resistance in the TAC module ground circuit with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 15
15Test for voltage on the serial data circuits at the TAC module 16-way harness connector with a DMM. Does the DMM indicate voltage within the specified values for both circuits?0-4.5 VGo to Step 16Go to Step 18
16Turn OFF the ignition. Test both serial data circuits at the TAC module 16-way harness connector for continuity to ground with a DMM. Does the DMM indicate OL for both circuits?Go to Step 20Go to Step 17
17Disconnect the powertrain control module (PCM) connector containing the TAC module serial data circuits. Test both serial data circuits at the TAC module 16-way connector for a short to ground with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 18
18Test for a short between both serial data circuits and all other circuits at the PCM and TAC module harness connectors with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 19
19Test for a short to voltage on both serial data circuits at the TAC module 16-way connector with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 25
20Disconnect the PCM connector that contains the TAC module serial data circuits. Test each serial data circuit between the TAC module 16-way harness connector and the PCM harness connector for an open or high resistance with a DMM. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 21
21Connect the PCM. Turn ON the ignition. Test for voltage on the serial data circuit at the TAC module 16-way harness connector with a DMM. Does the DMM indicate voltage at the specified value?0 VGo to Step 25Go to Step 24
22Turn OFF the ignition. Disconnect the 16-way TAC module harness connector. Test the TAC module ignition feed circuit for a short to battery voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 23
23Turn ON the ignition. Test both TAC motor circuits for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 28Go to Step 24
24Test for poor connections at the TAC module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 28Go to Step 26
25Test for poor connections at the PCM harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Repairing Connector Terminals . Did you find and correct the condition?Go to Step 28Go to Step 27
26Replace the TAC module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 28
27Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 28
28Clear 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 29
29Observe 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 driver information center is displaying Reduced Engine Power, go to Step 6.

DTC U0107

See also:
• Scan Tool Data List

More articles — Engine Controls - 8.1L - Diagnostics (Dtcs P0506-U0107)