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Engine Control System - 4.2L - DTC P0507 to P2401: Overview GMC Envoy II

Testing & Diagnostics ~1481 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 RPMs, 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 in Vehicle DTC Information
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 RPM control function. Does the engine speed correspond, within 100 RPM, with each command?Go to Intermittent ConditionsGo to Step 3
3Inspect for the following conditions: Vacuum leaks Excessive deposits in the throttle body A faulty positive crankcase ventilation (PCV) valve Did you find and correct the condition?Go to Step 4
4Clear 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 5
5Observe 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 P0507

Description

This diagnostic applies to internal microprocessor integrity conditions within the powertrain control module (PCM). This diagnostic also addresses if the PCM is not programmed.

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 Service Programming System (SPS) in Programming and Setup. Does DTC P0602 reset?Go to Step 4Go to Step 6
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 5Go to Step 6
5Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 6
6Clear 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 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 - Vehicle in Vehicle DTC InformationSystem OK

DTC P0601-P0607, P060E, P1600, P1621, P1627, P1681, P1683, or P2610

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

  1. 2: A DTC P0602 indicates that the PCM is not programmed.
  1. 5: Resistance is measured at the pedal assembly because a pedal resistance that is lower than the specified value will set this DTC.
StepActionValuesYesNo
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 8
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 7Go to Step 8
5Turn OFF the ignition. Disconnect the accelerator pedal connector Ensure that the pedal is at the rest position. Measure the resistance from the 5-volt reference of the accelerator pedal assembly to the accelerator pedal position (APP) sensor 2 signal of the accelerator pedal assembly with a DMM. Refer to Circuit Testing in Wiring Systems. Is the resistance less than the specified value?450 ohmsGo to Step 6Go to Step 7
6Replace the accelerator pedal assembly. Refer to Accelerator Pedal Position (APP) Sensor Replacement . Did you complete the replacement?Go to Step 8
7Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. 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. Did the DTC fail this ignition?Go to Step 2Go to Step 9
9Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK

DTC P060D

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

  1. 2: When the system is operating correctly, the HO2S 1 voltage should toggle above and below the specified values. You may need to operate the vehicle within the Freeze Frame conditions and Conditions for Setting the DTC in order to duplicate the malfunction that was detected by the PCM.
  2. 4: The specified value is what is measured on a correctly operating system.
  3. 5: The specified value is what is measured on a correctly operating system.
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 in Vehicle DTC Information
2IMPORTANT: If any other DTCs are set except for heated oxygen sensor (HO2S) DTCs, refer to the other DTCs first before proceeding with this table. Operate the engine at normal operating temperature. Operate the engine above 1,200 RPM for 2 minutes. Observe the HO2S 1 Voltage parameter with a scan tool. Does the scan tool indicate that the HO2S 1 voltage is varying above and below the specified values?250-500 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 HO2S 1. Turn ON the ignition, with the engine OFF. Measure the voltage of the HO2S 1 high signal circuit on the powertrain control module (PCM) side to a good ground with the DMM. Does the voltage measure within the specified range?350-550 mVGo to Step 5Go to Step 9
5Turn OFF the ignition. Connect a 3-amp fused jumper wire between the HO2S 1 high signal circuit and the HO2S 1 low signal circuit. Turn ON the ignition. Monitor the HO2S 1 voltage with the scan tool. Does the scan tool indicate that the HO2S 1 voltage is less than the specified value?20 mVGo to Step 6Go to Step 11
6Turn OFF the ignition. Remove the 3-amp fused jumper wire. Connect a test lamp between the ignition 1 voltage circuit and a good ground. DO NOT use the HO2S 1 heater low control. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate?Go to Step 7Go to Step 12
7Connect a test lamp between the ignition 1 voltage circuit and the HO2S 1 heater low control circuit. Turn ON the ignition, with the engine OFF. Command the HO2S 1 heater ON and OFF with the scan tool. Does the test lamp turn ON and OFF with each command?Go to Step 15Go to Step 8
8Does the test lamp remain illuminated with each command?Go to Step 13Go to Step 14
9Test the HO2S 1 high signal circuit for the following conditions: An open High resistance A short to ground A short to voltage Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 10
10Test the HO2S 1 low signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 17
11Test the HO2S 1 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 20Go to Step 17
12Test the ignition 1 voltage circuit for the following conditions: An open A short to ground High resistance Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Replace the O2 fuse, if necessary. Did you find and correct the condition?Go to Step 20Go to Step 16
13Test the HO2S 1 heater low control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 17
14Test the HO2S 1 heater low control circuit for the following conditions: An open A short to voltage High resistance Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 17
15IMPORTANT: Before replacing the HO2S 1, inspect and remove any source of contamination. Inspect for the following conditions: The use of incorrect silicon RTV sealant Fuel contamination An exhaust leak-Refer to Exhaust Leakage in Engine Exhaust. The HO2S is installed correctly Damaged wiring- Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 20Go to Step 16
16Inspect for poor connections at the harness connector of the HO2S 1. 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 20Go to Step 18
17Inspect for poor connections at the harness connector of 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 20Go to Step 19
18NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices. Replace the HO2S 1. Refer to Heated Oxygen Sensor Replacement - Position 1 .Did you complete the replacement?Go to Step 20
19Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 20
20Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 2Go to Step 21
21Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
If any other DTCs are set except for heated oxygen sensor (HO2S) DTCs, refer to the other DTCs first before proceeding with this table.
IMPORTANT
Before replacing the HO2S 1, inspect and remove any source of contamination.
NOTE
Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices.

DTC P1133

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

  1. 2: When the system is operating correctly, the HO2S 2 voltage should toggle above and below the bias voltage.
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 in Vehicle DTC Information
2Operate the engine at normal operating temperature. Operate the engine above 1,200 RPM for 2 minutes. Observe the Heated Oxygen Sensor (HO2S) 2 Voltage parameter with the scan tool. Does the scan tool indicate that the HO2S 2 voltage is less than the specified value?399 mVGo to Step 4Go to Step 3
3Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the HO2S 2 sensor. Turn ON the ignition, with the engine OFF. Measure the voltage of the HO2S 2 high signal circuit on the powertrain control module (PCM) side with the DMM. Does the voltage measure within the specified range?350-550 mVGo to Step 6Go to Step 5
5Test the HO2S 2 high signal circuit for a short to ground or a short to the low signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 8
6The HO2S 2 may be detecting a lean exhaust condition. Inspect for one of the following conditions: HO2S connector water intrusion An exhaust leak between the HO2S 2 and the engine-Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure- Refer to Fuel System Diagnosis . Lean fuel injectors-Refer to Fuel Injector Balance Test with Tech 2 . An inaccurate mass air flow (MAF) sensor Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition?Go to Step 11Go to Step 7
7Inspect for poor connections at the harness connector of the HO2S 2 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 11Go to Step 9
8Inspect for poor connections at the harness connector of 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 11Go to Step 10
9NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices. Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2 .Did you complete the replacement?Go to Step 11
10Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 11
11Clear 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 12
12Observe 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
NOTE
Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices.

DTC P1137

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

  1. 2: When the system is operating correctly, the HO2S 2 voltage should toggle above and below the specified values. You may need to operate the vehicle within the Freeze Frame conditions and Conditions for Setting the DTC in order to duplicate the malfunction that was detected by the PCM.
  2. 6: Disconnecting the HO2S 2 and connecting a jumper wire between the HO2S 2 high signal circuit and the HO2S 2 low signal circuit to ground, should cause the scan tool to display HO2S 2 voltage below 100 mV. If the signal voltage is still high, the this indicates that the PCM is malfunctioning.
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 in Vehicle DTC Information
2IMPORTANT: If any other DTCs are set except for heated oxygen sensor (HO2S) DTCs, refer to the other DTCs first before proceeding with this table. Operate the engine at normal operating temperature. Operate the engine above 1,200 RPM for 2 minutes. Observe the HO2S 2 Voltage parameter with a scan tool. Does the scan tool indicate that the HO2S 2 voltage is more than the specified value?648 mVGo to Step 4Go to Step 3
3Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the HO2S 2 sensor. Turn ON the ignition, with the engine OFF. Measure the voltage of the HO2S high signal circuit on the powertrain control module (PCM) side with a DMM. Does the voltage measure within the specified range?350-550 mVGo to Step 6Go to Step 5
5Test the HO2S 2 high signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 8
6The HO2S 2 is detecting a rich condition or may be contaminated. Inspect for the following conditions: HO2S connector water intrusion Silicon-contaminated HO2S 2 Fuel-contaminated engine oil Incorrect fuel pressure-Refer to Fuel System Diagnosis . A leaking fuel pressure regulator-Refer to Fuel System Diagnosis . Rich fuel injectors-Refer to Fuel Injector Balance Test with Tech 2 . Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition?Go to Step 11Go to Step 7
7Inspect for poor connections at the harness connector of the HO2S 2. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 9
8Inspect for poor connections at the harness connector of 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 11Go to Step 10
9NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices. Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2 .Did you complete the replacement?Go to Step 11
10Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 11
11Clear 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 12
12Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
If any other DTCs are set except for heated oxygen sensor (HO2S) DTCs, refer to the other DTCs first before proceeding with this table.
NOTE
Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices.

DTC P1138

System Description

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 temperatures 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.

If the PCM detects an HO2S voltage that stays below a specified value, DTC P1171 will set.

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

  1. 2: When the system is operating correctly, the HO2S 1 voltage should toggle above and below the bias voltage. You may need to operate the vehicle within the Freeze Frame conditions and Conditions for Setting the DTC in order to duplicate the malfunction that was detected by the PCM.
  2. 4: The specified value is what is measured on a correctly operating system.
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 in Vehicle DTC Information
2Operate the engine at normal operating temperature. Operate the engine above 1,200 RPM for 2 minutes. Observe the Heated Oxygen Sensor (HO2S) 1 Voltage parameter with a scan tool. Does the scan tool indicate that the HO2S 1 voltage is less than the specified value?300 mVGo to Step 4Go to Step 3
3Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 4Go to Diagnostic Aids
4Turn OFF the ignition. Disconnect the HO2S sensor. Turn ON the ignition, with the engine OFF. Measure the voltage of the HO2S 1 high signal circuit on the powertrain control module (PCM) side with the DMM. Does the voltage measure within the specified range?350-550 mVGo to Step 6Go to Step 5
5Test the HO2S 1 high signal circuit for a short to ground or a short to the HO2S 1 low signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 8
6The HO2S 1 is detecting a lean condition or may be contaminated. Inspect for the following conditions: HO2S connector water intrusion Silicon-contaminated HO2S An exhaust leak between the HO2S 1 and the engine. Refer to Exhaust Leakage in Engine Exhaust. Vacuum leaks Incorrect fuel pressure-Refer to Fuel System Diagnosis . Lean fuel injectors-Refer to Fuel Injector Balance Test with Tech 2 . Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition?Go to Step 11Go to Step 7
7Inspect for poor connections at the harness connector of the HO2S 1 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 11Go to Step 9
8Inspect for poor connections at the harness connector of 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 11Go to Step 10
9NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices. IMPORTANT: Before replacing the HO2S, determine and remove any source of contamination. Replace the HO2S 1. Refer to Heated Oxygen Sensor Replacement - Position 1 .Did you complete the replacement?Go to Step 11
10Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 11
11Clear 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 12
12Observe 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
NOTE
Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices.
IMPORTANT
Before replacing the HO2S, determine and remove any source of contamination.

DTC P1171

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 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.

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 serial data malfunction, DTC P1381 will set.

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 - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Does the scan tool display any anti-lock brake system (ABS) DTCs?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Symptoms - Anti-Lock Brake System in Anti-Lock Brake System

DTC P1381

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

  1. 8: The throttle valve is spring loaded in a slightly open position and should move in either direction without binding. The throttle valve should always be under spring pressure.
  2. 11: When the ignition is turned ON, the PCM operates the throttle control motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.
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
2Are DTCs P0120, P0220, P2120, P2125, P2135, P2138, also set?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 3
3IMPORTANT: The throttle angle and pedal angle may not correspond during this procedure. Turn ON the ignition, with the engine OFF. Observe the Throttle Position (TP) Sensor 1 and 2 Angle parameters. Apply and release the accelerator pedal several times. Does the TP Sensor 1 and 2 Angle parameters increase as the pedal is applied and decrease as the pedal is released?Go to Step 4Go to Step 5
4Observe the Freeze Frame/Failure Records for this DTC. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 5Go to Diagnostic Aids
5Turn ON the ignition, with the engine OFF. Probe both sides of the ETC fuse with a test lamp. Does the test lamp illuminate on both sides of the fuse?Go to Step 6Go to Step 16
6Turn OFF the ignition. Probe both sides of the electronic throttle control (ETC)/throttle actuator control (TAC) fuse with a test lamp. Does the test lamp illuminate on both sides of the fuse?Go to Step 22Go to Step 7
7Turn OFF the ignition. Disconnect the powertrain control module (PCM) connector containing the ETC/TAC ignition 1 voltage circuit. Turn ON the ignition. Probe the ETC/TAC ignition 1 voltage circuit with a test lamp. Does the test lamp illuminate?Go to Step 8Go to Step 23
8Turn OFF the ignition. Inspect the throttle body for the following conditions. Refer to Diagnostic Aids: A throttle valve that is NOT in the rest position A throttle valve that is binding open or closed A throttle valve that is free to move open or closed WITHOUT spring pressure. Did you find any of these conditions with the throttle body?Go to Step 24Go to Step 9
9IMPORTANT: The test lamp may momentarily flash when testing these circuits. This is considered normal. Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to ground. Did the test lamp illuminate and remain illuminated on either circuit?Go to Step 13Go to Step 10
10IMPORTANT: The test lamp may momentarily flash when testing these circuits. This is considered normal. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to battery positive.Did the test lamp illuminate and remain illuminated on either circuit?Go to Step 14Go to Step 11
11Turn OFF the ignition. Connect the test lamp between the TAC motor control 1 and battery ground. Observe the test lamp as you turn ON the ignition. Does the test lamp flash ON and then turn OFF?Go to Step 12Go to Step 15
12Turn OFF the ignition. Connect a test lamp between the TAC motor control 2 circuit and battery ground. Observe the test lamp as you turn ON the ignition. Does the test lamp flash ON and then OFF?Go to Step 18Go to Step 15
13Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor control circuits. Turn ON the ignition, with the engine OFF. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to ground. Does the test lamp illuminate?Go to Step 20Go to Step 19
14Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor control circuits. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to battery positive. Does the test lamp illuminate?Go to Step 21Go to Step 19
15Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor controls circuits. Test TAC motor control 1 and 2 circuits for an open or high resistance. Repair the circuit as necessary. Refer to Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 19
16Test the ETC/TAC ignition 1 voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 17
17Test the motor control 1 circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 24
18Test for a poor connection or terminal tension at the throttle body connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 26Go to Step 24
19Test for a poor connection or terminal tension 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 26Go to Step 25
20Repair the short to voltage on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
21Repair the short to ground on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
22Repair the short to voltage on the ETC ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
23Repair the open or high resistance in the ETC ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
24Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 26
25Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 26
26Clear 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 27
27Observe 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 throttle angle and pedal angle may not correspond during this procedure.
IMPORTANT
The test lamp may momentarily flash when testing these circuits. This is considered normal.
IMPORTANT
The test lamp may momentarily flash when testing these circuits. This is considered normal.

DTC P1516

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

  1. 8: The throttle valve is spring loaded in a slightly open position and should move in either direction without binding. The throttle valve should always be under spring pressure.
  2. 11: When the ignition is turned ON, the PCM operates the throttle control motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.
StepActionYesNo
Schematic Reference: Engine Controls Schematics
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle
2Are DTCs P0120, P0220, P2120, P2125, P2135, P2138 also set?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 3
3IMPORTANT: The throttle angle and pedal angle may not correspond during this procedure. Turn ON the ignition, with the engine OFF. Observe the Throttle Position (TP) Sensor 1 and 2 Angle parameters. Apply and release the accelerator pedal several times. Does the TP Sensor 1 and 2 Angle parameters increase as the pedal is applied and decrease as the pedal is released?Go to Step 4Go to Step 5
4Observe the Freeze Frame/Failure Records for this DTC. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 5Go to Diagnostic Aids
5Turn ON the ignition, with the engine OFF. Probe both sides of the TAC fuse with a test lamp. Does the test lamp illuminate on both sides of the fuse?Go to Step 6Go to Step 16
6Turn OFF the ignition. Probe both sides of the throttle actuator control (TAC) fuse with a test lamp. Does the test lamp illuminate on both sides of the fuse?Go to Step 22Go to Step 7
7Turn OFF the ignition. Disconnect the powertrain control module (PCM) connector containing the TAC ignition 1 voltage circuit. Turn ON the ignition. Probe the TAC ignition 1 voltage circuit with a test lamp. Does the test lamp illuminate?Go to Step 8Go to Step 23
8Connect the PCM. Turn OFF the ignition. Inspect the throttle body for the following conditions. Refer to Diagnostic Aids: A throttle valve that is NOT in the rest position A throttle valve that is binding open or closed A throttle valve that is free to move open or closed WITHOUT spring pressure. Did you find any of these conditions with the throttle body?Go to Step 24Go to Step 9
9IMPORTANT: The test lamp may momentarily flash when testing these circuits. This is considered normal. Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to ground. Did the test lamp illuminate and remain illuminated on either circuit?Go to Step 13Go to Step 10
10IMPORTANT: The test lamp may momentarily flash when testing these circuits. This is considered normal. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to battery positive.Did the test lamp illuminate and remain illuminated on either circuit?Go to Step 14Go to Step 11
11Turn OFF the ignition. Connect the test lamp between the TAC motor control 1 and battery ground. Observe the test lamp as you turn ON the ignition. Does the test lamp flash ON and then turn OFF?Go to Step 12Go to Step 15
12Turn OFF the ignition. Connect a test lamp between the TAC motor control 2 circuit and battery ground. Observe the test lamp as you turn ON the ignition. Does the test lamp flash ON and then OFF?Go to Step 18Go to Step 15
13Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor control circuits. Turn ON the ignition, with the engine OFF. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to ground. Does the test lamp illuminate?Go to Step 20Go to Step 19
14Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor control circuits. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to battery positive. Does the test lamp illuminate?Go to Step 21Go to Step 19
15Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor control circuits. Test the TAC motor control 1 and 2 circuits for an open or high resistance. Repair the circuit as necessary. Refer to Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 19
16Test the ETC ignition 1 voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 17
17Test the motor control 1 circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 24
18Test for a poor connection or terminal tension at the throttle body connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 26Go to Step 24
19Test for a poor connection or terminal tension 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 26Go to Step 24
20Repair the short to voltage on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
21Repair the short to ground on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
22Repair the short to voltage on the ETC ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
23Repair the open or high resistance in the ETC ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
24Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 26
25Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 26
26Clear 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 27
27Observe 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 throttle angle and pedal angle may not correspond during this procedure.
IMPORTANT
The test lamp may momentarily flash when testing these circuits. This is considered normal.
IMPORTANT
The test lamp may momentarily flash when testing these circuits. This is considered normal.

DTC P2101

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

  1. 8: More than 1 ETC 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. Keep this in mind when reviewing captured DTC 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 in Vehicle DTC Information
2Are any other DTCs set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Turn OFF the ignition for 15 seconds. Turn ON the ignition, with the engine OFF. Allow the pedal to rest at idle stop for 20 seconds. Observe the indicated throttle position parameter with a scan tool. Does the scan tool indicate throttle position within the specified values?10.8-23.2%Go to Step 6Go to Step 4
4Remove the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you find any obstructions preventing the throttle blade from returning to the default position?Go to Step 5Go to Step 6
5Remove the obstruction. Did you complete the repair?Go to Step 7
6Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 7
7Use the scan tool in order to clear the DTCs. 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 - Vehicle in Vehicle DTC InformationSystem OK

DTC P2119

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

  1. 6: This step checks the integrity of the 5-volt reference and ground circuits of the TP sensors.
  2. 7: This step determines if the 5-volt reference circuit or the sensor ground circuit is the cause of the DTC.
  3. 8: If the scan tool displays 100 percent for the TP sensor 1 and the TP sensor 2 angle, this indicates that the TP sensor signal circuits are not the cause of the DTC.
  4. 9: This step checks for excessive resistance in the TP sensor 5-volt reference circuit between the TP sensor harness connector and the PCM harness connector.
  5. 10: This step checks for excessive resistance in the TP sensor ground circuit between the TP sensor harness connector and the PCM harness connector.
  6. 11: This step checks for the TP sensor signal circuits for being shorted to another circuit in the PCM wiring harness between the PCM and the TP sensor wiring harness.
  7. 16: When the PCM detects a problem within the throttle control system, more than one related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual problem may correct more than one DTC. Keep this in mind when reviewing captured DTC info.
StepActionValue(s)YesNo
1Did you perform the Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Observe the DTC information, with a scan tool. Is DTC P0641 or P0651 also set?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationGo to Step 3
3Turn ON the ignition, with the engine OFF. Monitor the Throttle Position (TP) Sensors Agree/Disagree parameter using the scan tool. Does the scan tool indicate Disagree?Go to Step 6Go to Step 4
4Remove the resonator assembly from the throttle body assembly. IMPORTANT: Removing the throttle actuator control (TAC) fuse will set additional DTCs. Remove the TAC fuse. Open the throttle blade to wide open throttle (WOT) by hand and then return it to closed throttle. Stop briefly at approximately 25 percent, 50 percent, 75 percent and 100 percent in each direction. Test the Throttle Sensors Disagree parameter at each stop. Does the scan tool indicate Disagree while rotating the throttle blade?Go to Step 6Go to Step 5
5Observe 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. Does the DTC fail this ignition?Go to Step 15Go to Intermittent Conditions
6Disconnect the TP sensor electrical connector. Turn ON the ignition, with the engine OFF. Measure the voltage between the 5-volt reference circuit of TP sensor 1 and the TP sensor 1 low reference circuit with a DMM. Measure the voltage between the 5-volt reference circuit of TP sensor 2 and the TP sensor 2 low reference circuit with a DMM. Does the DMM display a voltage within the specified range for both measurements?4.9-5.1 VGo to Step 8Go to Step 7
7Test the voltage on the 5-volt reference circuit for TP sensor 1 and TP sensor 2 to a battery ground with a DMM. Does the DMM display a voltage within the specified range?4.9-5.1 VGo to Step 10Go to Step 9
8Observe the TP sensor 1 and TP sensor 2 angle on the scan tool. Does the scan tool indicate both sensors at the specified value?100%Go to Step 12Go to Step 9
9Test the 5-volt reference circuit of the TP sensor 1 and TP sensor 2 for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 10
10Test the low reference circuit of the TP sensor 1 and TP sensor 2 for high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 11
11Test the signal circuit of the TP sensor 1 and TP sensor 2 for high resistance. Did you find and correct the condition?Go to Step 15Go to Step 13
12Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 15
13Test for poor connections and/or terminal tension at the TP sensor and at the powertrain control module (PCM). Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition?Go to Step 15Go to Step 14
14Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 15
15Clear 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 16
16Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem OK
IMPORTANT
Removing the throttle actuator control (TAC) fuse will set additional DTCs.

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 in Vehicle DTC Information
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 - Vehicle in Vehicle DTC InformationGo 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 ohmsGo 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 in Wiring Systems. 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 in Wiring Systems. Did you complete the repair?Go to Step 7
6Replace the APP sensor. Refer to Accelerator Pedal Position (APP) 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 - Vehicle in Vehicle DTC InformationSystem OK

DTC P2138

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

  1. 8: The throttle valve is spring loaded in a slightly open position and should move in either direction without binding. The throttle valve should always be under spring pressure.
  2. 11: When the ignition is turned ON, the PCM operates the throttle control motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.
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
2Are DTCs P0120, P0220, P2120, P2125, P2135, P2138 also set?Go to Diagnostic Trouble Code (DTC) List - VehicleGo to Step 3
3IMPORTANT: The throttle angle and pedal angle may not correspond during this procedure. Turn ON the ignition, with the engine OFF. Observe the Throttle Position (TP) Sensor 1 and 2 Angle parameters. Apply and release the accelerator pedal several times. Does the TP Sensor 1 and 2 Angle parameters increase as the pedal is applied and decrease as the pedal is released?Go to Step 4Go to Step 5
4Observe the Freeze Frame/Failure Records for this DTC. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 5Go to Diagnostic Aids
5Turn ON the ignition, with the engine OFF. Probe both sides of the throttle actuator control (TAC) fuse with a test lamp. Does the test lamp illuminate on both sides of the fuse?Go to Step 6Go to Step 16
6Turn OFF the ignition. Probe both sides of the TAC fuse with a test lamp. Does the test lamp illuminate on both sides of the fuse?Go to Step 22Go to Step 7
7Turn OFF the ignition. Disconnect the powertrain control module (PCM) connector containing the TAC ignition 1 voltage circuit. Turn ON the ignition. Probe the TAC ignition 1 voltage circuit with a test lamp. Does the test lamp illuminate?Go to Step 8Go to Step 23
8Turn OFF the ignition. Inspect the throttle body for the following conditions. Refer to Diagnostic Aids: A throttle valve that is NOT in the rest position A throttle valve that is binding open or closed A throttle valve that is free to move open or closed WITHOUT spring pressure Did you find any of these conditions with the throttle body?Go to Step 24Go to Step 9
9IMPORTANT: The test lamp may momentarily flash when testing these circuits. This is considered normal. Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to ground. Did the test lamp illuminate and remain illuminated on either circuit?Go to Step 13Go to Step 10
10IMPORTANT: The test lamp may momentarily flash when testing these circuits. This is considered normal. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to battery positive.Did the test lamp illuminate and remain illuminated on either circuit?Go to Step 14Go to Step 11
11Turn OFF the ignition. Connect the test lamp between the TAC motor control 1 and battery ground. Observe the test lamp as you turn ON the ignition. Does the test lamp flash ON and then turn OFF?Go to Step 12Go to Step 15
12Turn OFF the ignition. Connect a test lamp between the TAC motor control 2 circuit and battery ground. Observe the test lamp as you turn ON the ignition. Does the test lamp flash ON and then OFF?Go to Step 18Go to Step 15
13Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor control circuits. Turn ON the ignition, with the engine OFF. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to ground. Does the test lamp illuminate?Go to Step 20Go to Step 19
14Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor control circuits. Probe the TAC motor control 1 and 2 circuits with the test lamp connected to battery positive. Does the test lamp illuminate?Go to Step 21Go to Step 19
15Turn OFF the ignition. Disconnect the PCM connector that contains the TAC motor controls circuits. Test TAC motor control 1 and 2 circuits for an open or high resistance. Repair the circuit as necessary. Refer to Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 19
16Test the ETC ignition 1 voltage circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 17
17Test the motor control 1 circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?Go to Step 26Go to Step 24
18Test for a poor connection or terminal tension at the throttle body connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?Go to Step 26Go to Step 24
19Test for a poor connection or terminal tension 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 26Go to Step 24
20Repair the short to voltage on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
21Repair the short to ground on the circuit where the test lamp remained illuminated. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
22Repair the short to voltage on the ETC ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
23Repair the open or high resistance in the ETC ignition 1 voltage circuit. Refer to Wiring Repairs . Did you complete the repair?Go to Step 26
24Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement . Did you complete the replacement?Go to Step 26
25Replace the PCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement?Go to Step 26
26Clear 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 27
27Observe 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 throttle angle and pedal angle may not correspond during this procedure.
IMPORTANT
The test lamp may momentarily flash when testing these circuits. This is considered normal.
IMPORTANT
The test lamp may momentarily flash when testing these circuits. This is considered normal.

DTC P2176

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

  1. 2: If the voltage does not change more that 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 in Vehicle DTC Information
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 Heated Oxygen Sensor (HO2S) 2 Voltage parameter with a scan tool, quickly cycle the throttle from closed throttle to wide open throttle, 3 times. Did the HO2S 2 Voltage parameter change more than the specified value?200 mVGo to Step 3Go to Step 4
3Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 4Go to Intermittent Conditions
4Turn OFF the ignition. Disconnect the HO2S 2. Turn ON the ignition, with the engine OFF. Observe the HO2S 2 Voltage parameter with a scan tool. Is the HO2S 2 Voltage parameter less than the specified value?100 mVGo to Step 6Go to Step 5
5Observe the HO2S 2 Voltage parameter with a scan tool. Is the HO2S 2 Voltage parameter more than the specified value?800 mVGo to Step 7Go to Step 8
6Test the HO2S 2 high signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 21Go to Step 9
7IMPORTANT: The sensor may be damaged if the circuit is shorted to a voltage source. Test the HO2S 2 high signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.Did you find and correct the condition?Go to Step 21Go to Step 18
8Measure the voltage from the low signal circuit of the HO2S 2 harness connector on the engine harness side to a good ground with a DMM. Refer to Circuit Testing in Wiring Systems. Is the voltage more than the specified value?2 VGo to Step 10Go to Step 11
9Test the HO2S 2 high signal circuit for a short to the HO2S 2 low signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 21Go to Step 18
10Test the HO2S 2 low signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 21Go to Step 18
11Connect a 3-amp fused jumper wire between the high signal circuit of the HO2S 2 harness connector on the engine harness side and a good ground. Observe the HO2S 2 voltage parameter with a scan tool. Is the HO2S 2 voltage parameter less than the specified value?100 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 2 harness connector on the engine harness side and the low signal circuit of the HO2S 2 harness connector on the engine harness side. Observe the HO2S 2 Voltage parameter with a scan tool. Is the HO2S 2 Voltage parameter less than the specified value?100 mVGo to Step 15Go to Step 13
13Test the HO2S 2 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 21Go to Step 18
14Test the HO2S 2 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 21Go to Step 18
15Test the HO2S 2 heater low control circuit for a short to the HO2S 2 high signal circuit or HO2S 2 low signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 21Go to Step 16
16The HO2S 2 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 in Cautions and Notices. A silicon contaminated HO2S 2 Any water intrusion into the HO2S 2 connector An exhaust leak between the HO2S 2 and the engine Any vacuum leaks Engine oil contaminated with fuel An incorrect fuel pressure-Refer to Fuel System Diagnosis . Any lean or rich fuel injectors-Refer to Fuel Injector Balance Test with Special Tool . Repair any of the above or similar engine conditions as necessary. Did you find and correct the condition?Go to Step 21Go to Step 17
17Test for shorted terminals and for poor connections at the HO2S 2. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 21Go to Step 19
18Test 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 21Go to Step 20
19NOTE: Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices. Replace the HO2S 2. Refer to Heated Oxygen Sensor Replacement - Position 2 .Did you complete the replacement?Go to Step 21
20Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 21
21Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?Go to Step 2Go to Step 22
22Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed?Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC InformationSystem 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 in Cautions and Notices.
NOTE
Refer to Heated Oxygen Sensor (HO2S) Resistance Learn Reset Notice in Cautions and Notices.

DTC P2401

See also:
Scan Tool Data List