P2142

P2142-EGR AIRFLOW THROTTLE CONTROL CIRCUIT HIGH

For a complete wiring diagram Refer to Diagrams/Electrical.

Theory of Operation


The EGR Airflow Throttle is a smart device that is commanded by the ECM through a PWM signal. This is a completely modulated device. The ECM will light the MIL lamp immediately after this diagnostic runs and fails. The ECM will turn off the MIL lamp after the diagnostic runs and passes in 4 consecutive drive cycles.

- When Monitored:
Ignition on.

- Set Condition:
Status line feedback voltage is outside of a calibratable range.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Initial Inspection and Diagnostic Overview


Diagnostic Test


1. DTC STATUS
Turn the ignition on.
With the scan tool, read DTC's.
Is P2142 active?

Yes


- Go To 2


No


- Refer to the INTERMITTENT CONDITION Symptom. Intermittent Condition



2. EGR AIRFLOW CONTROL VALVE RETURN LINE OPEN
Turn the ignition off.
Disconnect the EGR Airflow Control Valve harness connector.
Disconnect the C1 ECM harness connector.
Measure the resistance between the return circuit in the EGR Airflow Control Valve connector to the return circuit in the C1 ECM harness connector.
Is the resistance less than 10 ohms?

Yes


- Go To 3


No


- Repair the open return circuit in the harness.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test



3. EGR AIRFLOW CONTROL VALVE STATUS LINE SHORTED
Measure the resistance between the EGR Airflow Control Valve status circuit at the ECM engine harness connector and ground.
Is the resistance greater than 100 kohms?

Yes


- Go To 4


No


- Repair the short circuit to ground
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test



4. EGR AIRFLOW CONTROL VALVE
Reconnect the C1 ECM harness connector.
Turn the ignition on.
With the scan tool, read DTC's.
Does DTC P2141 become active?

Yes


- Replace EGR Airflow Control Valve.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


No


- Replace ECM.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test