P0402

Steps 1 - 3:

Steps 4 - 5:

DTC P0402 Exhaust Gas Recirculation (EGR) Excessive Flow Detected




Circuit Description
The Powertrain Control Module (PCM) closes the Exhaust Gas Recirculation (EGR) system on engine start-up to test for excessive (any) flow. If the PCM determines that EGR flow occurred on start-up, in two consecutive trips, then DTC P0402 will set. DTC P0402 is a type B code.

Conditions for Setting the DTC
- Intake Air Temperature (IAT) is above 5 °C (41 °F).
- Engine RPM is less than 500 RPM.
- EGR Pintle Position if greater than 55 counts.

The above mentioned conditions must be met for 0.6 seconds during engine start-up on two consecutive trips.

Diagnostic Aids
Check for the following conditions:
- Poor connection or damaged harness - Inspect the wiring harness for damage. If the harness appears to be OK, observe the Actual EGR Position display on the Scan Tool while moving connectors and wiring harnesses related to the EGR valve. A change in the display will indicate the location of the fault.
- Ensure EGR valve is correctly mounted. See On-Vehicle Service.

Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

NOTE: If the EGR valve shows signs of excessive heat, check the exhaust system for blockage (possible a plugged catalytic converter) using the "Restricted Exhaust System Check."