Here's another code that Winger was asking about. This one I have seen a couple of times in 58,000 miles but it's never been a hard recurring code for me.
The purpose of this diagnostic is to check for a condition where EGR flow is higher than commanded. This algorithm runs at idle. The diagnostic closes the EGR valve, and limits the intake air throttle valve. It then looks at fresh air flow fraction and the difference in pressure between the exhaust manifold pressure sensor and boost pressure sensor to determine if the EGR valve is leaking.
The ECM will illuminate the MIL lamp after the diagnostic runs and fails in two consecutive drive cycles. The ECM will also illuminate the ETC lamp.
The MIL lamp will turn off once the diagnostic runs and passes in 4 consecutive drive cycles. - When Monitored: Engine running, Coolant temperature above a calibrated threshold, Intake Manifold temperature above a calibrated threshold, EGR valve is closed.
- Set Condition: When intake throttle is closed, EGR fraction increases more than a calibrated threshold.
Possible Causes
EXHAUST GAS PRESSURE SENSOR
EGR AIRFLOW THROTTLE CONTROL VALVE
EGR VALVE