Diagnostic Aids

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue and 2002 Oldsmobile Aurora. However, it is still accessible from the selected car via links, so may be relevant.

If EGR valve shows signs of excessive heat, check exhaust system for blockage or for a plugged catalytic converter. A vacuum restriction to the MAP sensor can cause EGR flow test to fail due to insufficient MAP changes being monitored during the test. An engine that is running poorly may cause this DTC to set. Check for poor connection or damaged wiring harness. If wiring harness appears to be okay, observe EGR position sensor display on scan tool while moving connectors and wiring harnesses that are related to EGR valve. A change in the display indicates location of malfunction.

To verify a repair, clear info with the scan tool and run the EGR flow test keeping the following items in mind:

PCM will only run EGR flow test during a gradual deceleration.
PCM will only run EGR test during a closed throttle condition.
PCM will only run EGR test with vehicle speeds at more than 23 MPH.
Several deceleration cycles will be necessary in order to run a sufficient number of EGR flow test samples. A sufficient number of samples is usually 5-15 samples.
The EGR Test Counter displayed on the scan tool can be useful in determining that EGR flow test is running and to keep track of the number of test samples taken. The counter will increment each time a test sample is taken.