Diagnostic Aids
WARNING: This page is about a different car, the 2003 GMC Savana and 2003 Chevrolet Chevy Express. However, it is still accessible from the selected car via links, so may be relevant.
Inspect for the following conditions:
- A vacuum restriction to the MAP sensor - A skewed MAP sensor reading can cause the PCM to read incorrect MAP changes during the EGR flow test.
- An engine that is running poorly due to a mechanical condition - These types of conditions can cause low engine vacuum and thus cause a higher than expected MAP sensor reading.
- Excessive back pressure in the exhaust system may cause this DTC to set. This condition can cause low engine vacuum and thus cause a higher than expected MAP sensor reading. Possible causes of this could be a restriction in the exhaust system or non Original Equipment Manufacture (OEM) exhaust parts.
- Exhaust system leaks can cause an insufficient amount of EGR flow through the EGR valve. This condition can cause less than expected MAP changes due to insufficient exhaust back pressure. Possible causes of this could be a leaking exhaust system, a leaking EGR pipe or non Original Equipment Manufacture (OEM) exhaust parts.