Code p0401

Vehicle Application: 2000 Chevrolet Impala 3.4L, Vin E 2002 Chevrolet Impala 3.4L, Vin E 2000 Oldsmobile Silhouette 3.4L Customer Concern: Repeat Powertrain Control Module (PCM) code P0401. Carbon clean fixed. Tests/Procedures: 1. Watch the EGR desired and actual positions while driving. 2. The values should match within 5%. 3. If OK, perform the following carbon clean procedure. 4. Remove the EGR valve. 5. Run the engine until operating temperature is reached. 6. Install a metal funnel in the intake EGR port. 7. Slowly pour Top Engine Cleaner (TEC) into the intake port. NOTE: Do not pour the cleaner into the engine too quickly, it could cause engine damage due to hydro-lock. 8. Shut the engine off when the full 1 pint can has been ingested. 9. Move the funnel over to the exhaust port. 10. Pour a second 1 pint can of TEC into the exhaust EGR port. 11. Let the vehicle sit for 6-8 hours or longer. 12. Connect a speedometer cable into a drill. Have the other end cut and frayed. 13. Spin the cable in the EGR passages to scrape the carbon from the passages. 14. Cover the ports with a rag. 15. Start the engine, rev a couple of times, shut the engine off. 16. Install the EGR valve, road test. Potential Causes: Carbon Exhaust Gas Recirculation (EGR) Wiring Diagnostic Codes: P0401