P0401
DTC P0401: EGR System Insufficient Flow1. Reset the PCM.
2. Test-drive under the following conditions.
- Without any electrical load.
- Decelerate from 55 mph (88 km/h) for at least 5 seconds.
3. Check for a Temporary DTC with the scan tool.
Is Temporary DTC P0401 indicated?
YES - Do these things.
- Clean the EGR passages under the upper intake cover with carburetor cleaner.
- Replace the upper intake cover gasket.
Make sure the tab on the gasket is at the rear of the head, and that the tab is visible on the throttle body end.
- Clean the passage inside the EGR valve with carburetor cleaner, or replace the EGR valve.
NO - Intermittent failure, go to step 4.
4. Turn the ignition switch OFF.
5. Disconnect the EGR valve 6P connector.
6. Connect the battery positive terminal to EGR valve connector terminal No.4.
7. Start the engine and let it idle, then connect the battery negative terminal to EGR valve connector terminal No.6.
Did the engine stall or run rough?
YES - Intermittent failure, system is OK at this time.
NO - Do these things.
- Clean the EGR passages under the upper intake cover with carburetor cleaner.
- Replace the upper intake cover gasket.
Make sure the tab on the gasket is at the rear of the head, and that the tab is visible on the throttle body end.
- Clean the passage inside the EGR valve with carburetor cleaner, or replace the EGR valve.