Diesel Data: Automotive Repair

P0401

DTC P0401: Insufficient Flow Detected in EGR System

1. Reset the ECM with the HDS.
2. Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on. Test-drive under these conditions:

- No any electrical loads.
- Decelerate from 55 mph (88 km/h) for at least 5 seconds.

3. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0401 indicated?

YES - Clean the intake manifold EGR port with carburetor cleaner. 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 with a jumper wire.
7. Start the engine, and let it idle, then connect battery negative terminal No. 6 with a jumper wire.

Did the engine stall or run rough?

YES - Intermittent failure, system is OK at this time.

NO - Clean the intake manifold EGR port with carburetor cleaner. Clean the passage inside the EGR valve with carburetor cleaner, or replace the EGR valve.