DTC P0401

DTC P0401  : EGR Insufficient Flow

DTC (PGM-FI)

1. EGR valve check

   -1. Turn the vehicle to the ON mode.

   -2. Clear the DTC with the HDS.

   -3. Start the engine. Hold the engine speed at 3000 RPM without load (in P or N) until the radiator fan comes on, then let it idle.

   -4. Do the EGR TEST with the HDS.

   EGR TEST

   Is the result OK?

   YES 

   Go to step 2.

   NO 

   Replace the EGR valve , then do the repair verification.

2. Problem verification

   -1. Test-drive under these conditions:

   • Engine coolant temperature (ECT SENSOR 1) above 158 deg.F (70 deg.C)
   • Transmission in D
   • Drive the vehicle at a steady speed between 15-75 mph (24-120 km/h) for at least 5 seconds
   • Drive the vehicle at a steady speed between 55-75 mph (90-120 km/h) for at least 10 seconds
   • During the drive, decelerate (with the throttle fully closed) for 4 seconds

   Signal	Current conditions
   	Values	Unit
   ECT SENSOR 1
   VEHICLE SPEED

   -2. Monitor the OBD STATUS for DTC P0401 in the DTCs MENU with the HDS.

   DTC Description	OBD STATUS
   P0401 EGR Insufficient Flow

   Does the HDS indicate FAILED?

   YES 

   Clean the intake manifold EGR port with throttle plate cleaner. Also clean the passage inside the EGR valve with throttle plate cleaner, then do the repair verification.

   NO 

   If the HDS indicates PASSED, intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the EGR valve and the PCM. If the HDS indicates EXECUTING, keep driving until a result comes on. If the HDS indicates OUT OF CONDITION, meet the test condition and recheck.

3. Repair verification (OBD STATUS check)

   -1. Turn the vehicle to the OFF (LOCK) mode.

   -2. Reconnect all connectors.

   -3. Turn the vehicle to the ON mode.

   -4. Reset the PCM with the HDS .

   Reset PCM

   -5. Do the PCM idle learn procedure .

   -6. Test-drive under these conditions:

   • Engine coolant temperature (ECT SENSOR 1) above 158 deg.F (70 deg.C)
   • Transmission in D
   • Drive the vehicle at a steady speed between 15-75 mph (24-120 km/h) for at least 5 seconds
   • Drive the vehicle at a steady speed between 55-75 mph (90-120 km/h) for at least 10 seconds
   • During the drive, decelerate (with the throttle fully closed) for 4 seconds

   Signal	Current conditions
   	Values	Unit
   ECT SENSOR 1
   VEHICLE SPEED

   -7. Monitor the OBD STATUS for DTC P0401 in the DTCs MENU with the HDS.

   DTC Description	OBD STATUS
   P0401 EGR Insufficient Flow

   DTC (PGM-FI)

   Does the HDS indicate PASSED, FAILED, EXECUTING, or OUT OF CONDITION?

   PASSED

   Troubleshooting is complete. If any other Pending or Confirmed DTCs were indicated, go to the indicated DTC's troubleshooting.

   FAILED

   Troubleshooting is incomplete. Go to step 1 and recheck.

   EXECUTING

   Keep the test conditions until a result comes on.

   OUT OF CONDITION

   Meet the test conditions, and check the OBD STATUS again.