DTC Troubleshooting: P1401 (80-2)

DTC P1401:  EGR Insufficient Flow

1.Record this freeze data.
  • Engine speed
  • Vehicle speed

2.Check for a loose or damaged vacuum lines.

Are the lines OK?


YES - Go to 3.


NO - Repair or replace the damaged parts, then go to 19.


3.Clear the DTC with the HDS.

4.Start the engine. Hold the engine speed at 2,000 rpm (min-1) without load (in neutral) until the radiator fan comes on, then let it idle.

5.Do the EGR TEST in the INSPECTION MENU with the HDS.

Is the result OK?


YES - Go to 6.


NO - Go to 9.


6.Do the TURBOCHARGER BOOST TEST in the INSPECTION MENU with the HDS.

Is the result OK?


YES - Go to 7.


NO - Go to 14.


7.Test-drive the vehicle for several minutes in the range of the recorded freeze data.

8.Monitor the OBD STATUS for DTC P1401 in the DTCs MENU with the HDS.

Does the screen indicate FAILED?


YES - Replace the EGR valve, then go to 19.


NO - If the screen indicates PASSED, intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the EGR control solenoid valve, the turbocharger boost control solenoid and the ECM. If the screen indicates NOT COMPLETED, go to 7 and recheck.


9.Turn the ignition switch OFF.

10.Check for a loose or damaged these EGR valve control vacuum line:
  • The vacuum pump and the EGR control solenoid valve
  • The EGR control solenoid valve and the EGR valve control diaphragm

Is the line OK?


YES - Go to 11.


NO - Repair or replace the damaged hoses, then go to 19.


11.Disconnect the vacuum hose (A) from the EGR control solenoid valve (B), and connect a vacuum pump/gauge (C) to the solenoid.

 

12.Turn the ignition switch ON (II).

13.Apply vacuum to the hose.

Does the EGR valve control diaphragm operate?


YES - Replace the EGR control solenoid valve, then go to 19.


NO - Replace the EGR valve, then go to 19.


14.Turn the ignition switch OFF.

15.Check for a loose or damaged these turbo control vacuum line:
  • The vacuum pump and the turbocharger boost control solenoid
  • The turbocharger boost control solenoid and turbocharger boost control diaphragm

Is the line OK?


YES - Go to 16.


NO - Repair or replace the damaged hoses, then go to 19.


16.Disconnect the vacuum hose (A) from the tubocharger boost control solenoid (B), and connect a vacuum pump/gauge (C) to the solenoid.

 

17.Turn the ignition switch ON (II).

18.Apply vacuum to the hose.

Does the turbocharger boost control diaphragm operate?


YES - Replace the turbocharger boost control solenoid, then go to 19.


NO - Replace the turbocharger assembly, then go to 19.


19.Reconnect all hoses.

20.Turn the ignition switch ON (II).

21.Reset the ECM with the HDS.

22.Test-drive the vehicle for several minutes in the range of the recorded freeze data.

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

Are any Temporary DTCs or DTCs indicated?


YES - If DTC P1401 is indicated, check for poor connections or loose terminals at the EGR control solenoid valve, the turbocharger boost control solenoid and the ECM, then go to 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.


NO - Go to 24.


24.Monitor the OBD STATUS for DTC P1401 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?


YES - Troubleshooting is complete.n


NO - If the screen indicates FAILED, check for poor connections or loose terminals at the EGR control solenoid valve, the turbocharger boost control solenoid and the ECM, then go to 1. If the screen indicates NOT COMPLETED, go to 22 and recheck.