DTC Troubleshooting: P1401 (80)
DTC P1401:
 EGR Insufficient Flow
NOTE: Before you troubleshoot, record all freeze data and review the general troubleshooting information.
  1. Check for a loose or damaged vacuum lines.
Are the lines OK?
YES -
Go to Step 2 .
NO -
Repair or replace the damaged parts, then go to Step 16 .
  1. Clear the DTC with the HDS.
  1. 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.
  1. Do the EGR TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES -
Go to Step 5 .
NO -
Go to Step 8 .
  1. Do the TURBOCHARGER BOOST TEST in the INSPECTION MENU with the HDS.
Is the result OK?
YES -
Go to Step 6 .
NO -
Go to Step 12 .
  1. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
  1. Monitor the OBD STATUS for DTC P1401 in the DTCs MENU with the HDS.
Does the screen indicate FAILED?
YES -
NO -
If the screen indicates PASSED, intermittent failure, the 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 Step 6 and recheck.
  1. Turn the ignition switch OFF.
  1. Check for a loose or damaged these EGR valve control vacuum lines:
    • The vacuum pump and the EGR control solenoid valve
    • The EGR control solenoid valve and the EGR valve control diaphragm
Are the lines OK?
YES -
Go to Step 10 .
NO -
Repair or replace the damaged hoses, then go to Step 16 .
  1. Disconnect the vacuum hose (A) from the EGR control solenoid valve (B), and connect a vacuum pump/gauge (C) to the solenoid.
  1. Apply vacuum to the hose.
Does the EGR valve control diaphragm operate?
YES -
NO -
  1. Turn the ignition switch OFF.
  1. Check for a loose or damaged these turbo control vacuum lines:
    • The vacuum pump and the turbocharger boost control solenoid
    • The turbocharger boost control solenoid and turbocharger boost control diaphragm
Are the lines OK?
YES -
Go to Step 14 .
NO -
Repair or replace the damaged hoses, then go to Step 16 .
  1. Disconnect the vacuum hose (A) from the turbocharger boost control solenoid (B), and connect a vacuum pump/gauge (C) to the solenoid.
  1. Apply vacuum to the hose.
Does the turbocharger boost control diaphragm operate?
YES -
NO -
  1. Reconnect all hoses.
  1. Turn the ignition switch ON (II).
  1. Reset the ECM with the HDS.
  1. Test-drive the vehicle for several minutes in the range of these recorded freeze data parameters:
    • ENGINE SPEED
    • VSS
  1. Check for Temporary DTCs or DTCs with the HDS.
Is DTC P1401 indicated?
YES -
Check for poor connections or loose terminals at the EGR control solenoid valve, the turbocharger boost control solenoid, and the ECM, then go to Step 1 .
NO -
Go to Step 21 .
  1. Monitor the OBD STATUS for DTC P1401 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
YES -
Troubleshooting is complete. If any other Temporary DTCs or DTCs were indicated in Step 21 , go to the indicated DTC's troubleshooting.■
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 Step 1 . If the screen indicates NOT COMPLETED, go to Step 21 .