DTC P1401: EGR Insufficient Flow NOTE: If DTC P1236 is stored at the same time as DTC P1401, troubleshoot DTC P1236 first, then recheck for DTC P1401.

1. Turn the ignition switch ON (II).

1. Note this freeze data:
   - Engine speed
   - Vehicle speed

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 6 .
NO | - | Go to Step 20 .

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

Is the result OK?

YES | - | Go to Step 7 .
NO | - | Go to Step 9 .

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

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

Does the screen indicate FAILED?

YES | - | Go to Step 9 .
NO | - | If the screen indicates PASSED, intermittent failure, system is OK at this time. If the screen indicates NOT COMPLETED, go to Step 7 and recheck.

1. Turn the ignition switch OFF.

1. Check for a looseness or damage at these turbo control vacuum line:
   - The line between vacuum pump and turbocharger boost control solenoid
   - The line between turbocharger boost control solenoid and turbocharger boost control diaphragm

Is the line OK?

YES | - | Go to Step 11 .
NO | - | Repair or replace the damaged hoses, then go to Step 14 .

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

1. Turn the ignition switch ON (II), and apply vacuum to the hose.

Does the turbocharger boost control diaphragm operate?

YES | - | Replace the turbocharger boost control solenoid, then go to Step 14 .
NO | - | Go to Step 13 .

1. Replace the turbocharger assembly.

1. Reconnect all connectors and 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 the recorded freeze data.

1. 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 valve, turbocharger boost control solenoid and the ECM, then go to Step 1 . If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
NO | - | Go to Step 19 .

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

Does the screen indicate PASSED?

YES | - | Troubleshooting is complete.■
NO | - | If the screen indicates FAILED, check for poor connections or loose terminals at the EGR valve, turbocharger boost control solenoid and the ECM, then go to Step 1 . If the screen indicates NOT COMPLETED, go to Step 17 and recheck.

1. Check for damage or clogging at the EGR cooler.

Is the EGR cooler OK?

YES | - | Go to Step 21 .
NO | - | Replace the EGR cooler, then go to Step 15 .

1. Replace the EGR valve.

1. Reconnect all connectors and hoses.

1. Turn the ignition switch ON (II).

1. Reset the ECM 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 TURBOCHARGER BOOST TEST in the INSPECTION MENU with the HDS.

Is the result OK?

YES | - | Go to Step 17 .
NO | - | Go to Step 9 .