DTC Troubleshooting

DTC Troubleshooting: P0406

DTC P0406: EGR Valve Position Sensor Circuit High Voltage

NOTE: Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information. Reading and Clearing Diagnostic Trouble Codes

1. Turn the ignition switch to ON (II).

2. Check the EGR VLS in the DATA LIST with the HDS.

Is 4.88 V or more indicated?
YES - Go to step 3.

NO - Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at the EGR valve and the PCM.


3. Turn the ignition switch to LOCK (0).

4. Disconnect the EGR valve 5P connector.

5. Turn the ignition switch to ON (II).

6. Measure the voltage between EGR valve 5P connector terminals No. 3 and No. 4.

Is there about 5 V?
YES - Go to step 8.

NO - Go to step 7.






7. Measure the voltage between PCM connector terminals C12 and C14.

Is there about 5 V?
YES - Repair open in the wire between the EGR valve and the PCM (C12), then go to step 10.

NO - Go to step 14.






8. Turn the ignition switch to LOCK (0).

9. Replace the EGR valve. Service and Repair

10. Turn the ignition switch to ON (II).

11. Reset the PCM with the HDS.

12. Do the PCM idle learn procedure. PCM Idle Learn Procedure

13. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0406 indicated?
YES - Check for poor connections or loose terminals at the EGR valve and the PCM, then go to step 1.

NO - Troubleshooting is complete. If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.


14. Reconnect all connectors.

15. Update the PCM if it does not have the latest software, PCM Update or substitute a known-good PCM. Reading and Clearing Diagnostic Trouble Codes

16. Check for Pending or Confirmed DTCs with the HDS.

Is DTC P0406 indicated?
YES - Check for poor connections or loose terminals at the EGR valve and the PCM. If the PCM was updated, substitute a known-good PCM, Reading and Clearing Diagnostic Trouble Codes then recheck. If the PCM was substituted, go to step 1.

NO - If the PCM was updated, troubleshooting is complete. If the PCM was substituted, replace the original PCM. Service and Repair If any other Pending or Confirmed DTCs are indicated, go to the indicated DTC's troubleshooting.