DTC Troubleshooting

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.

1. Turn the ignition switch 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, system is OK at this time. Check for poor connections or loose terminals at the EGR valve and the ECM/PCM.

3. Turn the ignition switch OFF.
4. Disconnect the EGR valve 6P connector.
5. Turn the ignition switch ON (II).




6. Measure voltage between EGR valve 6P connector terminals No. 2 and No. 3.

Is there about 5 V?

YES - Go to step 8.

NO - Go to step 7




7. Measure voltage between ECM/PCM connector terminals A20 and A23.

Is there about 5 V?

YES - Repair open in the wire between the EGR valve and ECM/PCM (A23), then go to step 10.

NO - Go to step 15.

8. Turn the ignition switch OFF.
9. Replace the EGR valve.
10. Reconnect all connectors.
11. Turn the ignition switch ON (II).
12. Reset the ECM/PCM with the HDS.
13. Do the ECM/PCM idle learn procedure.
14. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If Temporary DTC or DTC P0406 is indicated, check for poor connections or loose terminals at the EGR valve and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Troubleshooting is complete.

15. Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
16. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0406 indicated?

YES - Check for poor connections or loose terminals at the EGR valve and the ECM/PCM. If the ECM/PCM was updated, substitute a known-good ECM/PCM, then recheck. If the ECM/PCM was substituted, go to step 1.

NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.