P0406

DTC P0406: EGR Valve Position Sensor Circuit High Voltage (2003 AT-PZEV (SULEV) and 2004-2005 models)

NOTE: Information marked with an asterisk (*) applies to 2003 ULEV model.

1. Reset the ECM with the HDS.
2. Start the engine.
3. Check for Temporary DTCs or DTCs with the HDS.

Is DTC P0406 (P1498)* indicated?

YES - Go to step 4.

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

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




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

Is there about 5 V?

YES - Replace the EGR valve.

NO - Go to step 8.




8. Measure voltage between ECM connector terminals A10 and A20.

Is there about 5 V?

YES - Repair open in the wire between the EGR valve and the ECM (A10).

NO - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.