The exhaust gas recirculation (EGR) value consists of a pintle valve that moves by the use of an internal solenoid and an internal position sensor (potentiometer) which used to determine pintle valve position. The EGR solenoid receives power through the main relay when the ignition key is in the crank or run position. The ECM controls the EGR solenoid by supplying a ground to the EGR solenoid whenever exhaust gas needs to be recirculated into the intake manifold. The EGR sensor signal voltage operating range is between .14 - 4.82 volts. The ECM monitors the EGR solenoid control feedback and EGR sensor signal (valve position) circuits for correct voltage levels at certain times. DTC P0406 will set if the EGR sensor signal is above a calibrated value for a certain length of time.

DTC P0406 will set if the EGR sensor signal is above 4.82 volts when:

DTC P0406 diagnostic runs continuously with the ignition On.

P0406 is a (type B) DTC.

To locate an intermittent problem, use the Scan tool to monitor EGR SENSOR with the ignition On, engine Off.

Wiggling wires while monitoring EGR SENSOR may locate the area where a short to voltage may exist.

Important: When DTC P0406 sets, some EGR functions will be disabled for the remainder of that ignition cycle. When repairs are complete, DTCs must be cleared and ignition keyed Off for at least 10 seconds to allow proper operation.

If DTCs P0103, P0108, P0113, P0118, P0123, P0223, P0341, P0406 and P1271 are set, there may be an open circuit in the 5 volt reference return circuit 652.