For 1990-2009 cars

### Circuit Description

The exhaust gas recirculation (EGR) valve consists of a pintle valve that moves by the use of an internal solenoid and an internal position sensor (potentiometer) used to determine pintle valve position. The ECM controls the solenoid by supplying it ground whenever exhaust gas needs to be recirculated into the intake manifold. When the solenoid is commanded Off (circuit not grounded), the voltage level at the ECM should be high (ignition voltage). When the solenoid is commanded On (circuit grounded), the voltage level at the ECM should be low. The ECM EGR solenoid feedback circuit uses a pull-up voltage (2.6-4.6 volts), which allows the ECM to individually differentiate between an open, short to ground or short to voltage. DTC P0489 will set if the ECM detects lower than normal feedback voltage when EGR solenoid is commanded Off with engine cranking/running.

### Conditions for Setting the DTC

DTC P0489 will set if EGR solenoid feedback voltage is less than 2.6 volts when EGR solenoid is commanded Off when:

• | Condition exists for longer than 0.5 seconds

• | Engine speed is greater than 40 rpm

• | Battery voltage is between 7.5 and 15.0 volts

DTC P0489 diagnostic runs continuously once the above conditions have been met.

P0489 is a type B DTC

### Diagnostic Aids

To locate an intermittent problem, use Scan tool to monitor DTC P0489 LAST TEST with engine running. Wiggling wires while watching for a change from PASSED to FAILED may locate the area where a short to ground in the wiring may exist.

If either circuit 251 is shorted to ground, DTC P0489 will set.

EGR solenoid resistance: 7-11 ohms

### DTC P0489