DTC 51

EGR Circuit:

Code 51 Wiring Diagram:

CIRCUIT DESCRIPTION:

EGR Vacuum Switching Valve (VSV) solenoid is controlled by the ECM. The VSV solenoid is supplied with battery voltage and the ECM will switch to ground to turn the solenoid "ON" for EGR operation.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. This will check the circuit for a short to ground.

2. Check for voltage from main relay.

3. Checks the circuit for fault of Code or a faulty ECM.

4. A high resistance in solenoid coil could cause a Code 51.

5. Looking for a short to ground in GREEN wire or the ECM being the short to ground. Code 51 will set if:

^ System is in closed loop.
^ During periodic off cycle of VSV.
^ Manifold pressure change is less than a calibrated value.

DIAGNOSTIC AIDS:

A poor or loose connection at the ECM could cause an intermittent failure. This could cause a code to be set falsely.