EGR System Check (Chart C-7)

Chart C-7:

EGR VSV Circuit:

CIRCUIT DESCRIPTION:

The 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. The EGR vacuum switching valve allows exhaust gases to enter the intake manifold under high load conditions.

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

1. This test checks that the EGR valve is mechanically functional.

2. This test checks that vacuum is available to operate the EGR valve.

3. This test checks the EGR valve movement.

4. This test checks fora short to ground in LT GRN/YEL wire or a faulty ECM.

5. This test checks for a faulty EGR vacuum switching valve or a faulty ECM.

DIAGNOSTIC AIDS:

Be sure to check hoses for proper vacuum supply. Check hoses for being plugged, kinked, or deteriorated.