Chart C-7A Exhaust Gas Recirculation (EGR) Check

Diagnostic Chart:

Electrical Schematic:

CIRCUIT DESCRIPTION
The Exhaust Gas Recirculation Solenoid Vacuum (EGR SV) valve is controlled by the Engine Control Module (ECM). The EGR SV valve is supplied with battery voltage and the ECM will switch the ground to turn the solenoid "ON" for EGR operation.

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

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) 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 for a short to ground in LT GRN/WHT wire or a faulty ECM.
5. This test checks for a faulty EGR SV valve or a faulty ECM.

DIAGNOSTIC AIDS
Be sure to check hoses for proper vacuum supply, plugged, kinked or deteriorated hoses.

INTERMITTENT MALFUNCTIONS
An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.