Exhaust Gas Recirculation: Testing and Inspection

EGR Control Circuit:

CIRCUIT DESCRIPTION
The EGR solenoids get battery power whenever the ignition is turned "ON", and become energized when the PCM completes the circuit to ground. Each solenoid has its own dedicated ground circuit through the PCM so that solenoids can be operated individually.

EGR Valve Check Procedure (Chart C-7):

TEST DESCRIPTION (numbers below refer to circled numbers on diagnostic chart)
1. You should be able to discern a change in engine speed as each solenoid is cycled "ON" and "OFF" again. The #3 solenoid may cause the engine to stall when cycled "ON" with the engine idling.
2. If the test light "lites up" the PCM and wiring are OK.

NOTE: EGR solenoids can be cycled "ON" and "OFF" manually by using the following supplemental procedure.

1. Instead of using a "SCAN" tool, start engine and disconnect EGR solenoid harness connector.
2. With engine idling, connect fused battery power (12 volts) to terminal "D" of solenoid valve assembly.
3. Ground terminal "C" of solenoid valve assembly.

^ Engine should stumble &/or die. If not check EGR passages for restriction. If passages are OK, replace EGR valve.

4. Ground terminal "B" of solenoid valve assembly.

^ You should notice a change in engine speed. If not, check EGR passages for restriction. If passages are OK, replace EGR valve.