Throttle Body Fuel Injection System

Fig. 087 - Wiring Diagram for Chart C-7 EGR Check. VIN Z:

CHART C-7

EXHAUST GAS RECIRCULATION

4.3L ENGINE

FUEL INJECTION (TBI)

The Exhaust Gas Recirculation (EGR) valve is controlled by a normally open solenoid (allows vacuum to pass when energized). The ECM energizes the solenoid to turn the EGR on, and monitors EGR flow with the EGR temperature switch. Code The Exhaust Gas Recirculation (EGR) valve is controlled by a normally open solenoid (allows vacuum to pass when energized). The ECM energizes the solenoid to turn the EGR on, and monitors EGR flow with the EGR temperature switch. Code 32 will detect a faulty solenoid, temperature switch, or vacuum supply. Chart C-7 checks for plugged EGR passages, a sticking EGR valve, or a stuck open solenoid.
The ECM controls EGR based on the following inputs:
a. Engine Coolant - above 45°C (113°F)
b. Throttle Position Sensor - part throttle.
c. Manifold Absolute Pressure - mid-range.

Fig. 086 Chart C-7 EGR Check:

1. With the ignition "ON", engine stopped, the solenoid should not be energized and vacuum should not pass to the EGR valve.
2. Grounding the diagnostic terminal will energize the solenoid and allow vacuum to Grounding the diagnostic terminal will energize the solenoid and allow vacuum to pass to valve.
3. Checks for plugged EGR passages. If passages are plugged, the engine may have severe detonation on acceleration.