DTC 32

Note: If any other DTCs are stored, diagnose them first. If vehicle exhibits a rough or incorrect idle, repair idle complaint first.





DIAGNOSTIC CHART





WIRING DIAGRAM

INSPECTION PROCEDURE

Circuit Description:
The Engine Control Module (ECM) operates a solenoid to control the EGR valve. This solenoid is normally closed. By providing a ground path, the ECM energizes the solenoid which then allows vacuum to pass to the EGR valve.
The ECM monitors EGR effectiveness by de-energizing the EGR control solenoid thereby shutting "OFF" vacuum to the EGR valve diaphragm. With the EGR valve closed, fuel integrator counts will be greater than they were during normal EGR operation. If the change is not within the calibrated window, a DTC 32 will be set.

The ECM will check EGR operation when:
- Vehicle speed is above 50 mph.
- Engine vacuum is between 40 and 51 kPa.
- No change in throttle position while test is being run.

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. With the ignition "ON", engine stopped, the solenoid should not be energized and vacuum should not pass to the EGR valve. Grounding the diagnostic terminal will energize the solenoid and allow vacuum to pass to valve.
2. Checks for plugged EGR passages. If passages are plugged, the engine may have severe detonation on acceleration.
3. The vehicle must be driven during this test in order to produce sufficient engine load to operate the EGR. Lightly accelerating (approximately 1/4 throttle) will produce a large and stable enough reading to determine if the ECM is commanding the system "ON".

Diagnostic Aids:
- Before replacing ECM, use an ohmmeter and check the resistance of each ECM controlled relay and solenoid coil.
See ECM wiring diagram for coil terminal identification of solenoid(s) and relay(s) to be checked. Replace any solenoid where resistance measures less than 20 ohms.