Code 32 - EGR System Failure (1987 Models): Notes

The 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 EGR valve closed, manifold vacuum will be greater than it was during normal EGR operation and this change will be relayed to ECM by the MAP sensor. If the change is not within the calibrated window, Code 32 will be set if the following conditions occurs:

• Vehicle speed is above 50 mph.
• Engine vacuum is between 8-13 in. Hg.
• No change in throttle position while test is being run.
  NOTE: Test numbers refer to test numbers on diagnostic chart.

1. Checks for solenoid stuck open.
2. Checks for solenoid always being energized.
3. Grounding test terminal should energize solenoid and vacuum should drop.
4. Negative backpressure valve should hold vacuum with engine off.
5. When engine is started, exhaust backpressure should cause vacuum to bleed off and valve to fully close.
6. The 4.3L engine should have at least 7 in. Hg vacuum at idle.