Code 32, EGR System Error (1 Of 3)
ECM operates a normally closed solenoid to regulate vacuum to EGR valve. When ECM provides a path to ground for the EGR solenoid winding, solenoid opens, allowing vacuum to pass through to EGR valve. ECM monitors EGR effectiveness by shutting off vacuum to EGR valve during a steady cruise above 50 MPH, and monitoring the change in MAP sensor vacuum signal. If vacuum signal change is not within a precalibrated window, Code 32 will be set.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Plugged Intake Passage - Shut off engine and remove EGR valve. Plug exhaust side port with a shop rag or suitable plug. Attempt to start engine. If engine runs at a very high idle (up to 3000 RPM is possible) or if engine starts and stalls, EGR intake passage is not plugged. If vehicle starts and idles normally, intake side passage is plugged. Plugged Exhaust Passage - With EGR valve removed, plug intake manifold side passage with a suitable plug. Start engine and listen for exhaust noise. If no exhaust gas escapes from open EGR port, exhaust passage is plugged.
- By grounding ALDL test terminal B, EGR solenoid should energize and allow vacuum to be applied to gauge. Vacuum at gauge may or may not slowly bleed off; however, what is important is that gauge is able to read amount of vacuum being applied.
- When ALDL test terminal is ungrounded, gauge vacuum should bleed off through a vent in the solenoid. Pump gauge vacuum may or may not bleed off but this does not indicate a problem.
- This test determines if electrical control part of system is at fault or if the connector or solenoid is at fault.
- EGR valves used with this engine are stamped with a P for positive backpressure or an N for negative backpressure. Proceed to the appropriate chart for the valve being tested.