Code 32, EGR System Error - 3.1L: Notes
EGR vacuum is regulated by an ECM-controlled, normally closed solenoid. ECM will turn EGR on and off (duty cycle) by grounding and ungrounding solenoid drive circuit. Duty cycle is calculated by ECM based on coolant temperature, airflow and engine RPM. ECM will check EGR operation when vehicle speed is greater than 50 MPH, MAP is within calibrated range, throttle angle is 8-30 percent and throttle angle is constant. With ignition on and engine stopped, EGR solenoid is de-energized. Grounding ALDL test terminal should energize solenoid, allowing vacuum to pass through to EGR valve.
NOTE:
Test numbers refer to numbers on diagnostic chart.
- To check for plugged intake passage, turn ignition off. Remove EGR valve from intake. Plug exhaust side passage with a suitable stopper. With intake side open, attempt to start engine. If engine runs at a very high idle (up to 3000 RPM is possible) or starts and stalls, EGR intake passage is not plugged. If engine starts and idles normally, intake passage is plugged. To check for plugged exhaust passage, with EGR valve still removed, plug intake passage with a suitable stopper. Start engine. If no exhaust gas is present, passage is plugged.
- By grounding ALDL test terminal "B", EGR solenoid should energize, allowing vacuum to pass through solenoid. Vacuum may slowly bleed off. What is important is that vacuum passes through solenoid.
- When the ALDL test terminal "B" is ungrounded, vacuum should bleed off through a vent in the solenoid valve. What is important is that vacuum no longer exists on EGR side of solenoid.
- This test will determine if the electrical control part of the system is at fault or if the connector or solenoid valve is at fault.
- The remaining test checks the ability of the EGR valve to interact with exhaust system. This is a negative backpressure EGR valve which should hold vacuum with engine off.
- When engine is started, vacuum should vent and EGR valve should seat.