DTC 32

CIRCUIT DESCRIPTION
Code 32 means that the EGR diagnostic switch was closed during start-up, or that the switch was not detected closed under the following conditions:
^ Coolant temperature greater than 80°C (176°F).
^ EGR duty cycle commanded by the ECM is greater than 55%.
^ Throttle Position Sensor (TPS) less than half throttle, but not at idle.
^ All conditions above must be met for 5 seconds.

If the switch is detected closed during start-up, or, if the switch is detected open when the above conditions are met, the "Check Engine" light will remain "ON" unless the switch changes state.

The EGR vacuum control uses an Engine Control Module (ECM) controlled EGR valve. The valve is normally closed and the vacuum source is a ported signal. The ECM will turn the EGR "ON" and "OFF" (Duty Cycle) by grounding CKT 435. The duty cycle is calculated by the ECM based on information from the coolant and mass airflow sensor and engine RPM. The duty cycle should be 0% (no EGR) when in Park or Neutral, TPS input below a specified value or TPS indicating WOT.

With the ignition "ON", engine stopped, the EGR solenoid is de-energized unless the diagnostic terminal is grounded.

CHART TEST DESCRIPTION
1. If the first step caused code 32 to set, then the ECM has recognized a closed vacuum switch on start-up. This test will determine whether the EGR control valve is the cause or if the wiring or the ECM is the cause.

2. With the ignition on, the solenoid should not be energized and vacuum should not pass to the EGR valve.

3. To this point the EGR solenoid and valve are OK and the following check will check the diagnostic vacuum switch portion of the system.

4. The diagnostic switch should close at about 2" of vacuum. With vacuum applied, the switch should close and resistance go to near zero Ohms.