DTC 32

Code 32 - Exhaust Gas Recirculation (EGR) Circuit:

Wiring Diagram for Exhaust Gas Recirculation (EGR) Circuit:

CODE 32 - EXHAUST GAS RECIRCULATION (EGR) CIRCUIT

Circuit Description:


The Exhaust Gas Recirculation (EGR) valve vacuum is controlled by an Electronic Control Module (ECM) operated solenoid. The ECM will turn the EGR "ON" and "OFF" (Duty Cycle) by grounding CKT 901. The duty cycle is calculated by the ECM based on information from the coolant sensor, Manifold Absolute Pressure (MAP) sensor and engine rpm. There should be 0% (NO EGR) when in Park or Neutral, Throttle Position Sensor (TPS) input below a specified value or TPS indicating Wide Open Throttle (WOT).

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

Code 32 means that the EGR diagnostic 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 50%

^ Manifold pressure less than 25 kPa, (7" vacuum)

^ All conditions above must be met for about 8 seconds


Test Description: Numbers below refer to circled numbers on the diagnostic chart.

1. With the ignition "ON," the solenoid should not be energized and vacuum should not pass to the EGR valve.

2. To this point the EGR solenoid and valve are OK and the following checks will diagnose the diagnostic vacuum switch portion of the system.

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


Diagnostic Aids:


A "Scan" tool can also be used to check the diagnostic switch circuit. The "Scan" should display "ON" when vacuum is applied to the diagnostic switch. The switch should also be indicated as being closed whenever the ECM is commanding an EGR duty cycle of greater than 50%. EGR duty cycle can also be monitored by a "Scan" tool.