DTC 32

Code 32 Chart:

Code 32 Wiring Diagram:

CIRCUIT DESCRIPTION:

The Exhaust Gas Recirculation (EGR) valve vacuum is controlled by an Electronic Control Module (ECM) controlled solenoid. 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 air flow sensor and engine rpm's. There should be "NO EGR" when in Park or Neutral, TPS input below a specified value or Throttle Position Sensor (TPS) indicating Wide Open Throttle (WOT). With the ignition "ON", engine stopped, the EGR solenoid is de-energized and by grounding the diagnostic terminal, the solenoid is energized.

NOTE: Because of all the possible color code combinations used on electrical wiring diagrams, always refer to ECM CONNECTOR IDENTIFICATION under ELECTRICAL AND ELECTRONIC WIRING DIAGRAMS for correct color code identification of circuit.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

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 48%.

^ TSP less than wide open throttle (WOT) but not at idle.

^ All conditions above must be met for about 4 minutes.

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


1. This test will determine if the ECM set the code due to CKT 935 being grounded on start up. If the "Scan" does not indicate the switch is closed but the customer complained of a "Service Engine Soon" light after start up then this circuit should be checked carefully for an intermittent grounded condition.

2. If the "Scan" indicates the switch is no longer closed after disconnecting it, be sure the switch is not closed due to heat. (EGR being "ON" prior to test.)

3. This test will check for a possible open in CKT 935. The ECM supplies 9-12 volts to CKT 935 and the "Scan" should indicate switch being closed when CKT 935 is grounded.

4. By grounding the diagnostic terminal, the EGR solenoid should close, and allow vacuum to be applied and the vacuum should hold.

5. This test will determine if the electrical control part of the system is at fault or if the connector or solenoid are at fault.

6. By plugging the EGR valve side and ungrounding the diagnostic terminal, the solenoid valve should open and allow vacuum to bleed off through the vent.

7. With the engine not running and vacuum applied to the valve, the valve should move to the fully open position.

8. Due to this engine using a negative back pressure valve, the valve should close when the engine is cranked over.