Code 32 - EGR System Failure

EGR vacuum is regulated by an ECM-controlled solenoid. The ECM turns the EGR on and off (duty cycle) by grounding and ungrounding circuit No. 435. The duty cycle is calculated by the ECM based on coolant temperature, airflow and engine RPM. There should be no EGR when vehicle is in Park or Neutral, TPS input is less than a specified value or TPS is indicating Wide Open Throttle (WOT). With the ignition on and engine stopped, the EGR solenoid is de-energized. By grounding the diagnostic "test" terminal, the solenoid should energize.

Code 32 means that the EGR solenoid switch was closed during start-up or that the switch was not detected closed under the following conditions:

Coolant temperature is greater than 176°F (80°C).
EGR duty cycle command is greater than 48 percent.
TPS less than Wide Open Throttle (WOT), but not at idle.
Codes 21, 22, 33 and 34 not set.
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 above conditions are met, the "SERVICE ENGINE SOON" light remains on unless the switch changes state.

NOTE: Test numbers refer to test numbers on diagnostic chart.

This test will determine if the ECM set the code due to circuit No. 935 being grounded on start up. If the "Scan" tester does not indicate the switch is closed but the "SERVICE ENGINE SOON" light is on after start up, then this circuit should be checked carefully for an intermittent ground condition.
If the "Scan" tester indicates the switch is no longer closed after disconnecting it, be sure the switch is not closed due to heat. Ensure EGR valve is open prior to test.
This test will check for a possible open in circuit No. 935. The ECM supplies and monitors 9-12 volts on circuit No. 935. "Scan" tester should indicate switch being closed when circuit No. 935 is grounded.
By grounding the diagnostic "test" terminal, the EGR solenoid should close and allow vacuum to be applied. Vacuum should hold.
This test will determine if the electrical control part of the system is at fault, or if the connector or solenoid are at fault.
By plugging the EGR valve side and ungrounding the diagnostic "test" terminal, the solenoid valve should open and allow vacuum to bleed off through the vent.
With the engine not running and vacuum applied to the valve, the valve should move to the fully open position.
Due to engine using a negative backpressure valve, the valve should close when the engine is started.

Fig 1: Code 32 Schematic - EGR Sys Failure

Fig 2: Code 32 - EGR Sys Failure (1 of 3)

Fig 3: Code 32 - EGR Sys Failure (2 of 3)

Fig 4: Code 32 - EGR Sys Failure (3 of 3)