Powertrain Controls - ECM/PCM

DTC 32 Chart:

Linear EGR Circuit:

CIRCUIT DESCRIPTION:
The PCM operates the linear EGR valve to control exhaust gas recirculation by providing a ground control that commands the pintle valve away from its seat allowing exhaust gas through the valve.

DTC 32 WILL SET WHEN:
The PCM monitors EGR effectiveness by de-energizing the EGR control, thereby shutting "OFF" the EGR valve. With the EGR valve closed, and HO2S fluctuating normally, fuel integrator counts will be greater than they were during normal EGR operation. If the change is not within the calibrated window, after failing the test twice a DTC 32 will be set.
The PCM will check EGR operation when:
^ Throttle position between 10% and 25% angle.
^ Steady throttle with no more then 2% change in throttle.
^ Above 32 mph "Closed Loop" operation.
^ Max short term fuel trim less then 6 counts for 3.2 seconds.
^ Desired EGR command greater then 40%.
^ MAP above 60 kPa or less than 15 kPa.

ACTION TAKEN (PCM WILL DEFAULT TO):
The PCM will turn "ON" the Malfunction Indicator Lamp (MIL).

DTC 32 WILL CLEAR WHEN:
Conditions for fault are no longer present and Tech 1 scan tool clear DTCs function is used or 50 ignition switch keycycles have passed with no further faults or ignition switch is turned "OFF" and ECM "B" fuse is removed for 10 seconds.

DTC CHART TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step checks the pintle's ability to be commanded to the desired position.
2. This step checks for voltage to the linear EGR valve to verify if the problem is in the ignition feed circuit.
3. This checks the PCM control circuit by jumpering across the CKT 435 and CKT 439 with a test light and grounding the diagnostic connector to command the EGR "ON."

DIAGNOSTIC AIDS:
Before replacing PCM, use an ohmmeter and check the resistance of each PCM controlled relay and solenoid coil.
With J 39200, check resistance of EGR pins:

A to E
(Vertical Connector) - 7.8 - 8.6 ohms
A to E
(Horizontal Connector) - 9.5 - 10.5 ohms
B to D - Above 3K
D to C - From 0.7 to 4.0K when slowly moving pintle valve inward