DTC 32

DTC 32 Exhaust Gas Recirculation (EGR) Valve Diagnosis:

DTC 32 Exhaust Gas Recirculation (EGR):

Exhaust Gas Recirculation (EGR) Circuit:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) operates the linear Exhaust Gas Recirculation (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.
The Linear EGR valve is pulse width modulated by the PCM for the precise metering of the exhaust gas to the combustion chamber. Actual EGR pintle position is monitored by way of a pintle position sensor located on top of the valve. The pintle position sensor provides a varying feedback voltage so the PCM can compare actual pintle position to desired pintle position.

DIAGNOSTIC TROUBLE CODE (DTC) 32 WILL SET WHEN
DTC 32 is designed to diagnose the entire system, including the valve and pintle position sensor. To accomplish this, two separate diagnostic tests are utilized.

For "Test A", the PCM monitors EGR effectiveness by de-energizing the EGR control, thereby, shutting "OFF" the EGR valve. With the EGR valve closed, and the Heated Oxygen Sensor (HO2S) fluctuating normally, the 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.

For "Test B", the PCM will compare the difference between desired pintle position and the actual pintle position. If there is more than a 20% difference between them, a DTC 32 will 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%.
^ Manifold Absolute Pressure (MAP) above 60 kPa (17.7" of Hg) or less than 15 kPa (4.5" of Hg)

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
Numbers below refer to circled numbers on the diagnostic chart.

1. This test checks status of EGR pintle.
2. This test checks for correct operation of linear EGR valve.
3. This test checks control circuits.
4. This test checks power feed to EGR valve connector.
5. This test checks EGR control circuit connections and PCM.
6. This test checks pintle position signal circuit and PCM.
7. This test checks ground circuit for pintle position sensor and PCM.
8. This test checks for a ground in the EGR control circuit.
9. This test checks sensor ground and 5.0 Volt reference circuit and PCM.
10. This test checks sensor signal and circuit.
11. This test checks control module connections, pintle position signal circuit, EGR valve connections, EGR Valve, and Control Module.

DIAGNOSTIC AIDS
Before replacing PCM, use an ohmmeter and check the resistance of each PCM controlled relay and solenoid coil.