DTC 32

DTC 32 Linear Exhaust Gas Recirculation (EGR) System (Part 1 Of 2):

DTC 32 Linear Exhaust Gas Recirculation (EGR) System (Part 2 Of 2):

Linear Exhaust Gas Recirculation (EGR) System:

CIRCUIT DESCRIPTION
The linear EGR valve is pulse width modulated by the PCM for precise metering of the exhaust gas to the combustion chamber. Actual EGR pintle position is monitored by the 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.

DTC 32 WILL SET WHEN
DTC 32 was designed to diagnose the entire system, including the valve and pintle position sensor. To accomplish this, two separate diagnostic test 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 H02S 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. 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, 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 (17.8 Hg) or less then 15 kPa (4.5 Hg).

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

DTC 32 WILL CLEAR WHEN
Conditions for fault are no longer present and Tech 1 "Clear DTCs" function is used or 50 ignition switch keycycles have passed with no further faults or ignition switch is turned "OFF" and fuse #9 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 status of EGR pintle.
2. This step checks for correct operation of linear EGR valve.
3. This step checks linear EGR valve control circuits.
4. This step checks power feed to EGR valve connector.
5. This step checks EGR control circuit connections and PCM.
6. This step checks pintle position signal circuit and PCM.
7. This step checks ground circuit for pintle position sensor and PCM.
8. This step checks for a ground in EGR control circuit.
9. This step checks sensor ground and 5V reference circuit, and PCM.
10. This step checks sensor signal and circuit.
11. This step 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.