DTC 32

Code 32 Chart:

Code 32 Wiring Diagram:

CIRCUIT DESCRIPTION:

The Exhaust Gas Recirculation (EGR) valve is opened by ported manifold vacuum. In order to control and monitor EGR application an Electrtonic Vacuum Regulator Valve (EVRV) is used. The EVRV is composed of two devices:

1. EGR solenoid, normally closed (vacuum blocked).
2. EGR vacuum switch, normally open, (no current flow).

EGR vacuum control is accomplished by the Electronic Control Module (ECM) grounding CKT 435, which energizes the EGR solenoid. This is done thousands of times a second. By varing the length of "ON" time, as compared to "OFF" time, Pulse Width Modulation (PWM). The ECM controls the vacuum source to the EGR valve. The EGR is monitored by the ECM through the EGR vacuum switch. The EGR vacuum switch, a normally open electrical switch, has an orfice built in which restricts the vacuum signal. When sufficient vacuum reaches the EGR vacuum switch to close the electrical switch, there should also be sufficient vacuum to open the EGR valve.

Code 32 will set, if the vacuum switch closes at idle, or, if it does not close under load (less than WOT).

^ Coolant temperature greater than 42.5~C (108~F).
^ Code 33 or 34 not present.
^ Engine running.
^ LV8 reading on "Scan" tool less than 144 counts.
^ No vacuum to EGR (switch open).
^ All conditions above must be met for 9.6 seconds.

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.

1. "Scan" tool displays the condition of the EGR diagnostic switch in the "Diagnostic Mode". In park or neutral, the display should read "OFF" (open switch).

2. Under moderate engine load, the display will switch from "OFF" to "ON".

3. Checks the integrity of the 12 volt feed and ground circuits. If these cicuits check OK, the fault is elsewhere in the EVRV/EGR control circuit.

4. A test light connected between terminals "A" and "B" will check for continuity of wiring and check for proper ECM operation.

5. If "ON" was displayed at idle, disconnect the EVRV harness. If display remains "ON" the fault is either a short to ground in CKT 932 or the ECM.

6. If the EGR display switches from "ON" to "OFF" when the EVRV is disconnected, the fault is either in the EVRV/EGR solenoid, CKT 435 or the ECM. Probing at terminal "B" will further isolate the fault. If the test light is "ON", disconnect ECM A-B connector before checking CKT 435 for a short to ground since the short could be inside the ECM.

DIAGNOSTIC AIDS:

^ An intermittent may be caused by a poor connection, rubbed through wire insulation, or a wire broken inside the insulation.

Check For:

^ Poor connection or damaged harness. Inspect ECM harness connectors for backed out terminal "D9" for improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and damaged harness.

^ Intermittent test. If connections and harness check OK, "Scan" EVRV switch, while moving related connectors and wiring harness. If the failure is induced, the "EVRV Switch" display will change. This may help to isolate the location of the malfunction.