Diagnostic Aids
Perform this test when directed by QUICK TEST procedure. This CIRCUIT TEST is intended to diagnose:
- Wiring harness circuits (EGRC and PWR).
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color | ||
|---|---|---|---|---|---|
| EGRC | 102 | 33 | Gray | ||
| PWR | n/a | n/a | White/Red | ||
|
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1) Check PCM Output Signal Turn ignition off. Connect scan tester to DLC. Using scan tester, cycle solenoid on and off. If solenoid cycles, go to step 5). If solenoid does not cycle, go to next step.
2) Check Power To EGRC Solenoid Turn ignition off. Disconnect EGRC solenoid wiring harness connector. Turn ignition on. Measure voltage between harness connector PWR terminal and ground. If voltage is less than 10 volts, repair PWR circuit to EGRC solenoid. If voltage is at least 10 volts, go to next step.
3) Check EGRC Solenoid Turn ignition off. Check vacuum hoses for damage or loose fit. Repair as necessary. With connector removed, apply 12 volts to EGRC solenoid PWR terminal. Connect solenoid EGRC terminal to ground. Apply light air pressure to port "A" and verify pressure is released through port "B". See Fig 2 . If airflow is correct, go to next step. If airflow is not correct, replace solenoid.
4) Check EGRC Circuit Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Leave EGRC wiring harness connector disconnected. Measure resistance between breakout box test pin No. 33 and EGRC terminal of EGRC solenoid harness connector. Resistance should be 5 ohms or less. Check for continuity between breakout box test pin No. 33 and ground. Resistance should be 10,000 ohms or more. If resistance is as specified, replace PCM. If resistance is not as specified, repair circuit between PCM and EGRC solenoid.
5) Check EGR Valve Disconnect vacuum hose from EGR valve. Using pump, apply vacuum to EGR valve. If EGR valve diaphragm lifts, go to CIRCUIT TEST EGRT. If EGR valve diaphragm does not lift, replace EGR valve.