Diagnostic Aids
Perform this test when directed by another CIRCUIT TEST. This CIRCUIT TEST is intended to diagnose:
- Wiring harness circuit (VPWR, PWR and GND).
| Circuit | PCM Pin No. | (1) BOB Pin No. | Wire Color | ||
|---|---|---|---|---|---|
| GND | 4 | 44 | White/Green | ||
| VPWR | 38 | 37 | Red/Black | ||
| VPWR | 47 | 57 | Red/Black | ||
| VPWR | 109 | 6 | Red/Black | ||
|
|||||
1) Check VPWR To PCM Turn ignition off. Install Breakout Box(007-00033), leaving PCM disconnected. Turn ignition on. Measure voltage between breakout box test pins No. 6, 37 and 57 and ground. If voltage is 10 volts or more, circuit is okay and testing is complete. If voltage is less than 10 volts, go to next step.
2) Check VPWR Circuit Turn ignition off. Disconnect engine cont relay connector. Measure resistance between breakout box test pins No. 6, 37 and 57 and VPWR terminal of engine cont relay harness connector. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair VPWR circuit.
3) Check Power To Relay Leave engine cont relay disconnected. Turn ignition on. Measure voltage between PWR terminal at engine cont relay harness connector and ground. If voltage is greater than 10 volts, go to next step. If voltage is less than 10 volts, check 25-amp ENGINE CONT fuse. If fuse is okay, repair PWR circuit as necessary.
4) Check Ground At Relay Leave engine cont relay harness connector disconnected. Turn ignition on. Measure voltage between PWR and GND terminals at engine cont relay harness connector. If voltage is greater than 10 volts, go to next step. If voltage is less than 10 volts, repair GND circuit.
5) Check Engine Cont Relay Remove engine cont relay. Check for continuity between terminals No. 3 (PWR) and No. 4 (VPWR). Apply battery voltage between terminals No. 1 (PWR) and No. 2 (GND). See Fig 2 . Again, check for continuity between terminals No. 3 and 4. Continuity should be present when battery voltage is applied and not present when battery voltage is removed. If continuity is as specified, go to next step. If continuity is not as specified, replace engine cont relay.
6) Check Ground At PCM Ensure ignition is off and PCM is disconnected from breakout box. Measure resistance between breakout box test pin No. 44 and ground. If resistance is less than 5 ohms, replace PCM. If resistance is 5 ohms or more, repair GND circuit.