Diagnostic Aids
Enter this test only when directed here by other circuit tests. To prevent replacement of good components, check for faults in following non-EEC components:
- Ignition switch.
- Alternator.
- Battery cables, ground straps and voltage regulator.
This test is only intended to diagnose following circuits: VPWR and GND.
CIRCUIT TEST B PIN IDENTIFICATION
| Circuit | Breakout Box Pin No. | PCM Pin No. | Wire Color |
|---|---|---|---|
| GND | 18 | C201-10 | Black |
| GND | 17 | C201-20 | Black |
| GND | 52 | C200-1 | Black/Lt. Green |
| GND | 52 | C200-2 | Black/Orange |
| GND | 54 | C200-15 | Black/Orange |
| KAPWR | 55 | C200-5 | Blue/Red |
| VPWR | 51 | C200-14 | Yellow/White |
This circuit test is only intended to diagnose the following components and circuits:
- Vehicle wiring harness circuits (VPWR and ground).
- Main power relay.
- 1) Check VPWR To PCM Turn ignition off. Install breakout box (leave PCM disconnected). Turn ignition on. Measure voltage at breakout box test pin(s) VPWR. If voltage is greater than 10.5 volts, go to next step. If voltage is less than 10.5 volts, go to step 3).
- 2) Check Grounds At PCM Leave ignition off. Install breakout box. (leave PCM disconnected). Measure resistance between ground and breakout box test pins GND. If resistance is less than 5 ohms, VPWR circuit is okay. Return to test that sent you here. If resistance is greater than 5 ohms, repair GND circuit in question.
- 3) Check VPWR Wire From Main Relay To PCM Turn ignition off. Install breakout box (leave PCM disconnected). Remove main power relay (located in fuse panel). Measure resistance between breakout box test pin VPWR and VPWR wire at main relay connector. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair VPWR wire.
- 4) Check Ground At Main Power Relay Turn ignition off. Remove main power relay (located in fuse panel). Measure resistance between ground and GND terminal at main power relay. If resistance is less than 5 ohms, go to next step. If resistance is greater than 5 ohms, repair GND circuit in question.
- 5) Check Battery Voltage At Main Power Relay Turn ignition off. Remove main power relay (located in fuse panel). Measure voltage at BATT terminal at main power relay connector. If voltage is 10.5 volts or greater, go to next step. If voltage is less than 10.5 volts, check 30-amp EGI INJ fuse. If fuse is not the problem, service BATT circuit.
- 6) Check PWR Circuit To Main Power Relay Turn ignition off. Remove main power relay (located in fuse panel). Turn ignition on. Measure voltage at PWR terminal at main power relay connector. If voltage is 10 volts or greater, replace main power relay. If voltage is less than 10 volts, check 10-amp ENGINE fuse. If fuse is not the problem, service PWR circuit.
- 10) Check Fuse Check ROOM fuse. If fuse is good, go to next step. If fuse is not good, replace ROOM fuse and retest vehicle. If ROOM fuse blows again, check circuit for short to ground. Refer to wiring diagrams as necessary to trace all circuits protected by ROOM fuse.
- 11) Check Voltage Input To PCM Install breakout box. Measure voltage between test pin KAPWR and test pin GND. If voltage is more than 10.5 volts, voltage input is good. Replace PCM. Rerun diagnostic test. If voltage is 10.5 volts or less, repair open in KAPWR circuit. Rerun diagnostic test.