Test VPWR - Vehicle Power

Fig 1: Identifying Power Relay Circuit

Fig 2: Power Relay Connector Terminals ID

NOTE: 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 PIN IDENTIFICATION

Circuit	Breakout Box Pin No.	PCM Pin	Wire Color
GND	46	3D	Black/Blue
GND	49	3C	Black/Red
GND	20	3B	Black
GND	40 & 60	3A	Black
VPWR	37 & 57	1B	Red/Black

1) Check Circuit Integrity Visually check all wiring, connectors and components for evidence of damage, shorting or looseness. If fault is found, repair as necessary. If no fault is found, check battery voltage and charge condition. Service as necessary, and go to next step.

2) Check VPWR To PCM Turn ignition off. Install breakout box, leaving PCM disconnected. Turn ignition on. Measure voltage at VPWR test pin at breakout box. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, go to step 4).

3) Check PCM Grounds Turn ignition off. With breakout box installed and PCM disconnected, measure resistance between ground and each GND test pin at breakout box. If all resistances are less than 5 ohms, VPWR circuit is okay. Return to circuit test that sent you here. If one or more resistances is 5 ohms or more, repair open in GND wire(s).

4) Check VPWR Wire From Power Relay To PCM Ensure ignition is off, breakout box is installed and PCM is disconnected. Remove power relay. Relay is located inside engine compartment fuse/relay box. Measure resistance between VPWR test pin at breakout box and VPWR at power relay connector. If voltage is less than 5 ohms, go to next step. If voltage is 5 ohms or more, repair open VPWR wire.

5) Check Ground At Power Relay Turn ignition off. Remove power relay. Measure resistance between ground and GND terminal at power relay connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open power relay ground wire.

6) Check Voltage At Power Relay Turn ignition off. Measure voltage at BATT terminal at power relay connector. If voltage is more than 10 volts, go to next step. If voltage is 10 volts or less, check fuse to power relay. Fuse is located in engine compartment fuse/relay box. Replace fuse if blown. If fuse is okay, repair wire between fuse and power relay.

7) Check Power To Power Relay Turn ignition on. Measure voltage at PWR terminal at power relay connector. If voltage is more than 10 volts, replace power relay. If voltage is 10 volts or less, check 15-amp fuse to BATT wire. Fuse is located in instrument panel fuse block. Replace fuse if blown. If fuse is okay, repair PWR wire.