Pcm Power Relay
- Check VPWR Circuit Resistance - Disconnect Idle Air Control (IAC) valve 2-pin harness connector. Disconnect scan tool from DLC. Disconnect PCM power relay (located in battery junction box). Measure resistance of VPWR circuit between IAC valve harness connector (White/Red wire) and PCM Power Relay connector (Red wire). See appropriate WIRING DIAGRAM under ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS. If resistance reading is less than 5 ohms, reconnect IAC valve harness connector and go to next step. If resistance reading is 5 ohms or more, repair open in VPWR circuit between PCM power relay connector (Red wire) and IAC valve (White/Red wire). After repair, restore vehicle to original condition and rerun QUICK TEST under SELF-DIAGNOSTIC SYSTEM.
- Check B+ & IGN START/RUN Voltage To PCM Power Relay - Measure B+ circuit (Red/Light Green wire) voltage at PCM power relay connector. Turn ignition on, engine off. Measure IGN START/RUN circuit (White/Violet wire) voltage at PCM Power Relay connector. If both voltages are more than 10.5 volts, go to next step. If both voltages are 10.5 volts or less, repair open in B+ (Red/Light Green wire) or IGN START/RUN (White/Violet wire) circuit. Verify condition of PCN diode. After repair, restore vehicle to original condition and rerun QUICK TEST under SELF-DIAGNOSTIC SYSTEM.
- Check Ground Circuit To Power Relay - Measure voltage between B+ circuit (Red/Light Green wire) and ground circuit (Black wire) at PCM Power Relay connector. Turn ignition off. If voltage reading was more than 10.5 volts, replace PCM power relay. After repair, restore vehicle to original condition and rerun QUICK TEST under SELF-DIAGNOSTIC SYSTEM. If voltage reading was 10.5 volts or less, repair open in ground circuit. After repair, restore vehicle to original condition and rerun QUICK TEST under SELF-DIAGNOSTIC SYSTEM.