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Pcm Power Relay

  1. Check VPWR Circuit Resistance

    Disconnect Idle Air Control (IAC) valve 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 terminal (White/Red wire) and PCM Power Relay battery junction box terminal (Red wire). See WIRING DIAGRAMS article. If resistance is less than 5.0 ohms, reconnect IAC valve and go to next step. If resistance reading is 5.0 ohms or more, repair open in VPWR circuit between PCM power relay (Red wire) and IAC valve (White/Red wire). After repair, restore vehicle to original condition and rerun QUICK TEST  under SELF-DIAGNOSTIC SYSTEM.

  2. Check B+ And IGN START/RUN Voltage To PCM Power Relay

    Measure B+ circuit (Red/Light Green wire) voltage at the PCM power relay connector. Turn ignition on, engine off. Measure IGN START/RUN circuit (White/Violet wire) voltage at PCM Power Relay battery junction box terminal. 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 circuit (White/Violet wire). After repair, restore vehicle to original condition and rerun QUICK TEST  under SELF-DIAGNOSTIC SYSTEM.

  3. Check Ground Circuit To Power Relay

    Measure voltage between B+ circuit (Red/Light Green wire) and ground circuit (Black wire) at PCM Power Relay battery junction box terminal. Turn ignition off. If voltage reading was more than 10.5 volts, replace PCM. 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.
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