Circuit Test B - EEC-V Power Relay

NOTE: After each service or repair procedure has been completed, reconnect all components. Clear DTCs and repeat QUICK TEST procedures to ensure all EEC-V systems are working properly and DTCs are no longer present.

This circuit test is only intended to diagnose the following components and circuits:

Vehicle wiring harness circuits (VPWR, IGNITION START/RUN, B+ and Ground).
Power relay.
Powertrain Control Module (PCM).

Fig 1: Identifying Power Relay Circuits

1) Check VPWR Circuit Resistance

Turn ignition off. Disconnect Idle Air Control (IAC) solenoid and power relay wiring harness connectors. Disconnect scan tool (if applicable). Measure resistance of VPWR circuit between IAC solenoid wiring harness connector and power relay. See Fig 1. If resistance is less than 5 ohms, reconnect IAC solenoid and go to next step. If resistance is 5 ohms more, repair open in VPWR circuit between power relay and IAC solenoid.

2) Check Voltage To Power Relay

Ensure ignition is off and power relay is disconnected. Measure voltage between ground and B+ terminal at power relay wiring harness connector. Note voltage reading. Turn ignition on. Measure voltage between ground and IGN START/RUN terminal at power relay wiring harness connector. If any voltage reading is less than 10.5 volts, repair open circuit. If both voltage readings are more than 10.5 volts, replace power relay.

3) Check Ground Circuit To Power Relay

Measure voltage between ground terminal and B+ terminal at power relay wiring harness connector. If voltage is more than 10.5 volts, replace power relay. If voltage is 10.5 volts or less, repair open in ground circuit.