DTC P1491: Radiator Fan Control Relay Circuit: Testing

Turn ignition on with engine off. Using scan tool, actuate radiator fan relay. Check radiator fan operation. If radiator fan cycles on and off, go to next step. If radiator fan does not cycle on and off, go to step 4 .
Ensure ignition is still on and radiator fan control relay is still actuated. Wiggle wiring harness and connectors from radiator fan control relay to PCM while noting operation of radiator fan. Radiator fan relay is located behind right bumper fascia, below right headlight assembly. PCM is located on firewall in right rear corner of engine compartment. If radiator fan operation was not interrupted while wiggling wiring harness and connectors, go to next step. If radiator fan operation was interrupted while wiggling wiring harness and connectors, repair wiring harness as necessary where wiggling caused radiator fan operation to be interrupted.
Turn ignition off. Inspect wiring and connectors between radiator fan relay and PCM. If no problems exist, test is complete. If any problems exist, repair wiring or connectors as necessary.
Turn ignition off. Disconnect radiator fan relay connector. Measure resistance and Black wire at radiator fan relay connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Black wire.
Ensure ignition is off. Disconnect PCM connectors. PCM is located on firewall in right rear corner of engine compartment. Inspect connectors for damaged pins, corrosion and loose terminals. Repair connectors as necessary. If connectors are okay, measure resistance of Dark Blue/Pink wire between radiator fan relay connector and terminal No. 17 at PCM C2 connector. See Figure . If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Dark Blue/Pink wire.
Measure resistance between ground and terminal No. 17 (Dark Blue/Pink wire) at PCM C2 connector. See Figure . If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground in Dark Blue/Pink wire.
Reconnect radiator fan relay connector. Connect a jumper wire between ground and terminal No. 17 (Dark Blue/Pink wire) at PCM C2 connector and observe radiator fan operation. If radiator fan is on, go to next step. If radiator fan is off, replace radiator fan relay.
At this time, PCM is assumed to be defective. Replace PCM.