DTC P0480: Cooling Fan Relay No. 1 Circuit Low Input
- Perform basic diagnostic procedure. See BASIC DIAGNOSTIC PROCEDURE . Turn ignition off. Connect test mode connector. See Figure and Figure
. Turn ignition on. Using scan tool, command cooling fan relay on and off. Using a DVOM connected to ground, backprobe ECM connector B134 (35-pin connector) terminal No. 3 while commanding cooling fan relay on and off. See Figure. If voltage does not change between zero and 10 volts while commanding cooling fan relay on and off, go to next step. If voltage does change between zero and 10 volts while commanding cooling fan relay on and off, repair poor terminal contact at ECM connector.
- Turn ignition off. Disconnect ECM connector B134 (35-pin connector). Using an ohmmeter connected to ground, measure resistance at ECM connector B134 (35-pin connector) terminal No. 3. If resistance is less than 10 ohms, locate and repair short to ground in radiator fan relay No. 1 control circuit. See WIRING DIAGRAMS article. If resistance is not less than 10 ohms, go to next step.
- Turn ignition off. Remove main fan relay from fuse and relay holder. Turn ignition on. Measure voltage between ground and main fan relay cavity No. 5 (No. 28 on Forester, Impreza and Outback Sport) of fuse and relay holder. See Fig 1. If voltage is more than 10 volts, go to next step. If voltage is not more than 10 volts, locate and repair open circuit in wiring between ignition switch and fuse and relay holder.
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- With main fan relay removed, measure resistance between relay terminals No. 5 and No. 6. See Fig 2. If resistance is not between 87 and 107 ohms, replace main fan relay. If resistance is between 87 and 107 ohms, go to next step.
- Measure resistance of harness between ECM connector B134 (35-pin connector) terminal No. 3 and main fan relay cavity No. 6 (No. 27 on Forester, Impreza and Outback Sport) of fuse and relay holder. If resistance is less than one ohm, go to next step. If resistance is not less than one ohm, locate and repair open circuit in wiring and check for poor terminal contact in connectors between ECM and fuse and relay holder.
- Check for poor terminal contact in connectors between ECM and fuse and relay holder. If connectors are not okay, repair poor contact in connector. If connectors are okay, contact authorized Subaru dealership. Clear memory and perform verification procedure. See CLEARING DIAGNOSTIC TROUBLE CODES and VERIFICATION PROCEDURE
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