P0481

P0481-COOLING FAN 2 CONTROL CIRCUIT

For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The Powertrain Control Module (PCM) controls the Cooling Fan 2 (High Speed) Relay by grounding the High Rad Fan Relay Control circuit when it is determined that high speed fan operation is required.

- When Monitored:
With the ignition on. Battery voltage greater than 10 volts.

- Set Condition:
An open circuit is detected in the Radiator Fan Relay Control circuit. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC
1. Turn the ignition on.
2. Using the scan tool, actuate the Radiator Fan.
3. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. RADIATOR FAN RELAY
1. Remove the Radiator Fan Relay.
2. Turn the ignition on.
3. Using the scan tool, actuate the Radiator Fan.
4. Using a 12-Volt test light connected to 12 volts, probe the (K175) Radiator Fan Relay Control circuit at the relay (Fan Relay terminal 86).
5. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Replace the Radiator Fan Relay.

No

- Go To 3

3. CHECK THE (K175) RADIATOR FAN RELAY CONTROL CIRCUIT FOR AN OPEN CIRCUIT
1. Stop the Radiator Fan actuation.
2. Turn the ignition off.
3. Disconnect the PCM C1 harness connector.
4. Measure the resistance of the (K175) Radiator Fan Relay Control circuit between the Fan Relay (terminal 86) and the PCM C1 harness connector.

Is the resistance above 5 ohms?

Yes

- Repair the open in the (K175) Radiator Fan Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 4

4. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the relay and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Verify that there is good pin to terminal contact at the relay and PCM harness connectors.
5. Perform any Technical Service Bulletins (TSBs) that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Replace and program the Powertrain Control Module (PCM). .
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.