P0480

P0480-COOLING FAN 1 CONTROL CIRCUIT





For a complete wiring diagram refer to Diagrams/Electrical.

- When Monitored:

With the ignition on. Battery voltage greater than 10 volts.

- Set Condition:

An open or shorted 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.

Diagnostic Test

1. LOW SPEED RADIATOR FAN RELAY OPERATION

NOTE: If the P0480 is setting on a 5.7L engine, Refer to P1646-HYDRAULIC COOLING FAN CONTROL CIRCUIT LOW diagnostics.

Ignition on, engine not running.

With a scan tool, actuate the Low Speed Radiator Fan Relay.

Is the Cooling Fan Relay operating?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition

No

- Go To 2

2. FUSED B+ CIRCUITS





Turn the ignition off.

Remove the Low Speed Radiator Fan Relay.

Using a 12-volt test light connected to ground, probe the Fused B+ circuits.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the open or short to ground in the Fused B+ circuits. Inspect the related fuse and repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. LOW SPEED RADIATOR FAN RELAY RESISTANCE

Measure the resistance of the Low Speed Radiator Fan Relay Coil.

Is the resistance between 60 to 80 ohms?

Yes

- Go To 4

No

- Replace the Low Speed Radiator Fan Relay.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

4. RADIATOR FAN LOW RELAY CONTROL CIRCUIT OPEN





Disconnect the C3 FCM harness connector.

Measure the resistance of the Radiator Fan Low Relay Control circuit from the Relay to the C3 FCM harness connector.

Is the resistance below 5.0 ohms?

Yes

- Go To 5

No

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

5. RADIATOR FAN LOW RELAY CONTROL CIRCUIT SHORTED TO GROUND





Measure the resistance between ground and the Radiator Fan Low Relay Control circuit at the Relay connection.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the Radiator Fan Low Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. FRONT CONTROL MODULE

NOTE: Before continuing, check the FCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- perform BODY VERIFICATION TEST. Body Verification Test

No

- Replace Front Control Module.
- perform BODY VERIFICATION TEST. Body Verification Test