P0481-COOLING FAN 2 CONTROL CIRCUIT
For a complete wiring diagram Refer to Section 8W.
- 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.
| Possible Causes |
| FUSED B+ CIRCUITS |
| RADIATOR FAN HIGH RELAY CONTROL CIRCUIT OPEN |
| RADIATOR FAN HIGH RELAY CONTROL CIRCUIT SHORTED TO GROUND |
| HIGH SPEED RADIATOR FAN RELAY |
| FRONT CONTROL MODULE |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1. HIGH SPEED RADIATOR FAN RELAY OPERATIONIgnition on, engine not running.
With a scan tool, actuate the High Speed Radiator Fan Relay.
Is the Cooling Fan Relay operating?
Yes
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 2
2. FUSED B+ CIRCUITS
Turn the ignition off.
Remove the High Speed Radiator Fan Relay.
Using a 12-volt test light connected to ground, probe the Fused B+ circuits in the Relay connection.
Is the voltage above 11.0 volts?
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. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3. HIGH SPEED RADIATOR FAN RELAY RESISTANCE
Measure the resistance of the High Speed Radiator Fan Relay Coil.
Is the resistance between 60 to 80 ohms?
Yes
- Go To 4
No
- Replace the Relay.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4. RADIATOR FAN HIGH CONTROL CIRCUIT OPEN
Disconnect the FCM 49 way harness connector.
Measure the resistance of the Radiator Fan High Relay Control circuit from the Relay connection 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 High Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
5. RADIATOR FAN HIGH RELAY CONTROL CIRCUIT SHORTED TO GROUND
Measure the resistance between ground and the Radiator Fan High Relay Control circuit at the Relay connection.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the Radiator Fan High Relay Control circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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 the BODY VERIFICATION TEST. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)
No
- Replace the Front Control Module per Service Information.
- Perform the BODY VERIFICATION TEST. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE)