P0481

P0481-COOLING FAN 2 CONTROL CIRCUIT

P0481-Cooling Fan 2 Control Circuit:

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
- (A16) Fused B+ circuits
- (N112) Radiator fan high relay control circuit open
- (N112) Radiator fan high relay control circuit shorted to ground
- Radiator fan high relay
- Front control module

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. RADIATOR FAN HIGH RELAY OPERATION

Ignition on, engine not running.
With a scan tool, select Radiator Cooling Fan Relay #2 Control State, to actuate the Radiator Fan High Relay.

Q: Is the Cooling Fan Relay operating?

YES: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 2




2. (A16) FUSED B+ CIRCUITS

Turn the ignition off.
Remove the Radiator High Fan Relay.
Using a 12-volt test light connected to ground, probe the (A16) Fused B+ circuits in the Relay connection.

Q: Does the test light illuminate brightly?

YES: Go To 4
NO: Go To 3

3. RADIATOR FAN HI/LO CONTROL RELAY SHORTED INTERNALLY

With the test light still at the (A16) Fused B+ circuit (Radiator High Fan Relay), remove the Radiator Fan HI/LO Control Relay.

Q: When the relay is removed, does the test light illuminate brightly?

YES: Replace the Radiator Fan HI/LO Control Relay. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test
NO: Repair the open or short to ground in the (A16) Fused B+ circuits. Inspect the related fuse and repair as necessary. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test




4. RADIATOR FAN HIGH RELAY CONTROL CIRCUIT

Turn the ignition on, engine not running.
With a scan tool, select Radiator Cooling Fan Relay #2 Control State and then Toggle, to actuate the Radiator Fan High Relay.
Using a 12-volt test light connected to battery voltage, probe the Radiator Fan High Relay Control circuit in the PDM.

Q: Does the test light illuminate and flash on and off?

YES: Replace the Radiator Fan High Relay. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test
NO: Go To 5




5. (N112) RADIATOR FAN HIGH RELAY CONTROL CIRCUIT OPEN

Remove the FCM from the PDM.
Measure the resistance of the (N112) Radiator Fan High Relay Control circuit from the Relay connection to the FCM PDM - 49 way connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 6
NO: Replace the PDM. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test




6. (N112) RADIATOR FAN HIGH RELAY CONTROL CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (N112) Radiator Fan High Control circuit at the Relay connection.

Q: Is the resistance below 100 ohms?

YES: Go To 7
NO: Replace the Front Control Module. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test

7. RADIATOR FAN HI/LO CONTROL RELAY SHORTED INTERNALLY

With the probe still at the (N112) Radiator Fan High Control circuit, remove the Radiator Fan HI/LO Control Relay.

Q: Is the resistance still below 100 ohms?

YES: Repair the open or short to ground in the (N112) Radiator Fan High Control circuit. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test
NO: Replace the Radiator Fan HI/LO Control Relay. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test