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) Cooling fan no.2 relay control circuit open
- (N112) Cooling fan no.2 relay control circuit shorted to ground
- High speed radiator fan relay
- Front control module

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test

1. HIGH SPEED RADIATOR FAN RELAY OPERATION

Ignition on, engine not running.
With a scan tool, actuate the High Speed Radiator Fan Relay.

Q: Is the Cooling Fan Relay operating?

YES: Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Component Tests and General Diagnostics
Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test
NO: Go To 2




2. (A16) 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 (A16) Fused B+ circuits in the Relay connection.

Q: Is the voltage above 11.0 volts?

YES: Go To 3
NO: Repair the open or short to ground in the (A16) Fused B+ circuits. Inspect the related fuse and repair as necessary. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

3. HIGH SPEED RADIATOR FAN RELAY RESISTANCE

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

Q: Is the resistance between 60 to 80 ohms?

YES: Go To 4
NO: Replace the Relay. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




4. (N112) COOLING FAN NO.2 CONTROL CIRCUIT OPEN

Disconnect the FCM 49 way harness connector.
Measure the resistance of the (N112) Cooling Fan No.2 Relay Control circuit from the Relay connection to the C3 FCM harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 5
NO: Repair the open in the (N112) Cooling Fan No.2 Relay Control circuit. Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test




5. (N112) COOLING FAN NO.2 CONTROL CIRCUIT SHORTED TO GROUND

Measure the resistance between ground and the (N112) Cooling Fan No.2 Relay Control circuit at the Relay connection.

Q: Is the resistance below 100 ohms?

YES: Repair the short to ground in the (N112) Cooling Fan No.2 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.

Q: Were there any problems found?

YES: Repair as necessary. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test
NO: Replace the Front Control Module. Perform BODY VERIFICATION TEST VER - 1. Body Verification Test