P0480

P0480-COOLING FAN 1 CONTROL CIRCUIT/OPEN





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the engine running, battery voltage greater than 10.4 volts, and the Radiator Fan Control Relay control active.

- Set Condition:
The PCM detects an open or shorted condition in the Radiator Fan Control Relay control circuit.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.Initial Inspection and Diagnostic Overview

Diagnostic Test

1. DTC IS ACTIVE
Turn the ignition on.
With the scan tool, Clear DTCs in the Powertrain Control Module (PCM).
With the scan tool, actuate the Radiator Cooling Fan PWM Control State.
With the scan tool, select View DTCs.
Is the status Active for this DTC?

Yes

- Go to 2

No

- REFER TO the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure.Checking For An Intermittent DTC

2. (K173) RAD FAN RELAY CONTROL CIRCUIT SHORTED TO GROUND




Turn the ignition off.
Disconnect the Radiator Fan Control Relay.
Disconnect the Powertrain Control Module (PCM) connector.
Measure the resistance between ground and the (K173) Rad Fan Relay Control circuit in the Radiator Fan Control Relay connector.
Is the resistance above 100 ohms?

Yes

- Go to 3

No

- Repair the (K173) Rad Fan Relay Control circuit for a short to ground.
- Perform the PCM Verification Test.Powertrain Verification Test

3. (K173) RAD FAN RELAY CONTROL CIRCUIT OPEN OR HIGH RESISTANCE




CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals, resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K173) Rad Fan Relay Control circuit between the Radiator Fan Control Relay connector and the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?

Yes

- Go to 4

No

- Repair the (K173) Rad Fan Relay Control circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test

4. (Z723) GROUND CIRCUIT OPEN OR HIGH RESISTANCE




Using a 12 volt test light connected to 12 volts, check the (Z723) Ground circuit in the Radiator Fan Control Relay connector.

NOTE: The test light should be illuminated and bright. Compare the brightness to that of a direct connection to the battery.

Is the test light illuminated and bright?

Yes

- Go to 5

No

- Repair the (Z723) Ground circuit for an open circuit or high resistance.
- Perform the PCM Verification Test.Powertrain Verification Test

5. RADIATOR FAN CONTROL RELAY




Connect the Powertrain Control Module (PCM) connector.
Turn the ignition on.
With the scan tool, actuate the Radiator Cooling Fan PWM Control State.
Using a 12 volt test light connected to ground, check the (K173) Rad Fan Relay Control circuit in the Radiator Fan Control Relay connector.

NOTE: The voltage supplied to the solenoid circuit during the actuation will be less than battery voltage. The test light should be illuminated, but not as bright as a direct connection to the battery.

Is the test light illuminated during the actuation?

Yes

- Replace the Radiator Fan Control Relay.
- Perform the PCM Verification Test.Powertrain Verification Test

No

- Go to 6

6. POWERTRAIN CONTROL MODULE (PCM)
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Radiator Fan Control Relay and the Powertrain Control Module (PCM).
Look for any chafed, pierced, pinched, or partially broken wires.
Look for broken, bent, pushed out or corroded terminals.
Search for any Technical Service Bulletins that may apply.
Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test.Powertrain Verification Test

No

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