P0480

P0480-COOLING FAN 1 CONTROL CIRCUIT

For a complete wiring diagram, refer to the Wiring Information

Theory of Operation

The Powertrain Control Module (PCM) sends a Pulse-Width Modulated (PWM) signal to the Radiator Fan Module to control speed and a ground signal to the Radiator Fan Relay to control on/off operation.

- When Monitored:
With the ignition on. Battery voltage greater than 10 volts.

- Set Condition:
A short circuit to voltage is detected in (K173) Radiator Fan PWM Control circuit. One Trip Fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

Diagnostic Test

1. ACTIVE DTC
1. Turn the ignition on.
2. With the scan tool, read DTCs.

Does the scan tool display this DTC as active?

Yes

Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test.

2. CHECK THE (A957) RADIATOR FAN MODULE POWER CIRCUIT FOR OPEN/HIGH RESISTANCE
1. Turn the ignition on, engine not running.
2. Using a 12-Volt test light connected to battery ground, probe the (A957) Radiator Fan Module power circuit at the Fan Module.
3. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 3

No

- Repair the open in the (A957) Radiator Fan Module power circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

3. CHECK THE (Z903) RADIATOR FAN MODULE GROUND CIRCUIT FOR OPEN/HIGH RESISTANCE
1. Turn the ignition on, engine not running.
2. Using a 12-Volt test light connected to battery positive, probe the (Z903) Radiator Fan Module ground circuit at the Fan Module.
3. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 4

No

- Repair the open in the (Z903) Radiator Fan Module ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

4. RADIATOR FAN MODULE
1. Connect a jumper between ground and the (K173) Radiator Fan PWM Control circuit at the Radiator Fan Module harness connector.
2. Turn the ignition on.
3. With the scan tool, read DTC's.

Did DTC P0691 set?

Yes

- Replace the Radiator Fan Module.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

- Go To 5

5. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the relay and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Verify that there is good pin to terminal contact at the relay and PCM harness connectors.
5. Perform any Technical Service Bulletins (TSBs) that may apply.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test.

No

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