P0480

DTC P0480 (2.2L or 2.4L)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptor
DTC P0480
- Cooling Fan Relay Control Circuit

Diagnostic Fault Information





Circuit/System Description

The engine cooling fan system consists of one cooling fan and one relay. The relay is powered by the battery positive voltage circuit and controlled by a switched ground from the engine control module (ECM).

During operation, the ECM supplies the ground path for the cooling fan relay, which is relay 1, through the cooling fan relay control circuit. This energizes the cooling fan relay coil, closes the relay contacts, and supplies battery positive voltage from the cooling fan fuse through the cooling fan motor supply voltage circuit to the cooling fan. The cooling fan motor is grounded through its own ground circuit.

Conditions for Running the DTC

* The engine is running.
* The system voltage is between 11-18 volts.
* The relay control circuit is transitioned from OFF to ON, or ON to OFF.

Conditions for Setting the DTC

* An improper voltage level has been detected on the cooling fan relay control circuit.
* The condition must be present for a minimum of 30 seconds.

Action Taken When the DTC Sets

DTC P0480 is a Type B DTC.

Conditions for Clearing the DTC

DTC P0480 is a Type B DTC.

Reference Information
Schematic Reference

Engine Cooling Schematics (Diagrams)
Connector End View Reference

* Component Connector End Views (Connector Views)
* Electrical Center Identification Views (Application and ID)

Description and Operation

Cooling Fan Description and Operation (Cooling Fan Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Programming and Relearning (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, command the relay ON and OFF with a scan tool. Feel or listen to verify that the relay turns ON and OFF with each command.

Circuit/System Testing

1. Ignition OFF, disconnect the cooling fan relay.
2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify that a test lamp illuminates between the B+ circuit terminal 85 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, test or replace the relay.

4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

5. Disconnect the harness connector at the cooling fan.
6. Test for less than 1.0 ohm between the cooling fan ground circuit terminal A and ground

• If greater than the specified range, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the cooling fan.
8. Connect a 30A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the cooling fan is activated.

• If the cooling fan does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the cooling fan.

9. Verify that a test lamp does not illuminate between the B+ circuit terminal 85 and the control circuit terminal 86.

• If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.

10. Ignition OFF, allow the ECM to completely power down.
11. Test for 70-110 ohms between terminals 85 and 86 of the cooling fan relay.

• If the resistance is not within the specified range, replace the relay.

12. Measure amperage with a DMM connected in series with the relay coil and a 3A fused jumper wire between the B+ circuit terminal 85 and the control circuit terminal 86.
13. Ignition ON, command the relay ON and OFF with a scan tool. The DMM should indicate less than 1 mA with the relay commanded OFF and approximately 170 mA with the relay commanded ON.

• If the DMM does not indicate the specified values, test the control circuit for an open or a short to voltage. If the circuit tests normal, replace the ECM.

14. If all circuits test normal, test or replace the cooling fan relay.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Cooling Fan and Shroud Replacement (LE8, LE9) (Service and Repair)Cooling Fan and Shroud Replacement (LNF) (Service and Repair)
* Engine Coolant Fan Shroud Replacement (Service and Repair)
* Engine Control Module Replacement (Service and Repair)