P0480

Diagnostic Chart:

Wiring Diagram:

Circuit Description

The cooling fan motor is controlled by the Powertrain Control Module (PCM) through the cooling fan relay. The PCM monitors coolant temperatures through the Engine Coolant Temperature (ECT) sensor. By monitoring the ECT sensor the PCM can calculate when to turn the cooling fan motor ON and OFF. When engine coolant temperatures reach above 97.5°C (208°F) the PCM will provide a ground path for the cooling fan relay which will turn ON the cooling fan motor. When engine coolant temperatures drop below 92.5°C (199°F) the PCM will remove the ground for the cooling fan relay and the cooling fan motor will be turned OFF.

Conditions for Setting the DTC

^ Output voltage check with the cooling fan motor ON.

^ Condition present for 5 seconds.

Action Taken When the DTC Sets

^ The Malfunction Indicator Lamp (MIL) will illuminate after two consecutive ignition cycles in which the diagnostic runs with the fault active.

^ The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame buffer.

Conditions for Clearing the MIL/DIC

^ The MIL will turn OFF after three consecutively passing cycles without a fault present.

^ A History DTC will clear after 40 consecutive warm-up cycles without a fault.

^ DTCs can be cleared by using a scan tool or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for any of the following conditions:

^ A poor connection at the PCM. Inspect the harness connectors for backed out terminal, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal to wire connection.

^ If the owner complained of an overheating problem, it must be determined if the complaint was due to an actual boil over, or the warning indicator light, or temperature gauge indicated overheating.

^ If the gauge, or light, indicates overheating, but no boil over is detected, the gauge or light circuit should be checked. The gauge accuracy can also be checked by comparing the coolant sensor reading using a scan tool with the gauge reading.

^ If the engine is actually overheating, and the gauge indicates overheating, but the cooling fan is not coming ON, the Engine Coolant Temperature (ECT) sensor has probably shifted out of calibration and should be replaced. Refer to DTC P0117 for Temperature vs. Resistance chart. P0117

^ If the engine is overheating, and the cooling fan is ON, the cooling system should be checked. Refer to Cooling and Radiator.

^ A blown fuse(s) could cause the malfunction.

If a DTC P0480 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

If any wiring repairs need to be made, Refer to Repair Procedures in Electrical Diagrams.

Test Description

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. When coolant temperatures reach above the specified value the cooling fan motor should turn ON.

3. Cooling fan motor should turn OFF when engine coolant temperatures drop below the specified value.

8. Checks the operation of the PCM and its circuitry.

11. Checks the operation of the cooling fan motor.