P0482

DTC P0480, P0481, or P0482 (L61, 2.2L/LE5, 2.4L)

Circuit Description
The cooling fan has 2 windings in the motor, one winding is for low speed and the other winding is for high speed. The engine control module (ECM) controls the low speed fan operation by grounding the cool fan 1 relay control circuit. When the cooling fan 1 relay is energized, voltage is delivered to the cooling fan low speed winding. The ECM controls the high speed fan operation by grounding the cool fan 2 relay control circuit. When the cooling fan 2 relay is energized, voltage is delivered to the cooling fan high speed winding. The ECM controls the cooling fan relays by grounding the cooling fan relay control circuit through an internal solid state device called a driver. Each driver has a fault line which is monitored by the ECM. When the ECM is commanding a component ON, the voltage potential of the control circuit should be low, near 0 volts. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. If the fault detection circuit senses a voltage other than what is expected, the DTC will set.

The ECM will monitor the control circuit for the following conditions:
^ A short to ground
^ A short to voltage
^ An open circuit
^ An open relay coil
^ An internally shorted or excessively low resistance relay coil.

When the ECM detects any of the above conditions, the DTC will set and the affected driver will be disabled.

DTC Descriptors
This diagnostic procedure supports the following DTCs:
^ P0480 is for the low speed cooling fan relay control circuit.
^ P0481 is for the high speed cooling fan relay control circuit.
^ P0482 Is for the cooling fan relay control circuit.

Conditions for Running the DTC
^ The ignition is ON.
^ The battery voltage is more than 9 volts.

Conditions for Setting the DTC
^ The ECM detects an open, a short to ground, or a short to voltage on the cooling fan relay control circuit.
^ The condition must be present for a minimum of 6 seconds.

Action Taken When the DTC Sets
^ The ECM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The ECM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

Conditions for Clearing the MIL/DTC
^ The ECM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using the scan tool.

Diagnostic Aids
^ If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections.
^ Review the Freeze Frame/Failure Records vehicle mileage since the diagnostic test last failed. This may help determine how often the condition that caused the DTC to be set occurs. Component Tests and General Diagnostics

Test Description

Step 1 - Step 12:

Step 13 - Step 16:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for an audible click when the cooling fan 1 relay operates.
3. Listen for an audible click when the cooling fan 2 relay operates.
4. This step tests for voltage at the coil side of the cooling fan 1 relay. The cool fan 1 fuse supplies power to the cooling fan 1 relay.
5. This step tests for voltage at the coil side of the cooling fan 2 relay. The cool fan 2 fuse supplies power to the cooling fan 1 relay.
6. This step verifies that the ECM is providing ground to the cooling fan relay.
7. This step tests if ground is constantly being applied to the cooling fan relay.