For 1990-2009 cars

## DTC P0480 or P0481 2.2L

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0480: Cooling Fan Relay 1 Control Circuit
DTC P0481: Cooling Fan Relay 2 Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Low Speed Cooling Fan Relay Control Circuit | P0480 | P0480 | P0480 | --
Low Speed Cooling Fan Relay Coil Voltage Supply Circuit | P0480 | P0480 | P0480 | --
High Speed Cooling Fan Relay Control Circuit | P0481 | P0481 | P0481 | --
High Speed Cooling Fan Relay Coil Voltage Supply Circuit | P0481 | P0481 | P0481 | --

### Circuit/System Description

The engine control module (ECM) grounds the low speed relay, which is relay 1, and the high speed relay, which is relay 2, control circuits through an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line that 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 ECM detects that the actual state of the control circuit does not match the expected state, a DTC will set.

### Conditions for Running the DTC

• | The ignition is ON.

• | The system voltage is between 9-18 volts.

### 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

DTCs P0480 and P0481 are Type B DTCs.

### Conditions for Clearing the DTC

DTCs P0480 and P0481 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

• | Master Electrical Component List

• | Component Connector End Views

#### Description and Operation

Cooling Fan Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

• | Electrical Center Identification Views

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, command Fan Relay 1 ON and OFF with a scan tool. The fan should turn ON low speed and OFF with each corresponding command.

⇒ | If the fan does not operate as specified, refer to Low Speed Fan Malfunction.

2. Command Fan Relay 2 ON and OFF with a scan tool. The fan should turn ON high speed and OFF with each corresponding command.

⇒ | If the fan does not operate as specified, refer to High Speed Fan Malfunction.

### Circuit/System Testing

#### Low Speed Fan Malfunction

1. Ignition OFF, disconnect the Cooling Fan Relay.
2. 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.

3. Ignition OFF, allow the ECM to completely power down.
4. Test for 70-110 ohms between terminals 85 and 86 of the Cooling Fan Relay.

⇒ | If not the specified range, replace the relay.

5. Connect a DMM, set to measure amperage in series with the relay coil and a 3A fused jumper wire between the B+ circuit terminal 85 and the control circuit terminal 86.
6. 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 140 mA with the relay commanded ON.

⇒ | If not the specified values, test the control circuit for a short to voltage, a short to ground, or an open/high resistance. If the circuit tests normal, replace the ECM.

7. If all circuits test normal, test or replace the Cooling Fan Relay.

#### High Speed Fan Malfunction

1. Ignition OFF, disconnect the Cooling Fan 2 Relay.
2. 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.

3. Ignition OFF, allow the ECM to completely power down.
4. Test for 70-110 ohms between terminals 85 and 86 of the Cooling Fan 2 Relay.

⇒ | If not the specified range, replace the relay.

5. Connect a DMM, set to measure amperage, in series with the relay coil and a 3A fused jumper wire between the B+ circuit terminal 85 and the control circuit terminal 86.
6. 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 140 mA with the relay commanded ON.
7. If all circuits test normal, test or replace the Cooling Fan 2 Relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Cooling Fan and Shroud Replacement

• | Cooling Fan and Shroud Replacement

• | Control Module References