For 1990-2009 cars

## DTC P0480, P0481, P0691, P0692, P0693, or P0694 2.0L

### 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 and 3 Control Circuit
DTC P0691: Cooling Fan Relay 1 Control Circuit Low Voltage
DTC P0692: Cooling Fan Relay 1 Control Circuit High Voltage
DTC P0693: Cooling Fan Relay 2 Control Circuit Low Voltage
DTC P0694: Cooling Fan Relay 2 Control Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Cooling Fan Relay 1 Control Circuit for the Fan LO Relay | P0691 | P0480 | P0692 | --
FAN LO Relay Coil Voltage Supply Circuit | P0480 | P0480 | P0480 | --
Cooling Fan Relay 2 and 3 Control Circuit for the Fan CNTRL and FAN HI Relays | P0693 | P0481 | P0694 | --
CNTRL FAN and FAN HI Relays Coil Voltage Supply Circuit | P0481 | P0481 | P0481 | --

### Circuit/System Description

The engine control module (ECM) commands the fans ON in high speed or low speed. In low speed, the fans are configured in series. In high speed, the fans are configured in parallel.

In low speed operation, the ECM applies ground to the coil side of the low speed relay. Voltage is applied directly to the left cooling fan through the switch side of the low speed relay. The right fan is connected in series to the left fan through the de-energized series/parallel relay, which is the FAN CNTRL relay, so that both fans operate at low speed.

In high speed operation, the ECM applies a ground to the coil side of the low speed relay, the series/parallel relay, and the high speed relay. Voltage is applied directly to the right cooling fan through the switch side of the high speed relay. The left cooling fan obtains voltage through the low speed relay and ground through the series/parallel relay.

When the ECM is commanding a fan relay ON, the voltage of the control circuit should be low, near 0 volts. When the ECM is commanding a fan relay OFF, the voltage of the control circuit should be high, near battery voltage.

### Conditions for Running the DTC

• | The engine is running.

• | The system voltage is between 10-18 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

DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0480, P0481, P0691, P0692, P0693, and P0694 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Cooling Schematics

#### Connector End View Reference

• | Component Connector End Views

• | Electrical Center Identification 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

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References

### Circuit/System Verification

Verify cooling fan operation using the scan tool commands listed below:

• | Fan Relay 1 ON--Both fans run at low speed.

• | Fan Relays 2 and 3 ON--The right fan runs at high speed, the left fan is OFF.

• | Fan Relays 1, 2 and 3 ON--Both fans run at high speed.

### Circuit/System Testing

1. Ignition OFF, disconnect the 3 cooling fan relays listed below.

• | FAN LO relay

• | FAN CNTRL relay

• | FAN HI relay

2. Ignition ON, verify that a test lamp illuminates between ground and the appropriate ignition circuit terminal listed below:

• | Cool fan 1 relay, terminal 85

• | Cool fan 2 relay, terminal 85

• | Cool fan series/parallel relay, terminal 86

⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.

3. Verify that a test lamp does not illuminate between terminal 85 and terminal 86 of each relay.

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

4. Remove the test lamp.
5. Ignition ON, command the affected relay ON using a scan tool. Verify the affected scan tool FC Relay Control Ckt. Short Volts Test Status Parameter is OK.

• | For the FAN LO relay, use the scan tool Fan Relay 1 command.

• | For the FAN CNTRL and FAN HI relays, use the scan tool Relay 2 and 3 command.

⇒ | If not the specified value, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.

6. Install a 3A fused jumper wire between terminal 86 and terminal 85. Command the affected relay ON with a scan tool. Verify the scan tool Relay Control Ckt Short Volts Test Status Parameter is Fault.

⇒ | If not the specified value, test the control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

7. If all circuits and the ECM test normal, replace the affected relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Relay Replacement

• | Cooling Fan and Shroud Replacement

• | Control Module References for ECM replacement, setup, and programming