DTC P0480, P0691, or P0692 2.0L

Diagnostic Instructions

DTC Descriptors

DTC P0480: Cooling Fan Speed Output Circuit

DTC P0691: Cooling Fan Speed Output Circuit Low Voltage

DTC P0692: Cooling Fan Speed Output Circuit High Voltage

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Speed Control Circuit	P0691	P0480	P0692	P0480

Circuit/System Description

The engine cooling fan is a variable speed fan. The engine control module (ECM) controls the fan speed by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the engine cooling fan motor in relation to the pulse width modulated signal. The cooling fan speed can be adjusted from 10 percent to 90 percent duty cycle. 90-94 percent is considered high speed fan.

The ECM monitors the voltage on the cooling fan speed control circuit driver output. Voltage is near B+ when the driver is OFF, and near ground when the driver is ON. If the difference between the actual and expected voltage exceeds a calibrated value, a DTC will set.

Conditions for Running the DTC

Conditions for Setting the DTC

P0480

The ECM detects 0 voltage on the output during commanded transitions.

P0691

The ECM detects low voltage on the output while commanded OFF.

P0692

The ECM detects high voltage on the output while commanded ON.

Action Taken When the DTC Sets

DTC P0480, P0691, and P0692 are Type B DTCs.

Conditions for Clearing the DTC

DTC P0480, P0691, and P0692 are Type B DTCs.

Reference Information

Schematic Reference

Connector End View Reference

Description and Operation

Cooling Fan Description and Operation

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Circuit/System Verification

1. Ignition ON, verify with a scan tool that the ECM is not commanding fan activation.
2. Ignition ON, command the cooling fan speed from 10-90 percent with a scan tool. The fan speed should transition with the commanded states.

Circuit/System Testing

Important: The Circuit/System Verification must be performed first or misdiagnosis may result.

1. Ignition OFF, disconnect the cooling fan speed control module.
2. Ignition OFF, install a test lamp between the cooling fan speed control circuit terminal 4 and B+. The lamp should be OFF.

⇒	If the lamp is ON, test the cooling fan speed control circuit for a short to ground. If the circuit tests normal, replace the ECM.

3. Ignition ON, command the cooling fan speed from 10-90 percent with a scan tool. The brightness of the lamp should change with the commanded states.

⇒	If the lamp brightness does not change correctly, test the cooling fan speed control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

4. If the ECM and the control circuit test normal, replace the cooling fan assembly.

Repair Instructions

Repair Verification

1. Ignition ON, verify with a scan tool that the ECM is not commanding fan activation.
2. Ignition ON, command the cooling fan speed from 10-90 percent with a scan tool. The fan speed should transition with the commanded states.