P0480
DTC P0480, P0691, or P0692 (2.0L)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 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/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
* The engine speed is more than 80 RPM.
* The system voltage is between 10-18 volts.
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
* Engine Cooling Schematics
* Cooling System Component Views
Connector End View Reference
* Cooling System Connector End Views
* Engine Control Module 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
* Scan Tool Data List
* Scan Tool Data Definitions
* Scan Tool Output Controls
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
* Cooling Fan and Shroud Replacement (LNF) Cooling Fan and Shroud Replacement (LE5)
* Refer To Programing and Relearning Programming and Relearning
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.