Cooling Fan Always on (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. |
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.
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 (Except Opel Gt)
| • | Testing for Intermittent Conditions and Poor Connections |
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
| • | Scan Tool Data Definitions |
| • | Scan Tool Output Controls |
Circuit/system Verification
- If DTCs P0480, P0691, or P0692 are set, perform that diagnostic first.
- Ignition ON, verify with a scan tool that the ECM is not commanding fan activation.
- Ignition ON, observe that the fan is not activated.
Repair Instructions
Perform the Cooling Fan and Shroud Replacement after completing the diagnostic procedure.
Repair Verification
- Ignition ON, verify with a scan tool that the ECM is not commanding fan activation.
- Ignition ON, observe that the fan is not activated.
