Cooling Fan Inoperative

Cooling Fan Inoperative (LAU)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Circuit/System Description

The engine control module (ECM) commands the cooling fan ON depending on the engine cooling requirements. The ECM controls the cooling fan speed by commanding the cooling fan control module. The cooling fan control module supplies the power and ground circuits for the cooling fan. The ECM sends a pulse width modulated (PWM) signal voltage to the cooling fan control module. The cooling fan control module interprets the signal and operates the cooling fan at the commanded speed.

Reference Information
Schematic Reference

Engine Cooling Schematics (Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Cooling Fan Description and Operation (LAU) (Cooling Fan Description and Operation)Cooling Fan Description and Operation (LF1) (Cooling Fan Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Ignition ON, verify that DTC P0480, P0691, or P0692, is not set.

• If a DTCs is set, refer to DTC P0480, P0691, or P0692 (without/LF1) (P0480).

Note: There is a slight delay before the cooling fan activates and reaches full speed.

2. Command the cooling fan ON with a scan tool. Verify that the cooling fan turns ON and operates at a high speed.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the K22 cooling fan control module.
2. Verify that a test lamp illuminates between the ground circuit terminal 2 and B+.

• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. If the cooling fan ground circuit/connections test normal, replace the K22 cooling fan control module.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Engine Coolant Fan Replacement (LF1) (Service and Repair)Engine Coolant Fan Replacement (LAU) (Service and Repair)
* Control Module References (Programming and Relearning)