Cooling Fan Inoperative

Cooling Fan Inoperative (2.2L)

Diagnostic Instructions

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

Circuit/System Description

The engine control module (ECM) grounds the low speed relay, which is relay 1, and the high speed relay, which is relay 2, control circuits through an internal solid state device called a driver. The primary function of the driver is to supply the ground for the component being controlled. Each driver has a fault line that is monitored by the ECM. When the ECM is commanding a component ON, the voltage potential of the control circuit should be low, near 0 volt. When the ECM is commanding the control circuit to a component OFF, the voltage potential of the circuit should be high, near battery voltage. If the ECM detects that the actual state of the control circuit does not match the expected state, a DTC will set.

Reference Information
Schematic Reference

Engine Cooling Schematics (Electrical Diagrams)
Connector End View Reference

* Master Electrical Component List (Component Locations)
* Component Connector End Views (Connector Views)

Description and Operation

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

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
* Electrical Center Identification Views (Application and ID)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (Diagnostic Trouble Code Descriptions)
Scan Tool Reference

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

Circuit/System Verification

1. If DTCs P0480 or P0481 are set, then perform those diagnostics first.
2. Ignition ON, command each relay ON and OFF with a scan tool. Observe to verify that the fan turns ON and OFF with each command.

Circuit/System Testing

Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the affected Relay.
2. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground.

3. Disconnect the harness connector at the cooling fan.
4. Test for less than 1.0 ohm between the cooling fan ground circuit terminal 3 and ground.

• If not the specified range, test the ground circuit for an open/high resistance.

5. Connect the harness connector at the cooling fan.
6. Connect a 30A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the cooling fan is activated.

• If the cooling fan does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the cooling fan.

7. If all circuits test normal, test or replace the Relay.

Repair Instructions

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

* Cooling Fan and Shroud Replacement (Service and Repair)
* Cooling Fan and Shroud Replacement (Service and Repair)
* Control Module References (Programming and Relearning)

Repair Verification

Ignition ON, command each relay ON and OFF with a scan tool. Observe to verify that each fan turns ON and OFF with each command.