Cooling Fan Inoperative

Cooling Fan Inoperative (LE5) (2.4L Without Hybrid)

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) commands the fans ON in high speed or low speed. In low speed, the fans are configured in series. In high speed, the fans are configured in parallel.

In low speed operation, the ECM applies ground to the coil side of fan relay. Voltage is applied directly to the left cooling fan through the switch side of low speed fan relay, which is FAN AUX relay 3. The right fan is connected in series to the left fan through the de-energized series/parallel relay, which is FAN CTRL relay, so that both fans operate at low speed.

In high speed operation, the ECM applies a ground to the coil side of low speed relay, series/parallel relay, and high speed fan relay, which is FAN MAIN relay. Voltage is applied directly to the right cooling fan through the switch side of fan main relay. The left cooling fan obtains voltage through low speed relay and ground through series/parallel relay.

When the ECM is commanding a fan relay ON, the voltage of the control circuit should be low, near 0 volts. When the ECM is commanding a fan relay OFF, the voltage of the control circuit should be high, near battery voltage.

Reference Information
Schematic Reference

Engine Cooling Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Cooling Fan Description and Operation (Except LAT) (Description and Operation)Cooling Fan Description and Operation (LAT) (Description and Operation)Cooling Fan Description and Operation (LCS) (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Circuit/System Verification

1. Verify that the following DTCs are not set: P0480 or P0481.

• If any of the DTCs are set, repair the DTC first.

2. Verify cooling fan operation using the scan tool commands listed below:

* Fan Relay 3 ON-Both fans run at low speed.
* Fan Relays 1 and 2 ON-The main fan runs at high speed, the AUX fan is OFF.
* Fan Relays 1, 2, and 3 ON-Both fans run at high speed.

Circuit/System Testing

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

1. Ignition OFF, disconnect series/parallel relay, which is FAN CTRL relay.
2. Ignition ON, activate the fan relay 1 with a scan tool. The fan should be OFF.

• If the fan is activated, test the left fan ground circuit terminal 1 for a short to ground.

3. Ignition OFF, disconnect the remaining fan relays.
4. Connect a 30A fused jumper between the normally-open switch contact terminals 30 and 87 at series/parallel relay connector in order to complete the left fan ground circuit. Leave this jumper in place for the remainder of this procedure.
5. One at a time, connect a 30A fused jumper between the positive terminal at the battery and the fan voltage supply circuit terminal 87 at each relay connection listed below and verify the appropriate fan activation:

* FAN AUX Relay
* Fan Main Relay

• If the appropriate fan does not activate, test the fan voltage supply circuit for a short to ground or open/high resistance. If the circuit tests normal, test the fan ground circuit for open/high resistance. If the circuits test normal, replace the fan.

6. Ignition ON, connect a 30A fused jumper between the relay switch voltage supply circuit terminal 30 and the fan voltage supply circuit terminal 87 at fan relay connections listed below and verify the appropriate fan activation:

* FAN AUX Relay
* Fan Main Relay

• If the appropriate fan does not activate, test the relay switch voltage supply circuit for a short to ground or high resistance.

7. If the circuits and fans test normal, replace the relay.

Repair Instructions

* Underhood Electrical Center or Junction Block Replacement (HP7) (Service and Repair)Underhood Electrical Center or Junction Block Replacement (HP5) (Service and Repair)
* Relay Replacement (Attached to Wire Harness) (Relay Replacement (Attached to Wire Harness))Relay Replacement (Within an Electrical Center) (Relay Replacement (Within an Electrical Center))
* Cooling Fan and Shroud Replacement (LAT) (Service and Repair)Cooling Fan and Shroud Replacement (HP5) (Service and Repair)Cooling Fan and Shroud Replacement (LE5, LZ4, LY7) (Service and Repair)

Repair Verification

1. Ignition ON, verify with a scan tool that the ECM is not commanding fan activation.
2. Ignition ON, observe that the fan is not activated.