Captiva

Cooling Fan Circuit Diagnosis - LNQ

The engine cooling fan system consists of 2 electric cooling fans. The engine control module (ECM) commands via a pulse width modulated (PWM) signal the cooling fan control module ON in either high speed, medium speed, or low speed, depending on cooling requirements. In low speed, the fans are turned ON at a reduced speed. In medium speed, the fans are turned ON at a higher reduced speed. In high speed, the fans are turned ON at full speed.

The cooling fan control module is supplied with B+ and ground. It contains 2 drivers that control the 2 cooling fans, depending on cooling requirements which were send by the PWM signal from the ECM.

Schematic Reference

Engine Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation : Diesel Engines → Petrol Engines

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, command the Cooling Fan ON and OFF with a scan tool. The cooling fans should run as commanded.
2. Command the appropriate G10 Cooling Fan Motor operation through low, medium, and high speed operations with the scan tool Cooling Fan control. The appropriate G10 Cooling Fan Motor will increases from low speed, to medium speed, and high speed, and back down to OFF.
3. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

1. Ignition OFF, disconnect the K22 Cooling Fan Control Module.
2. Test for less than 5 Ω between the ground circuit terminal 2 X1 and ground.

⇒	If not the specified value, test the ground circuit for an open/high resistance or a short to voltage.

3. Install a test lamp between the B+ circuit terminal 1 X1 and ground. Verify the test lamp is ON.

⇒	If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

4. Ignition OFF, reconnect all harness connectors. Ignition ON, command the Cooling Fans ON and OFF with a scan tool. The cooling fans should run as commanded.

⇒	If the appropriate G10 Cooling Fan Motor does not run, test the PWM signal circuit for an open/high resistance, a short to ground and a short to voltage.

5. Disconnect the harness connector X2 and X3 at the K22 Cooling Fan Control Module.
6. Install a test lamp between the terminals listed below:

•	Control circuit terminal 1 X2 and low reference circuit terminal 2 X2 at the K22 Cooling Fan Control Module.

•	Control circuit terminal 2 X3 and low reference circuit terminal 1 X3 at the K22 Cooling Fan Control Module.

7. Command the Cooling Fans ON and OFF with a scan tool. The test lamp should turn ON as commanded.

⇒	If the test lamp does not illuminate, test the appropriate control circuit and low reference circuit for an open/high resistance.

⇒	If the test lamp is always ON, test the appropriate control circuit and low reference circuit for a short to voltage or a short to ground.

⇒	If all circuit tests normal, test the appropriate G10 Cooling Fan Motor.

8. If all circuit tests normal, test or replace the K22 Cooling Fan Control Module or the K20 Engine Control Module.

Dynamic Test

1. Ignition OFF, disconnect the harness connector at the appropriate G10 Cooling Fan Motor.
2. Install a 20 A fused jumper wire between the control circuit terminal 1 and 12 V, install a 20 A fused jumper wire between the low reference circuit terminal 2 and ground at the G10L Cooling Fan Motor - Left.
3. Verify the G10L Cooling Fan Motor - Left is operating properly.

⇒	If the G10L Cooling Fan Motor - Left is not operating properly, replace the G10L Cooling Fan Motor - Left.

4. Install a 20 A fused jumper wire between the control circuit terminal 2 and 12 V, install a 20 A fused jumper wire between the low reference circuit terminal 1 and ground at the G10R Cooling Fan Motor - Right.
5. Verify the G10R Cooling Fan Motor - Right is operating properly.

⇒	If the G10R Cooling Fan Motor - Right is not operating properly, replace the G10R Cooling Fan Motor - Right.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.