Vauxhall Workshop Service and Repair Manuals

Cooling Fan Always On - 2H0, LDE, LDD, LLU or LUJ

Diagnostic Instructions

Diagnostic Fault Information

Circuit/System Description

The engine cooling fan system is composed of one fan, 3 relays, the engine control module (ECM), and the associated wiring. The fan assembly includes two resistors, which enable the fan to operate at 3 speeds.

Low Speed

In low speed operation, the ECM provides ground from ECM terminal 44 X1. The Cooling Fan Low Speed Relay activates and provides power to the cooling fan motor through cooling fan motor terminal 2 and the internal fan resistor.

Medium Speed

In medium speed operation, the ECM provides ground from ECM terminal 15 X1. The Cooling Fan Medium Speed 1 Relay activates and provides power to the cooling fan motor through cooling fan motor terminal 3 and the internal fan resistor.

High Speed

In high speed operation, the ECM provides ground to ECM terminals 15 X1 and 44 X1. As previously described, power is now provided to both cooling fan terminals 2 and 3. In addition, power and ground are now provided to the coil of the Cooling Fan High Speed Relay. The Cooling Fan High Speed Relay activates and provides power to the cooling fan motor through cooling fan terminal 4.

Reference Information

Schematic Reference

Connector End View Reference

Component Connector End Views

Description and Operation

Cooling System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Verify that DTCs P0480 or P0481 are not set.

⇒	If a DTC is set, refer to DTC P0480 or P0481 for further diagnosis.

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

Circuit/System Testing

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

1. Ignition OFF, disconnect the relays listed below:

•	KR20P Cooling Fan Medium Speed Relay

•	KR20C Cooling Fan Low Speed Relay

•	KR20D Cooling Fan High Speed Relay

2. Ignition ON, observe that the G10 Cooling Fan Motor is not activated.

⇒	If the G10 Cooling Fan Motor is activated, test the control circuits listed below for a short to voltage. If the circuit tests normal, replace the X50A Fuse Block - Underhood.

•	G10 Cooling Fan Motor low speed control terminal 2

•	G10 Cooling Fan Motor medium speed control terminal 3

•	G10 Cooling Fan Motor high speed control terminal 4

3. Ignition OFF, disconnect the harness connector X1 at the K20 Engine Control Module. Test for infinite resistance between the relay coil control circuit terminals listed below and ground.

•	KR20P Cooling Fan Medium Speed Relay control terminal 85

•	KR20C Cooling Fan Low Speed Relay control terminal 85

⇒	If less than the specified value, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the X50A Fuse Block - Underhood.

4. Connect the KR20P Cooling Fan Medium Speed Relay.
5. Ignition ON, verify the G10 Cooling Fan Motor is not activated.

⇒	If the G10 Cooling Fan Motor is activated, test or replace the KR20P Cooling Fan Medium Speed Relay.

6. Ignition OFF, connect the KR20C Cooling Fan Low Speed Relay.
7. Ignition ON, verify the G10 Cooling Fan Motor is not activated.

⇒	If the G10 Cooling Fan Motor is activated, test or replace the KR20C Cooling Fan Low Speed Relay.

8. Ignition OFF, connect the KR20D Cooling Fan High Speed Relay.
9. Ignition ON, verify the G10 Cooling Fan Motor is not activated.

⇒	If the G10 Cooling Fan Motor is activated, test or replace the KR20D Cooling Fan High Speed Relay.

10. If all circuit tests normal, replace the K20 Engine Control Module.

Component Testing

Dynamic Test

1. Ignition OFF, disconnect the applicable relay.
2. Test for 70-110 Ω between terminals 85 and 86 of the relay.

⇒	If the resistance is not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the relay.

4. Install a 20 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.

⇒	If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.