Cooling Fan Always On - LXV, 2H0
Diagnostic Instructions
Circuit/System Description
The engine control module (ECM) controls cooling fan operation in either high speed or low speed mode, depending on cooling requirements. To activate a fan, the ECM applies ground to the coil side of the applicable fan relay. This energises the coil and applies voltage directly to the cooling fan through the switch side of the relay.
Reference Information
Schematic Reference
Engine Cooling Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Cooling System Description and Operation : 2.0L Diesel LNP → 1.4L LDD and LUJ → 2.0L Diesel LLW
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Ignition ON, observe the DTC information with a scan tool. Verify that DTCs P0691, P0692, P0693 or P0694 are not set.
- Command the cooling fan relay 1 ON and OFF with a scan tool. The cooling fan should operate on low speed when commanded ON, and turn OFF when commanded OFF.
⇒ | If less than the specified value, test the control circuit for a short to ground. |
- Command the cooling fan relay 2 ON and OFF with a scan tool. The cooling fan should operate on medium speed when commanded ON, and turn OFF when commanded OFF.
Circuit/System Testing
- Ignition OFF, disconnect the cooling fan relays.
- Ignition ON, verify that the cooling fans are not operating.
⇒ | If a fan is operating, test the appropriate relay controlled output circuit for a short to voltage. |
- If all circuits test normal, test or replace the cooling fan relay.
Component Testing
Static Test
- Ignition OFF, disconnect the cooling fan relay.
- Test for 70-110 Ω between terminals 85 and 86.
⇒ | If not within the specified range, replace the relay. |
- Test for infinite resistance between the following terminals:
⇒ | If not the specified range, replace the relay. |
- Test for less than 2 Ω between the relay terminals 30 and 87A.
⇒ | If greater than the specified range, replace the relay. |
- Install a 20 A fused jumper wire between relay terminal 85 and B+. Install a jumper wire between the 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.
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