2010 Cadillac Truck SRX FWD V6-3.0L Page 1525

2010 Cadillac Truck SRX FWD V6-3.0L Page 1525

- Cooling Fan Relay 1, 2 and 3 operates the fan at a high speed

* When disconnecting or removing fuses and relays from a fuse block, always inspect the component electrical terminals for corrosion and the

correct orientation in the fuse block. Test the mating electrical terminals for tightness.

Reference Information

Schematic Reference

Engine Cooling Schematics (See: Engine, Cooling and Exhaust/Cooling System/Diagrams)

Connector End View Reference

Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)

Description and Operation

Cooling Fan Description and Operation (LAU) (See: Engine, Cooling and Exhaust/Cooling System/Description and Operation/Cooling Fan

Description and Operation)Cooling Fan Description and Operation (LF1) (See: Engine, Cooling and Exhaust/Cooling System/Description and

Operation/Cooling Fan Description and Operation)

Electrical Information Reference

* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit

Testing/Circuit Testing)

* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic

Procedures/Connector Repairs/Connector Repairs)

* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General

Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)

* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring

Repairs/Wiring Repairs)

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code

(DTC) Type Definitions)

Scan Tool Reference

Control Module References (See: Testing and Inspection/Programming and Relearning)for scan tool information

Circuit/System Verification

1. Ignition ON, observe the scan tool parameters listed below. Command the cooling fan ON and OFF with a scan tool. The parameters should

display OK or Not Run in each of the commanded states.

* Cooling Fan Relay 1 Open Circuit Test Status

* Cooling Fan Relay 1 Low Voltage Test Status

* Cooling Fan Relay 1 High Voltage Test Status

2. Engine operating, observe the DTC information with a scan tool. DTC P0480 should not set.

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.

Circuit/System Testing

1. Ignition OFF, disconnect and remove the underhood fuse block (UBEC) and housing.

2. Connect the engine harness connectors X2 and X3 to the UBEC.

3. Connect the red lead of a DMM to the control circuit terminal X1-33. Connect the black lead to ground. Set the DMM on the diode setting.

Ignition ON, the DMM should display OL.

瀚慖f less than the specified range, test the relay coil control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.

4. Command the cooling fan relay ON and OFF at low speed, with a scan tool. The DMM should transition from OL when commanded OFF to

less than 1 V when commanded ON.

瀚慖f the circuit voltage does not correspond to the specified values, test the control circuit for an open/high resistance or for a short to

voltage. If the circuit tests normal, replace the K20 ECM.

5. If all circuits test normal, test or replace the X50A UBEC.

Repair Instructions

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