2010 Cadillac Truck SRX FWD V6-3.0L Page 2071
Action Taken When the DTC Sets
The DTCs are Type C DTCs.
Conditions for Clearing the DTC
The DTCs are Type C DTCs.
Diagnostic Aids
* This diagnostic uses a comprehensive approach to the diagnosis of the KR31 auxiliary coolant pump relay and its related circuits. The
auxiliary coolant pump relay is a printed circuit board (PCB) relay. The relay is an integral component to the underhood bussed electrical
center (UBEC). It cannot be removed and it is not visible.
* Much of the diagnosis is performed at the ECM connectors. Great care should be taken to ensure that the correct terminals are tested and the
proper test probes are utilized when performing this diagnostic.
* The test lamp is used to provide a visual aid to observe the integrity of the KR31 relay, the UBEC and the relay control circuit.
* Grounding terminal X2-58 activates the powertrain relay, which will supply power through KR31 relay coil and the relay control circuit.
Under normal circumstances the test lamp will illuminate with dim intensity due to the load created by the KR31 relay coil. If the test lamp
does not illuminate, or illuminates brightly a condition exists in the KR31 relay control circuit or the UBEC.
Reference Information
Schematic Reference
* Engine Cooling Schematics (See: Engine, Cooling and Exhaust/Cooling System/Diagrams)
* Engine Controls Schematics (LAU) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls
Schematics (LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views/Connector End Views By Name)
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, verify that DTC P0480, P0691, or P0692, is not set.
瀚慖f a DTC is set, refer to DTC P0480, P0691, or P0692 (without/LF1) (See: P Code Charts/P0480) for further diagnosis.
Note: There is a slight delay before the cooling fan activates and reaches full speed.
2. Command the cooling fan ON from 20-90 % with a scan tool. Verify that the cooling fan turns ON and operates as commanded.
瀚慖f the cooling fan does not respond to the commanded states, refer to Cooling Fan Inoperative (LAU) (See: Engine, Cooling and
Exhaust/Cooling System/Testing and Inspection/Symptom Related Diagnostic Procedures/Cooling Fan Inoperative)Cooling Fan
Inoperative (LF1) (See: Engine, Cooling and Exhaust/Cooling System/Testing and Inspection/Symptom Related Diagnostic
Procedures/Cooling Fan Inoperative) for further diagnosis.
3. Ignition ON, command the KR31 auxiliary coolant pump relay ON and OFF with the scan tool. An audible click should be heard when
changing between the commanded states.
4. Start the engine, observe the DTC information with a scan tool. DTCs P2600, P2602, or P2603 should not set.
5. Ignition ON, engine off observe the DTC information with a scan tool. DTC P2601 should not set.
