2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1936
2. Remove the KR75 powertrain relay.
3. Test for 170-210 ohm between the powertrain relay switched output circuit terminal 87 and the auxiliary coolant pump relay control circuit at
UBEC terminal X2-21.
瀚慖f not within the specified range, replace the X50A UBEC.
4. Test for greater than 2 ohm between UBEC B+ supply cable and the Afterboil PUMP Fuse 4.
瀚慖f less than the specified range, replace the X50A UBEC.
5. Connect a 10 A fused jumper wire from the positive terminal of the battery to the powertrain relay switched output circuit terminal 87.
Connect a jumper wire from the negative terminal of the battery to the auxiliary coolant pump relay control circuit at UBEC terminal X2-21.
Test for less than 2 ohm between UBEC B+ supply cable and the Afterboil PUMP Fuse 4.
瀚慖f greater than the specified range, replace the X50A UBEC.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Fuse Block Replacement (See: Maintenance/Fuses and Circuit Breakers/Fuse Block/Service and Repair/Removal and Replacement/Fuse
Block Replacement)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P2603
DTC P2600-P2603
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P2600
- Auxiliary Coolant Pump Relay Control Circuit
DTC P2601
- Auxiliary Coolant Pump Performance
DTC P2602
- Auxiliary Coolant Pump Relay Control Circuit Low Voltage
DTC P2603
- Auxiliary Coolant Pump Relay Control Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The auxiliary coolant pump and cooling fan system provides a measure of prevention against fuel vaporization due to excessive engine
temperatures. The engine control module (ECM) commands the auxiliary or after boil coolant pump ON when the engine coolant temperature
exceeds a calibrated value after engine shut down. The ECM applies ground to the coil side of the auxiliary pump printed circuit board (PCB) relay.
This energizes the coil and applies voltage directly to the pump motor through the switch side of the relay.
Conditions for Running the DTC
P2600, P2602, or P2603
* The engine speed is greater than 80 RPM.
