2010 Cadillac Truck SRX AWD V6-2.8L Turbo Page 1505
2. Ignition ON, test for 4.8-5.2 V between one of the affected 5 V reference circuits and ground.
瀚慖f the voltage is less than the specified range, test for a short to ground on the 5 V reference circuit for each of the affected components. If
all circuits test normal, replace the K20 ECM.
瀚慖f the voltage is greater than the specified range, test for a short to voltage on the 5 V reference circuit for each of the affected
components. If all circuits test normal, replace the K20 ECM.
Note: A short to voltage on the signal circuit of certain components may cause this DTC to set.
3. Connect each component associated with the affected 5 V reference circuit one at a time while monitoring the appropriate scan tool 5 V
Reference Circuit Voltage parameter. Verify the voltage remains between 4.8-5.2 V.
瀚慖f not within the specified range when a component is connected, test the signal circuit of that component for a short to voltage. If the
circuit tests normal, replace the component.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Accelerator Pedal with Position Sensor Assembly Replacement (See: Powertrain Management/Fuel Delivery and Air Induction/Accelerator
Pedal/Service and Repair/Accelerator Pedal with Position Sensor Assembly Replacement)
* Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (LF1) (See: Heating and Air Conditioning/Refrigerant Pressure Sensor /
Switch/Service and Repair)Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (LAU) (See: Heating and Air
Conditioning/Refrigerant Pressure Sensor / Switch/Service and Repair)
* Camshaft Position Sensor Replacement - Bank 1 (Right Side) Intake (See: Powertrain Management/Computers and Control
Systems/Camshaft Position Sensor/Service and Repair/Camshaft Position Sensor Replacement - Bank 1 (Right Side) Intake)
* Camshaft Position Sensor Replacement - Bank 1 (Right Side) Exhaust (See: Powertrain Management/Computers and Control
Systems/Camshaft Position Sensor/Service and Repair/Camshaft Position Sensor Replacement - Bank 1 (Right Side) Exhaust)
* Camshaft Position Sensor Replacement - Bank 2 (Left Side) Intake (See: Powertrain Management/Computers and Control
Systems/Camshaft Position Sensor/Service and Repair/Camshaft Position Sensor Replacement - Bank 2 (Left Side) Intake)
* Camshaft Position Sensor Replacement - Bank 2 (Left Side) Exhaust (See: Powertrain Management/Computers and Control
Systems/Camshaft Position Sensor/Service and Repair/Camshaft Position Sensor Replacement - Bank 2 (Left Side) Exhaust)
* Crankshaft Position Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Crankshaft Position
Sensor/Service and Repair)
* Fuel Injector Replacement (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Injector/Service and Repair)
* Fuel Tank Pressure Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Fuel Tank Pressure Sensor/Service
and Repair)
* Secondary Injection Shutoff Valve Pressure Sensor Replacement (See: Powertrain Management/Emission Control Systems/Air Injection/Air
Injection Check Valve/Service and Repair)
* Throttle Body Assembly Replacement (LF1) (See: Powertrain Management/Fuel Delivery and Air Induction/Throttle Body/Service and
Repair/Removal and Replacement)Throttle Body Assembly Replacement (LAU) (See: Powertrain Management/Fuel Delivery and Air
Induction/Throttle Body/Service and Repair/Removal and Replacement)
* Turbocharger Pressure Sensor Replacement (See: Powertrain Management/Fuel Delivery and Air Induction/Turbocharger/Service and
Repair/Turbocharger Pressure Sensor Replacement)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
P0643
DTC P0641-P0643, P0651-P0653, or P0697-P0699 (ECM, LAU)
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 P0641
- 5 V Reference 1 Circuit
DTC P0642
- 5 V Reference 1 Circuit Low Voltage
DTC P0643
- 5 V Reference 1 Circuit High Voltage
