2010 Cadillac CTS Sedan AWD V6-3.6L Page 1554
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 Status parameter. The parameter should continue to display OK.
瀚慖f the parameter displays Fault 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.
* Fuel Tank Pressure Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Fuel Tank Pressure Sensor/Service
and Repair)
* Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LF1) (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel
Pressure Sensor/Switch/Service and Repair)Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LLT) (See: Powertrain
Management/Fuel Delivery and Air Induction/Fuel Pressure Sensor/Switch/Service and Repair)
* Engine Oil Pressure Sensor and/or Switch Replacement (See: Engine, Cooling and Exhaust/Engine/Engine Lubrication/Oil Pressure
Sensor/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)
* Accelerator Pedal Position Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Accelerator Pedal Position
Sensor/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 (LLT) (See: Powertrain Management/Fuel Delivery and Air
Induction/Throttle Body/Service and Repair/Removal and Replacement)
* Crankshaft Position Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Crankshaft Position
Sensor/Service and Repair)
* Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (See: Heating and Air Conditioning/Refrigerant Pressure Sensor /
Switch/Service and Repair)
* Clutch Pedal Position Switch Replacement (See: Powertrain Management/Transmission Control Systems/Sensors and Switches -
Transmission and Drivetrain/Sensors and Switches - M/T/Clutch Pedal Position Sensor / Switch/Service and Repair)
P0645
DTC P0645, P0646, or P0647
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 P0645
- Air Conditioning (A/C) Clutch Relay Control Circuit
DTC P0646
- Air Conditioning (A/C) Clutch Relay Control Circuit Low Voltage
DTC P0647
- Air Conditioning (A/C) Clutch Relay Control Circuit High Voltage
Diagnostic Fault Information
