2010 Cadillac CTS Sedan AWD V6-3.0L Page 1553

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1553

1. Ignition OFF, disconnect the harness connector of all appropriate sensors for the applicable DTC. Refer to Diagnostic Aids.

2. Ignition ON, test for 4.8-5.2 V between each 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 or for an open between the ECM and the affected circuit splice. If

the circuit tests 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. If the circuit tests 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 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