2010 Cadillac CTS Sedan AWD V6-3.0L Page 1464

2010 Cadillac CTS Sedan AWD V6-3.0L Page 1464

Caution: Support the lower control arms in the normal horizontal position in order to avoid damage to the drive axles. Do not operate the

vehicle in gear with the wheels hanging down at full travel.

2. Support the lower control arms so that the drive axles are in a horizontal position.

3. Start and idle the engine.

4. Place the transmission in second gear and release the clutch pedal.

5. Monitor VSS parameter on the scan tool. The VSS parameter should increase as the drive wheel speed increases.

6. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in

the Freeze Frame/Failure Records List.

Circuit/System Testing

1. Disconnect the ECM harness connector X1.

2. Measure for 1,300-1,500 ohms at 25掳C (77掳F) between the VSS high signal circuit terminal 66 and the VSS low signal circuit terminal 67.

瀚慖f the value is greater than 1,500 ohms test the VSS high signal circuit and the VSS low signal circuit for an open/high resistance. If the

circuits/connections test normal, replace the vehicle speed sensor.

瀚慖f the value is less than 1,300 ohms test the VSS high signal and the VSS low signal circuits for a shorted together condition. If the

circuits/connections test normal, replace the vehicle speed sensor.

3. Measure for more than 10 ohms of resistance between the VSS high signal circuit terminal 66 and ground.

瀚慖f the value is less than the specified range, repair the short to ground.

4. Measure for more than 10 ohms of resistance between the VSS low signal circuit terminal 67 and ground.

瀚慖f the value is less than the specified range, repair the short to ground.

5. Reconnect the ECM connector. Disconnect the VSS connector.

6. Ignition ON, test the VSS high signal circuit terminal B for a short to voltage.

瀚慖f all circuits/connections test normal, test or replace the VSS.

Repair Instructions

Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the repair.

* Vehicle Speed Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Sensors and Switches - Computers and

Control Systems/Vehicle Speed Sensor/Service and Repair/Tremec 6-Speed - Manual Transmission)

* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup and programming

P0506

DTC P0506 or P0507 (LF1)

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 P0506

- Idle Speed Low

DTC P0507

- Idle Speed High

Circuit/System Description

The throttle actuator control (TAC) motor is a DC motor that is part of the throttle body assembly. The TAC motor drives the throttle valve. The

engine control module (ECM) controls the TAC motor based on throttle position sensor input. The idle speed is controlled by the ECM based on

various inputs. The ECM commands the TAC motor to open or close the throttle valve in order to maintain the desired idle speed.