2010 Cadillac CTS Sedan AWD V6-3.6L Page 1470
Control Module References (See: Testing and Inspection/Programming and Relearning)
Circuit/System Verification
1. Operate the vehicle on the road at 40 MPH. Observe the transmission vehicle speed sensor parameter with a scan tool. The VSS signal should
match the instrument panel speedometer indicator.
2. Operate the vehicle within the Conditions for Running the DTC, to verify the DTC does not reset. You may also operate the vehicle within
the conditions that you observed from the Freeze Frame/Failure Records.
Circuit/System Testing
1. Ignition OFF, disconnect the X2 harness connector at the ECM.
2. Disconnect the VSS harness connector.
3. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit at the VSS harness connector terminal 2 and ground.
瀚慖f greater than the specified value, repair the open/high resistance condition.
4. Ignition ON, test for less than 1 volt between the signal circuit terminal 1 and ground at the VSS harness connector.
瀚慖f greater than the specified value, test the signal circuit for a short to voltage.
5. Ignition ON, test for greater than 11 volts between the ignition voltage circuit, at the VSS harness connector terminal 3, and ground.
瀚慖f less than the specified value, test the ignition voltage circuit for a short to ground or an open/high resistance.
6. Ignition ON, install a 3A fused jumper wire between the ignition voltage circuit terminal 3 and the signal circuit terminal 1 at the VSS
harness connector. Test for greater than 11 volts at X2, terminal 43 of the ECM harness connector.
瀚慖f less than the specified value, test the VSS signal circuit for a short to ground, or an open/high resistance.
7. Remove the 3A fused jumper wire.
8. Ignition ON, engine OFF, transmission in NEUTRAL.
9. Install a 3A fused jumper wire between the ignition voltage circuit terminal 1 on the VSS harness connector and terminal 1 on the VSS.
Connect a second jumper wire between the ground circuit terminal 2 on the VSS harness connector and terminal 2 on the VSS.
10. Test for greater than 0.15 volts AC, at terminal 1 on the VSS sensor, while rotating the rear wheels by hand.
瀚慖f less than the specified value, replace the VSS.
11. If all circuits test normal, replace the ECM.
Component Testing
1. Remove the VSS sensor. Refer to Vehicle Speed Sensor Replacement (See: Powertrain Management/Computers and Control
Systems/Sensors and Switches - Computers and Control Systems/Vehicle Speed Sensor/Service and Repair/Aisin AY6 - Manual
Transmission).
2. Inspect and repair the VSS or the transmission for the following conditions:
* Loose or damaged VSS
* Excessive VSS to rotor gap
* Incorrect VSS rotor alignment
* Loose or damaged VSS rotor
Repair Instructions
* Vehicle Speed Sensor Replacement (See: Powertrain Management/Computers and Control Systems/Sensors and Switches - Computers and
Control Systems/Vehicle Speed Sensor/Service and Repair/Aisin AY6 - Manual Transmission)
* Engine Control Module Programming and Setup (w/LF1) (See: Powertrain Management/Computers and Control Systems/Engine Control
Module/Testing and Inspection)Engine Control Module Programming and Setup (w/LLT) (See: Powertrain Management/Computers and
Control Systems/Engine Control Module/Testing and Inspection)Engine Control Module Programming and Setup (V8) (See: Powertrain
Management/Computers and Control Systems/Engine Control Module/Testing and Inspection)
* Engine Control Module Replacement (See: Powertrain Management/Computers and Control Systems/Engine Control Module/Service and
Repair)
* Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Tremec 6-Speed - Manual Transmission
DTC P0502 or P0503
Diagnostic Instructions
