Contents Wiring diagrams Section: Automatic Trans All sections

Shift Interlock System: Other Cadillac STS I

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Shift Lever Does Not Move with Brake Pedal Depressed

StepActionYesNo
Schematic Reference: Automatic Transmission Shift Lock Control Schematics Connector End View Reference: Automatic Transmission Shift Lock Control Connector End Views or Keyless Entry Connector End Views in Keyless Entry DEFINITION: Transmission shift lever does not move out of the PARK position with the ignition ON and the brake pedal depressed.
1Did you perform the A Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Apply the parking brake and block the wheels. Turn ON the ignition, with the engine OFF. Attempt to move the shift lever out of the PARK position without pressing the brake pedal. Does the shift lever move out of the PARK position?Go to Testing for Intermittent Conditions and Poor Connections in Wiring SystemsGo to Step 3
3Turn OFF the ignition. Install a scan tool. Turn ON the ignition, with the engine OFF. Press and hold the brake pedal. With a scan tool, observe the shift lock control output in the remote control door lock receiver (RCDLR) data list. Does the scan tool display an Active status?Go to Step 5Go to Step 4
4With a scan tool, observe the brake switch input in the transmission control module (TCM) data list. Does the brake switch status indicate Active?Go to Step 8Go to Stop Lamps Inoperative in Lighting Systems
5Turn OFF the ignition. Connect a test lamp at the shift lock control solenoid voltage supply circuit at the connector of the shift lock control solenoid and a good ground. Turn ON the ignition, with the engine OFF. Does the test lamp illuminate?Go to Step 6Go to Step 10
6Turn OFF the ignition. Disconnect the harness connector of the automatic transmission shift lock control solenoid. Connect a test lamp between the shift lock control solenoid voltage supply circuit and the shift lock control solenoid control circuit at the connector of the shift lock control solenoid. Turn ON the ignition, with the engine OFF. With a scan tool, command the shift lock control output ON and OFF several times. Does the test lamp turn ON and OFF with each command?Go to Step 8Go to Step 7
7Test the control circuit of the automatic transmission shift lock control solenoid for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 9
8Inspect for poor connections at the harness connector of the automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 11
9Inspect for poor connections at the harness connector of the RCDLR. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 13Go to Step 12
10Repair the open or short to ground in the automatic transmission shift lock control solenoid voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair?Go to Step 13
11Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement?Go to Step 13
12Replace the RCDLR. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 13
13Operate the system in order to verify the repair. Did you find and correct the condition?System OKGo to Step 2

Shift Lever Does Not Move with Brake Pedal Depressed

Shift Lever Can Be Moved without Brake Pedal Depressed

StepActionYesNo
Schematic Reference: Automatic Transmission Shift Lock Control Schematics Connector End View Reference: Automatic Transmission Shift Lock Control Connector End Views or Keyless Entry Connector End Views in Keyless Entry DEFINITION: Transmission shift lever does not lock in the PARK position with the ignition ON and the brake pedal not depressed.
1Did you perform the A Diagnostic System Check - Vehicle?Go to Step 2Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2Apply the parking brake and block the wheels. Turn ON the ignition, with the engine OFF. Attempt to move the shift lever out of the PARK position without pressing the brake pedal. Does the shift lever move out of the PARK position?Go to Step 3Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems
3Turn OFF the ignition. Install a scan tool. Turn ON the ignition, with the engine OFF. Ensure brake pedal is released. With a scan tool, observe the shift lock control output in the remote control door lock receiver (RCDLR) data list. Does the scan tool display an Active status?Go to Step 4Go to Step 5
4With a scan tool, observe the brake switch input in the transmission control module (TCM) data list. Does the brake switch status indicate Inactive?Go to Step 8Go to Stop Lamps Always On in Lighting Systems
5Turn OFF the ignition. Disconnect the electrical connector of the shift lock control solenoid. Apply the parking brake and block the wheels. Turn ON the ignition, with the engine OFF. Attempt to move the shift lever out of the PARK position. Does the shift lever move out of the park position?Go to Step 7Go to Step 6
6Test the shift lock control solenoid control circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 8
7Inspect for poor connections at the harness connector of the automatic transmission shift lock control solenoid. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 9
8Inspect for poor connections at the harness connector of the RCDLR. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?Go to Step 11Go to Step 10
9Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement?Go to Step 11
10Replace the RCDLR. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement?Go to Step 11
11Operate the system in order to verify the repair. Did you find and correct the condition?System OKGo to Step 2

Shift Lever Can Be Moved without Brake Pedal Depressed