GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2002 🢒 DeVille 🢒 Transmission/Transaxle 🢒 Shift Lock Control 🢒 Shift Lever Can Be Moved without Brake Pedal Depressed

Shift Lever Can Be Moved without Brake Pedal Depressed DHS

Step

Action

Yes

No

Schematic Reference: Shift Lock Control Schematics

DEFINITION: Transmission shift lever does not lock in the PARK position with the ignition ON and the brake pedal not pressed.

1

Did you perform the Automatic Transmission Shift Lock Control System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission Shift Lock Control

2
  1. Apply the parking brake and block the wheels.
  2. Turn ON the ignition, with the engine OFF.
  3. Attempt to move the shift lever out of the PARK position.

Does the shift lever move out of the PARK position?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3
  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Ensure that the transmission shift lever is in the PARK position.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the brake-to-shift-relay status in the rear integration module (RIM) data list.

Does the scan tool display ON status?

Go to Step 4

Go to Step 16

4
  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock control switch supply voltage circuit at the automatic transmission shift lock control switch and a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 10

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Connect a test lamp between the supply voltage circuit of the automatic transmission shift lock control switch at the park relay and a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 17

Go to Step 6

6
  1. Turn OFF the ignition.
  2. Disconnect the brake to shift relay.
  3. Connect a test lamp between the brake to shift relay coil side feed circuit of the brake to shift relay coil and a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 7

Go to Step 18

7

Connect a test lamp between the switch side feed circuit of the brake to shift relay and a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 19

8
  1. Turn OFF the ignition.
  2. Connect a test lamp between the coil side feed circuit and the control circuit of the brake to shift relay at the relay connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the brake to shift relay ON and OFF several times.

Does the test lamp turn ON and OFF with each command?

Go to Step 13

Go to Step 9

9

Test of a open or short in the brake to shift relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 26

Go to Step 16

10
  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock solenoid supply voltage circuit at the automatic transmission shift lock control switch and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 11

Go to Step 14

11
  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock control solenoid supply voltage circuit at the automatic transmission shift lock control solenoid and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 12

Go to Step 20

12
  1. Turn OFF the ignition.
  2. Disconnect the automatic transmission shift lock control solenoid.
  3. Connect a test lamp between supply voltage circuit and the ground circuit of the automatic transmission shift lock control solenoid.
  4. Turn ON the ignition, with the engine OFF.
  5. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 15

Go to Step 21

13

Inspect for poor harness connections at the brake to shift relay. 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 26

Go to Step 22

14

Inspect for poor harness connections at the automatic transmission shift lock control switch. 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 26

Go to Step 23

15

Inspect for poor harness connections at 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 26

Go to Step 24

16

Inspect for poor harness connections at the rear integration module (RIM). 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 26

Go to Step 25

17

Repair the open in the A/T shift lock control switch supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 26

--

18

Repair the open in the brake to shift relay coil side feed circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 26

--

19

Repair the open in the brake to shift relay switch side feed circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 26

--

20

Repair the open in A/T shift lock control solenoid supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 26

--

21

Repair the open in the automatic transmission shift lock control solenoid ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 26

--

22

Replace the brake to shift relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement?

Go to Step 26

--

23

Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the repair?

Go to Step 26

--

24

Replace the automatic transmission shift lock control solenoid. Refer to Transmission Control Replacement in Automatic Transaxle - 4T80-E.

Did you complete the replacement?

Go to Step 26

--

25

Replace the rear integration module (RIM) Refer to Rear Integration Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 26

--

26

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2

Shift Lever Can Be Moved without Brake Pedal Depressed DTS

Step

Action

Yes

No

Schematic Reference: Shift Lock Control Schematics

DEFINITION: Transmission shift lever does not lock in the PARK position with the ignition ON and the brake pedal not pressed.

1

Did you perform the Automatic Transmission Shift Lock Control System Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Automatic Transmission Shift Lock Control

2
  1. Apply the parking brake and block the wheels.
  2. Turn ON the ignition, with the engine OFF.
  3. Attempt to move the shift lever out of the PARK position.

Does the shift lever move out of the PARK position?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

3
  1. Turn OFF the ignition.
  2. Install a scan tool.
  3. Ensure that the transmission shift lever is in the PARK position.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observer the brake to shift relay status in the rear integration module (RIM) data list.

Does the scan tool display ON status?

Go to Step 4

Go to Step 18

4
  1. Turn OFF the ignition.
  2. Connect a test lamp between the supply voltage circuit of the automatic transmission shift lock control switch and a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 10

Go to Step 5

5
  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock control switch supply voltage circuit at the park relay and a good ground.
  3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 19

Go to Step 6

6
  1. Turn OFF the ignition.
  2. Disconnect the brake to shift relay.
  3. Connect a test lamp between the coil side feed circuit of the brake to shift relay and a good ground.
  4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 7

Go to Step 20

7

Connect a test lamp between the switch side feed circuit of the brake to shift relay and a good ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 21

8
  1. Turn OFF the ignition.
  2. Connect a test lamp between the coil side feed circuit and the control circuit of the brake to shift relay at the connector.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, command the brake to shift relay ON and OFF several times.

Does the test lamp turn ON and OFF with each command?

Go to Step 15

Go to Step 9

9

Test of a open or short in the brake to shift relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 18

10
  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock control solenoid supply voltage circuit at the automatic transmission shift lock control switch and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 11

Go to Step 16

11
  1. Turn OFF the ignition.
  2. Connect a test lamp between the automatic transmission shift lock control solenoid supply voltage circuit at the shift lock relay and a good ground.
  3. Turn ON the ignition, with the engine OFF.
  4. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 12

Go to Step 22

12
  1. Turn OFF the ignition.
  2. Disconnect the shift lock relay.
  3. Press and hold the brake pedal.
  4. Turn ON the ignition, with the engine OFF.
  5. Attempt to move the shift lever out of the park position.

Does the shift lever move out of the park position?

Go to Step 17

Go to Step 13

13
  1. Turn OFF the ignition.
  2. Connect a test lamp between the A/T shift lock control solenoid supply voltage circuit and the shift lock relay ground circuit at the shift lock relay connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 14

Go to Step 23

14

Inspect for poor harness connections at the shift lock relay. 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 29

Go to Step 24

15

Inspect for poor harness connections at the brake to shift relay. 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 29

Go to Step 25

16

Inspect for poor harness connections at the automatic transmission shift lock control switch. 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 29

Go to Step 26

17

Inspect for poor harness connections at 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 29

Go to Step 27

18

Inspect for poor harness connections at the rear integration module (RIM). 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 29

Go to Step 28

19

Repair the open in the A/T shift lock control switch supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

20

Repair the open in the brake to shift relay coil side feed circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

21

Repair the open in the brake to shift relay switch side feed circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

22

Repair the open in automatic transmission shift lock control solenoid supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

23

Repair the open in the shift lock relay ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

24

Replace the shift lock relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement?

Go to Step 29

--

25

Replace the brake to shift relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the replacement?

Go to Step 29

--

26

Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Did you complete the repair?

Go to Step 29

--

27

Replace the automatic transmission shift lock control solenoid. Refer to Transmission Control Replacement in Automatic Transaxle - 4T80-E.

Did you complete the replacement?

Go to Step 29

--

28

Replace the rear integration module (RIM). Refer to Rear Integration Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 29

--

29

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2