GM Service Manual Online
For 1990-2009 cars only

Automatic Transmission Shift Lock Control Diagnosis Transmission May Be Shifted

Step

Action

Value(s)

Yes

No

DEFINITION: The transmission may be shifted from park without the actuation of the brake pedal and with the ignition switch in the RUN position.

1

Has the BTSI System Check been performed?

--

Go to Step 2

Go to Automatic Transmission Shift Lock Control System Check

2

  1. Disconnect the brake transmission shift interlock (BTSI) connector.
  2. Connect a J 39200 between cavity B of BTSI connector and B+.

Is there battery voltage?

--

Go to Step 4

Go to Step 3

3

Locate and repair the open in CKT 150 (BLK) between cavity B of the BTSI connector and ground. Refer to Wiring Repairs in wiring.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

 

4

  1. Place the transmission in the P position.
  2. Turn the ignition to the RUN position.
  3. Connect a J 39200 between cavity A of the BTSI connector and B+.

Is there battery voltage?

--

Go to Step 5

Go to Step 6

5

Adjust or replace the BTSI solenoid. Refer to Automatic Transmission Shift Lock Control Disassemble - Off Vehicle or Automatic Transmission Shift Lock Control Assemble - Off Vehicle .

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

 

6

  1. Disconnect the stoplamp switch connector.
  2. Connect a J 39200 between cavity F of the stoplamp switch connector and cavity A of the BTSI connector.

Is there continuity?

--

Go to Step 8

Go to Step 7

7

Locate and repair the open in CKT 1135 (GRN/WHT) between the stoplamp switch connector and the BTSI connector. Refer to Wiring Repairs iin wiring.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

 

8

Connect a J 39200 between cavity E of the stoplamp switch connector and B+.

Is there battery voltage?

--

Go to Step 9

Go to Step 10

9

Replace the stoplamp switch. Refer to Stop Lamp Switch Replacement in brakes.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

10

  1. Disconnect park/neutral position (PNP) switch connector.
  2. Connect a J 39200 between cavity B of PNP connector C1 and cavity E of stoplamp switch connector.

Is there continuity?

--

Go to Step 12

Go to Step 11

11

Locate and repair the open in CKT 275 (LTGRN) between PNP switch connector C1 cavity B and cavity E of stoplamp switch connector. Refer to Wiring Repairs in wiring.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

12

Connect a J 39200 between cavity C connector C1 of PNP connector and B+.

Is there battery voltage?

--

Go to Step 14

Go to Step 13

13

Locate and repair the open in CKT 139 (PNK) between the PNP switch and the IP fuse block. Refer to Wiring Repairs in wiring.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

14

Adjust or replace the PNP switch. Refer to Park/Neutral Position Switch Adjustment or Park/Neutral Position Switch Replacement in transmission/transaxle.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

Automatic Transmission Shift Lock Control Diagnosis Transmission Will Not Shift

Step

Action

Value(s)

Yes

No

DEFINITION: The transmission will not shift from park with the brake pedal actuated and the ignition switch in the RUN position.

1

Has the BTSI System Check been performed?

--

Go to Step 2

Go to Automatic Transmission Shift Lock Control System Check

2

  1. Ensure that the transmission linkage is properly adjusted. Refer to Shift Cable Adjustment in transmission/transaxle.
  2. with a J 39200 backprobe cavity F of the stoplamp switch connector to ground.
  3. Depress the brake pedal.

Is there battery voltage?

--

Go to Step 4

Go to Step 3

3

  1. Disconnect brake transmission shift interlock (BTSI) soleniod connector.
  2. Disconnect the stoplamp switch connector.
  3. Connect a J 39200 between cavity A of the BTSI connector and ground.

Is there battery voltage?

--

Go to Step 6

Go to Step 5

4

Replace the stoplamp switch. Refer to Stop Lamp Switch Replacement in brakes.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

5

  1. Inspect for mechanical binding.
  2. Adjust or replace the brake transmission shift interlock (BTSI) solenoid . Refer to Automatic Transmission Shift Lock Control Disassemble - Off Vehicle or Automatic Transmission Shift Lock Control Assemble - Off Vehicle .

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

6

Repair the short to voltage in CKT 1135 (DKGRN) between the stoplamp switch connector and the BTSI connector. Refer to Wiring Repairs in wiring.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--