GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Shift the transaxle into PARK.
  2. Check the BTSI fuse for an open.

Is the BTSI fuse open?

--

Go to Step 2

Go to Step 3

2

  1. Disconnect the automatic transmission shift lock control actuator connector.
  2. Using a test light, backprobe between the BTSI fuse terminal C4 and B+. Refer to Fuse Block Schematics for terminal location.

Does the test light illuminate?

--

Go to Step 4

Go to Step 14

3

  1. Turn the ignition switch on.
  2. Using a test light, backprobe between the stop lamp switch connector C2 terminal A and ground.

Does the test light illuminate?

--

Go to Step 5

Go to Step 6

4

  1. Using a test light, backprobe between the BTSI fuse terminal C4 and B+.
  2. Disconnect the stop lamp switch connector C2.

Does the test light illuminate?

--

Go to Step 15

Go to Step 16

5

Using a test light, backprobe between the stop lamp switch connector C2 terminal B and ground.

Does the test light illuminate?

--

Go to Step 7

Go to Step 19

6

Using a test light, backprobe between the BTSI fuse terminal C3 and ground. Refer to Fuse Block Schematics for terminal location.

Does the test light illuminate?

--

Go to Step 17

Go to Step 18

7

  1. Turn the ignition switch off.
  2. Disconnect the automatic transmission shift lock control actuator electrical connector.
  3. Turn the ignition switch on.
  4. Using a test light, backprobe between the automatic transmission shift lock control actuator connector terminal A and ground.

Does the test light illuminate?

--

Go to Step 8

Go to Step 20

8

Using a test light, backprobe the automatic transmission shift lock control actuator connector terminal A and terminal B.

Does the test light illuminate?

--

Go to Step 9

Go to Step 10

9

Check the automatic transmission shift lock control actuator for mechanical damage.

Is there mechanical damage?

--

Go to Step 25

Go to Step 26

10

  1. Turn the ignition switch off.
  2. Reconnect the automatic transmission shift lock control actuator electrical connector.
  3. Using a test light, frontprobe between the underhood accessory wiring junction block connector C1 terminal A12 and B+.

Does the test light illuminate?

--

Go to Step 11

Go to Step 12

11

Using a test light, backprobe between the underhood accessory wiring junction block connector C2 terminal C11 and B+.

Does the test light illuminate?

--

Go to Step 21

Go to Step 22

12

Using a test light, backprobe between transaxle range switch connector C1 terminal A and B+.

Does the test light illuminate?

--

Go to Step 21

Go to Step 13

13

Using a test light, backprobe the transaxle range switch connector C1 terminal D and B+.

Does the test light illuminate?

--

Go to Step 23

Go to Step 24

14

  1. Replace the BTSI fuse.
  2. Reconnect the automatic transmission shift lock control actuator connector.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

15

Repair short to ground in circuit 1439.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

16

Repair short to ground in circuit 1135.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

17

Repair poor connection or open in circuit 1439.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

18

Repair poor connection or open in circuit 3.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

19

Adjust/replace the stoplamp switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes for service procedure.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

20

Repair poor connection or open in circuit 1135.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

21

Repair poor connection or open in circuit 434.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

22

Replace the underhood accessory wiring junction block. Refer to Accessory Wiring Junction Block Replacement in Body Front End for service procedure.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

23

Adjust/replace the transaxle range switch. Refer to Park/Neutral Position Switch Replacement or Park/Neutral Position Switch Adjustment or Park/Neutral Position Switch Replacement in Automatic Transaxle for service procedures.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

24

Repair poor connection or open in circuit 1050.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

25

Refer to Transmission Control Replacement for service procedure.

Is repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--

26

Replace the automatic transmission shift lock control actuator (BTSI). Refer to Brake Transmission Shift Interlock Replacement for service procedure.

Is the repair complete?

--

Go to Automatic Transmission Shift Lock Control System Check

--