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 and Stop Lamp Switch Adjustment 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 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 and Park/Neutral Position Switch Adjustment for service procedure.

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

--