GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

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

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Go to Step 2

Go to Automatic Transmission Shift Lock Control System Check

2

  1. Turn the ignition switch to RUN.
  2. Connect a scan tool to the data link connector (DLC).
  3. Select body control module (SBM).
  4. Check for SBM DTCs.

Do any body control module (SBM) DTCs appear on the scan tool?

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Go to Diagnostic Trouble Code (DTC) List/Type in Body Control System

Go to Step 3

3

  1. Turn the ignition switch to OFF.
  2. Disconnect the stoplamp/BTSI switch connector C1.
  3. Turn the ignition switch to RUN.
  4. Connect a J 39200 digital multimeter (DMM) between the stoplamp/BTSI switch connector C1 terminal A and ground.

Is the measured voltage within the specified range?

10-15V

Go to Step 5

Go to Step 4

4

Repair the open in CKT 275 (LT GRN).

Is the repair complete?

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Go to Step 12

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5

  1. Ensure that the brake pedal is not pressed.
  2. Connect a DMM between the stoplamp/BTSI switch connector C1 terminals A and B.

Is the measured voltage within the specified range?

10-15V

Go to Step 6

Go to Step 7

6

  1. Inspect the stoplamp/BTSI switch connector for poor terminal contact.
  2. If OK, replace the stoplamp/BTSI switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes.

Is the repair complete?

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Go to Step 12

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7

  1. Turn the ignition switch to OFF.
  2. Reconnect the stoplamp/BTSI switch connector C1.
  3. Disconnect the shift interlock actuator connector.
  4. Connect a DMM between the shift interlock actuator connector terminal A and ground.
  5. Turn the ignition switch to RUN.

Is the measured voltage within the specified range?

10-15V

Go to Step 8

Go to Step 9

8

Repair the open in CKT 1135 (DK GRN/WHT).

Is the repair complete?

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Go to Step 12

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9

  1. Turn the ignition switch to OFF.
  2. Connect a DMM set to ohms scale between the shift interlock actuator connector terminal B and ground.

Is the measured resistance within the specified range?

Less than 5ohms

Go to Step 11

Go to Step 10

10

Repair the open in CKT 350 (BLK).

Is the repair complete?

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Go to Step 12

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11

  1. Inspect the shift interlock actuator connector for poor terminal contact.
  2. If OK, replace the shift interlock actuator. Refer to Automatic Transmission Shift Lock Control Disassemble - Off Vehicle and Automatic Transmission Shift Lock Control Assemble - Off Vehicle .

Is the repair complete?

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Go to Step 12

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12

  1. Make sure any components removed during diagnosis are installed in place and that all connectors are connected.
  2. Repeat the system check. Refer to Automatic Transmission Shift Lock Control System Check .

Is the system check complete?

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System OK

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