GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1999 🢒 Eldorado 🢒 Steering 🢒 Steering Wheel and Column - Tilt 🢒 Automatic Transmission Shift Lock Control Inoperative

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. Connect a scan tool to the data link connector (DLC).
  2. Turn the ignition switch to RUN.
  3. Select the body control module (PZM).
  4. Retrieve the PZM diagnostic trouble codes (DTCs).

Is PZM DTC B2502 or B2503 present?

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

Go to Step 3

3

Check the PARK/REV fuse in the underhood fuse block.

Is the fuse open?

--

Go to Step 4

Go to Step 5

4
  1. Repair the short to ground on CKT 1940 (ORN). Refer to Wiring Repairs in Wiring Systems.
  2. Replace the PARK/REV fuse in the underhood fuse block.

Is the repair complete?

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Go to Step 27

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5

Check the CRUISE fuse in the underhood fuse block.

Is the fuse open?

--

Go to Step 7

Go to Step 6

6
  1. Repair the short to ground on CKT 339 (PNK). Refer to Wiring Repairs in Wiring Systems.
  2. Replace the CRUISE fuse in the underhood fuse block.

Is the repair complete?

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Go to Step 27

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7
  1. Turn the ignition switch to OFF.
  2. Remove the PARK relay.
  3. Turn the ignition switch to RUN.
  4. Using a J 39200 digital multimeter (DMM), check the voltage from the PARK relay connector terminal A1 to ground.

Is the measured voltage within the specified range?

10-15 V

Go to Step 9

Go to Step 8

8

Repair the open in CKT 1940 (ORN).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 27

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9

Using a DMM, check the voltage from the PARK relay connector terminal A3 to ground.

Is the measured voltage within the specified range?

10-15 V

Go to Step 11

Go to Step 10

10

Repair the open in CKT 339 (PNK).

Is the repair complete?

--

Go to Step 27

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11
  1. Turn the ignition switch to OFF.
  2. Connect a fused jumper between the PARK relay connector terminals A1 and B3. Refer to Using Fused Jumper Wires in Wiring Systems.
  3. Turn the ignition switch to RUN.
  4. Attempt to shift the vehicle out of PARK.

Is the gear shift locked?

--

Go to Step 21

Go to Step 12

12
  1. Disconnect the stoplamp/BTSI switch connector C2.
  2. Using a DMM, check the voltage from the stoplamp/BTSI switch connector C2 terminal A to ground. Refer to Measuring Voltage in Wiring Systems.

Is the measured voltage within the specified range?

10-15 V

Go to Step 14

Go to Step 13

13

Repair the open in CKT 275 (LT GRN).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 27

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14

Measure the voltage with a DMM across the stoplamp/BTSI switch connector C2 terminals A and B.

Refer to Wiring Repairs in Wiring Systems.

Is the measured voltage within the specified range?

10-15 V

Go to Step 16

Go to Step 15

15
  1. Ensure that the stoplamp/BTSI switch is properly adjusted.
  2. Ensure that the connector C2 terminals are clear and tight.
  3. 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 27

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16
  1. Reconnect the stoplamp/BTSI switch connector C2.
  2. Disconnect the shift interlock actuator connector.
  3. Using a DMM, check the voltage from the shift interlock actuator connector terminal A to ground.

Refer to Measuring Voltage in Wiring Systems.

Is the measured voltage within the specified range?

10-15 V

Go to Step 18

Go to Step 17

17

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

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 27

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18

Connect a DMM across the shift interlock actuator connector terminals A and B.

Refer to Wiring Repairs in Wiring Systems.

Is the measured voltage within the specified range?

10-15 V

Go to Step 20

Go to Step 19

19

Repair the open CKT 50 (BLK) or CKT 850 (BLK).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

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Go to Step 27

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20
  1. Ensure that the shift interlock actuator connector terminals are clean and tight.
  2. If OK, replace the shift interlock actuator. Refer to Brake Transmission Shift Interlock Solenoid Replacement .

Is the repair complete?

--

Go to Step 27

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21
  1. Turn the ignition switch to OFF.
  2. Remove the fused jumper.
  3. Install the PARK relay.
  4. Turn the ignition switch to RUN.
  5. Using the scan tool , select the PZM, then the PZM data function.

Does the PZM as monitored by the scan tool indicate that the vehicle is in PARK?

--

Go to Step 22

Go to Powertrain On Board Diagnostic (OBD) System Check in Engine Controls - 4.6L

22
  1. Turn the ignition switch to OFF.
  2. Disconnect the body control module (PZM) connector C2.
  3. Connect a fused jumper from the PZM connector C2 terminal C16 to ground.
  4. Turn the ignition switch to RUN.
  5. Attempt to shift the vehicle out of PARK.

Is the gear shifter locked?

--

Go to Step 26

Go to Step 23

23

Inspect CKT 434 (ORN/BLK) for an open.

Is the circuit OK?

--

Go to Step 25

Go to Step 24

24

Repair the open in CKT 434 (ORN/BLK).

Refer to Wiring Repairs in Wiring Systems.

Is the repair complete?

--

Go to Step 27

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25
  1. Inspect the PARK relay connector for poor terminal contact.
  2. If OK, replace the PARK relay.

Is the repair complete?

--

Go to Step 27

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26
  1. Inspect the body control module (PZM) connector C2 for poor terminal contact.
  2. If OK, replace the PZM. Refer to Body Control Module Replacement in Body Control System.

Is the repair complete?

--

Go to Step 27

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27
  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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