For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Shift Lock Control Schematics
1 | Did you perform A Diagnostic System Check - Automatic Transmission Shift Lock Control? | Go to Step 2 | Go to Diagnostic System Check - Automatic Transmission Shift Lock Control
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Command the Brake to Shift Lamp ON and OFF in the body control module output controls data list.

Does the Brake to Shift Lamp turn ON and OFF with each command?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 | Does the Brake to Shift Lamp stay ON? | Go to Step 7 | Go to Step 4
4 | Does the Check Engine and Air Bag lamp illuminate when the ignition is turned to the run position? | Go to Step 5 | Go to Step 6
5 |

1. Turn OFF the ignition.
2. Connect a test lamp between the brake to shift lamp control circuit at the instrument panel connector and battery positive voltage.
3. Turn ON the ignition, with the engine OFF.
4. Command the Brake to Shift Lamp ON and OFF in the body control module output controls data list.

Does the test lamp turn ON and OFF with each command?

Go to Step 9

Go to Step 8

6 |

1. Turn OFF the ignition.
2. Connect a test lamp between the voltage supply circuit of the brake to shift lamp at the instrument panel cluster and a good ground.
3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 10

Go to Step 12

7 | Test for a short to ground in the brake to shift lamp control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 11
8 | Test for an open in the brake to shift lamp control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 13
9 | Inspect for poor connections at the brake to shift lamp bulb. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 13
10 | Inspect for poor connections at the harness connector of the instrument panel cluster. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 14
11 | Inspect for poor connections at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 16 | Go to Step 15
12 | Repair open in the brake to shift lamp voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 16 | --
13 | Replace the brake to shift lamp bulb. Refer to Instrument Cluster Indicator Lamp Replacement in Instrument Panel, Gauges, and Console. Did you complete the repair? | Go to Step 16 | --
14 | Replace the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges, and Console. Did you complete the repair? | Go to Step 16 | --
15 | Replace the body control module (BCM). Refer to Body Control Module Replacement in Body Control System. Did you complete the replacement? | Go to Step 16 | --
16 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2