For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Shift Lock Control Schematics DEFINITION: Transmission does not shift out of the PARK position with the ignition ON and the brake pedal depressed.
1 | Did you perform the Automatic Transmission Shift Lock Control Diagnostic System Check? | Go to Step 2 | Go to Diagnostic System Check - Automatic Transmission Shift Lock Control
2 |

1. Turn ON the ignition, with the engine OFF.
2. Press and hold the brake pedal.
3. Attempt to move the shift lever out of the PARK position.

Does the shift lever move out of the PARK position?

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

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Connect a test lamp between the A/T shift lock control switch supply voltage circuit at the automatic transmission shift lock control switch and a good ground.
3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 4

Go to Step 12

4 |

1. Connect a test lamp between the A/T shift lock control solenoid supply voltage circuit at the automatic transmission shift lock control switch and a good ground.
2. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 5

Go to Step 9

5 |

1. Connect a test lamp between the A/T shift lock control solenoid supply voltage circuit at the automatic transmission shift lock control solenoid and a good ground.
2. Press the brake pedal ON and OFF several times.

Does the test lamp turn ON and OFF with the brake pedal?

Go to Step 6

Go to Step 13

6 | Connect a test lamp between the park/neutral position switch signal circuit at the automatic transmission shift lock control solenoid and a battery positive voltage. Does the test lamp illuminate? | Go to Step 10 | Go to Step 7
7 | Connect a test lamp between the park/neutral position switch signal circuit at the park neutral/position switch and battery positive voltage. Does the test lamp illuminate? | Go to Step 8 | Go to Step 14
8 | Connect a test lamp between the park/neutral position switch ground circuit at the park/neutral position switch connector and battery positive voltage. Does the test lamp illuminate? | Go to Step 11 | Go to Step 15
9 |

1. Inspect for proper automatic transmission shift lock control switch adjustment. Refer to Stop Lamp Switch Adjustment in Hydraulic Brakes.
2. Inspect for poor connections at the harness connector of the automatic transmission shift lock control switch. 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 19

Go to Step 16

10 | Inspect for poor connections at the harness connector of the automatic transmission shift lock control solenoid. 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 19 | Go to Step 17
11 |

1. Inspect for proper park/neutral position switch adjustment. Refer to Manual Shift Shaft Position Switch Replacement in Automatic Transmissions.
2. Inspect for poor connections at the harness connector of the park/neutral position switch. 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 19

Go to Step 18

12 | Repair the open or high resistance in the A/T shift lock control switch supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
13 | Repair the open or high resistance in the A/T shift lock control solenoid supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
14 | Repair the open or high resistance in the park/neutral position switch signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
15 | Repair the open or high resistance in the park/neutral position switch ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
16 | Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the repair? | Go to Step 19 | --
17 | Replace the automatic transmission shift lock control solenoid. Refer to Shift Control Lever Replacement in Automatic Transmission - 4L30-E. Did you complete the repair? | Go to Step 19 | --
18 | Replace the park/neutral position switch. Refer to Manual Shift Shaft Position Switch Replacement in Automatic Transmission. Did you complete the repair? | Go to Step 19 | --
19 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2