For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Shift Lock Control Schematics DEFINITION: Transmission shift lever does not lock in the PARK position with the ignition ON and the brake pedal not pressed.
1 | Did you perform the Symptoms - Automatic Transmission Shift Lock Control tests and all the necessary inspections? | Go to Step 2 | Go to Symptoms - Automatic Transmission Shift Lock Control
2 |

1. Apply the parking brake and block the wheels.
2. Turn ON the ignition, with the engine OFF.
3. Attempt to move the shift lever out of the PARK position.

Does the shift lever move out of the PARK position?

Go to Step 3

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

3 |

1. Turn OFF the ignition.
2. Connect a test lamp between the Ignition 1 circuit at the park/neutral position 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. Ensure transmission shift lever is in the PARK position.
2. Connect a test lamp between the park/neutral position switch park signal circuit at the park/neutral position switch and a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 9

5 | Connect a test lamp between the park/neutral position switch park signal circuit at the automatic transmission shift lock control switch and a good ground. Does the test lamp illuminate? | Go to Step 6 | Go to Step 13
6 |

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 and release the brake pedal several times.

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

Go to Step 7

Go to Step 10

7 |

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

Does the test lamp illuminate?

Go to Step 8

Go to Step 14

8 | Connect a test lamp between the ground circuit at the automatic transmission shift lock control solenoid and battery positive voltage. Does the test lamp illuminate? | Go to Step 11 | Go to Step 15
9 | 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 16
10 | 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 17
11 | 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 18
12 | Repair the open in the ignition 1 power feed circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
13 | Repair the open in the park/neutral position switch park signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
14 | Repair the open in the A/T shift lock control solenoid voltage supply circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
15 | Repair the open in the automatic transmission shift lock control solenoid ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you complete the repair? | Go to Step 19 | --
16 | Replace the park/neutral position switch. Refer to Park/Neutral Position Switch Replacement in Automatic Transaxle-4T40-E/4T45-E. Did you complete the replacement? | Go to Step 19 | --
17 | Replace the automatic transmission shift lock control switch. Refer to Stop Lamp Switch Replacement in Hydraulic Brakes. Did you complete the replacement? | Go to Step 19 | --
18 | Replace the automatic transmission shift lock control solenoid. Refer to Automatic Transmission Shift Lock Actuator Replacement . Did you complete the replacement? | 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