Transmission Won't Shift Out of Park
Shift lock systems prevent the shift lever from moving to (R)everse or (D)rive from (P)ark, unless the brake pedal is depressed and the accelerator is in its rest position. Most shift lock systems prevent the shift lever being shifted, when the brake pedal and accelerator are stepped on at the same time. An actuator solenoid and module assembly, located on the lower portion of the steering column, locks the shifter in Park, whenever it receives a signal that the ignition key is in the ON position. When the module receives a signal from the Brake On-Off (BOO) switch that indicates the brake pedal is depressed, it unlocks the shifter so it can be shifted out of Park. The most common failures are the fuse, which also protects the cruise control deactivation circuit, and the BOO switch. If the system is not operating, check the fuse first. If it's okay, the BOO switch may be the problem. In case of system malfunction, some shift lock systems allow the shift lever to be released by pushing a key into a release slot near the shift lever. For other systems, apply the parking brake, turn the ignition key to LOCK, then remove the key. Insert the key and turn it to OFF. Press the brake pedal. Shift to Neutral, start the vehicle, and select the desired gear. You definitely want to check out these possibilities.
1. Check all under hood and under dash fuses with a test light or multi-meter. Be thorough, since this can save a lot of time and money. Clean contacts on any fuses that don't initially pass current with abrasive cloth.
2. Verify that the brake light switch is operating properly--adjust, if necessary. Spray with WD-40 if it's hanging up. Replace, if it fails continuity.
3. Check gear shift lever adjustment.
4. Check for a faulty Automatic Transmission Gear Position Switch. These switches are relatively high-wear items, especially on older vehicles. Before replacing, though, spray with WD-40 and check adjustment.
Typical Automatic Transmission Gear Position Switch Adjustment/Replacement:
a. Remove cover and disconnect multi-pin connector from switch.
b. Remove cover switch mounting nuts.
c. Position slider switch to "Neutral."
d. Move shift lever to "Neutral," then slip switch into position.
e. Attach switch with nuts.
f. Test switch in Park and Neutral positions of shift lever. Engine should start, when shift lever is in Neutral (anywhere in the range of free play).
g. Connect multi-pin connector, clamp harness, and install console.
5. Check for a possible faulty steering lock assembly (i.e. key interlock solenoid and key interlock switch). See "Sticky," Section K.
6. Check for good contact between the connector and socket terminals.
7. Check for opens in wires and poor grounds.
Again, it's important to take a test light or multi-meter and check all under hood and under dash fuses. These fuses can affect power going to the multi-pin connector and to the interlock control unit. If the problem remains, you may want to replace the interlock control unit, which may be located on the lower portion of the steering column or near the left kick panel. These are sophisticated systems that can challenge the best technicians.