What causes my gear shift to lock in park - Cars & Trucks

If your 2007 Impala is stuck in park and the gear override silver button doesn't work, there may be a few potential problems that are causing the problem. Here are some common causes and troubleshooting solutions you can try: Brake light switch: The most common cause of this problem is a faulty brake light switch. The brake light switch is responsible for sending a signal to the shift interlock solenoid to release the shifter when the brake pedal is depressed and can prevent the shifter from releasing if the switch does not operate properly. Make sure your brake lights work by pressing on the brake pedal. If they don't work, it's probably a brake light switch issue that needs to be replaced. Shift Interlock Solenoid: The shift interlock solenoid is a mechanism that prevents the shifter from moving without pressing the brake pedal If the solenoid is faulty or a blown fuse can cause the shifter to go into park. Check the fuse connected to the shift interlock system and replace if necessary. If the fuse is good, the solenoid may need to be replaced. Shift Cable: The shift cable connects the shifter to the transmission and allows you to change gears. Damaged, loose, or misaligned cables can prevent the shifter from leaving the parking space. Inspect the shift cable for any obvious issues and make sure it is securely attached to the shifter and transmission. Shift lock control module: Some vehicles have a shift lock control module that ensures proper operation of the shift interlock system. Malfunction of this module can cause the problem. It may be necessary to use a diagnostic scan tool to check for any error codes associated with the module. Ignition switch: Faulty ignition under certain conditions

Something wrong with the shift lock system maybe. Safety system that won't allow the gear selector to move from park unless the driver is pushing the brake pedal . Do your brake light's work ? Does your caddy have floor or column shift ?
Automatic Transmission Shift Lock Control Description and Operation (Floor Shift)
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
• The automatic transmission shift lock solenoid (serviced as the automatic transmission shift lock actuator), as well as the body control module (BCM) and the engine control module (ECM).The shift lock solenoid is located within the floor shift control assembly with vehicles equipped with floor shift.
• The BCM controls the voltage supply circuit of the shift lock control solenoid. The following conditions must be before the BCM will supply voltage to the shift lock control solenoid.
The BCM controls the voltage to the shift lock control solenoid through the shift lock control solenoid controlled voltage circuit. The following conditions must be met before the BCM will supply voltage to the shift lock solenoid:
• The ignition is in the ON position.
• The ECM sends an input via GMLAN serial data to the BCM indicating the transmission is in the PARK position.
• The BCM determines the brake pedal is applied according the brake pedal position.
Since the shift lock control solenoid is permanently grounded, the BCM supplies voltage to the automatic transmission shift lock control solenoid, mechanically unlocking the shift lever allowing the driver to move the shift lever out of the PARK position as the solenoid energizes. When the brake pedal is not applied, the BCM turns the control voltage output of the shift lock control solenoid OFF, de-energizing the shift lock control solenoid. The de-energized solenoid mechanically locks the shift lever in the PARK position.
During remote start operation, the BCM will de-energize the shift lock control circuit, locking the shift lever in the PARK position.

Automatic Transmission Shift Lock Control System
The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
• The automatic transmission shift lock control solenoid
• The automatic transmission shift lock control switch
With the ignition in the ON position, voltage is supplied to automatic transmission shift lock control switch. Voltage flows through the normally closed contacts of the automatic transmission shift lock control switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded. This energizes the automatic transmission shift lock control solenoid causing the transmission shift lever to be physically locked in the PARK position. When the brake pedal is pressed the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to be move out of the PARK position.

Circuit Description
The transmission range (TR) switch is part of the park/neutral position (PNP) and back-up lamp switch assembly, which is externally mounted on the transmission manual shaft. The TR switch contains four internal switches that indicate the transmission gear range selector lever position. The powertrain control module (PCM) supplies ignition voltage to each switch circuit. As the gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. The PCM detects the selected gear range by deciphering the combination of the voltage signals. The PCM compares the actual voltage combination of the switch signals to a TR switch combination chart stored in memory.

These are all electronically controlled , yur best bet would be to take your vehicle to the dealer .

I am mechanic I really need to no more make ect. but it could be battery or the ignition switch or ignition lock n key but like I said need more information this is a guess that I told you

PRND321 Display
The instrument panel cluster (IPC) displays the selected gear position as determined by the engine control module (ECM). The IPC - instrument panel cluster receives a serial data message from the ECM indicating the gear position. The PRND321 display blanks if:
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The ECM detects a malfunction in the transmission range switch circuit.

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The IPC detects a loss of serial data communications with the ECM. The automatic transmission shift lock control system is a safety device that prevents an inadvertent shift out of PARK when the engine is running. The driver must press the brake pedal before moving the shift lever out of the PARK position. The system consists of the following components:
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The automatic transmission shift lock control solenoid

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The automatic transmission shift lock control switch

With the ignition in the ON position, voltage is supplied to automatic transmission shift lock control switch. Voltage flows through the normally closed contacts of the automatic transmission shift lock control switch to the automatic transmission shift lock control solenoid. The automatic transmission shift lock control solenoid is permanently grounded. This energizes the automatic transmission shift lock control solenoid causing the transmission shift lever to be physically locked in the PARK position. When the brake pedal is pressed the contacts in the automatic transmission shift lock control switch open, de-energizing the automatic transmission shift lock control solenoid. This allows the shift lever to be move out of the PARK position.
The transmission range (TR) switch is part of the park/neutral position (PNP) and backup lamp switch assembly, which is externally mounted on the transmission manual shaft. The TR switch contains four internal switches that indicate the transmission gear range selector lever position. The PCM supplies ignition voltage to each switch circuit. As the gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. The PCM detects the selected gear range by deciphering the combination of the voltage signals. The PCM compares the actual voltage combination of the switch signals to a TR switch combination chart stored in memory.
You need a Tech2 scan tool to diagnose this problem ! possible range sensor !

Shift lock control on this vehicle is complicated - your problem is probably a malfunctioning part in the system such as the shift lock control switch at the brake pedal, the Park relay, the shift lock relay (if equipped) or the A/T shift lock control solenoid. Take it to a dealer ...

Sounds like a part called a parking "Pawl" is hanging up. You could try to park the way they show you in driving school, with the rear of the tire against the curb when the car is facing uphill. Theory is that the tire will chock the vehicle against the curb as a bumper stop and prevent rolling backwards. This will minimize pressure on the inside of the transmission parking pawl.

You can go to aboutautomobile.com and search for "Consumer complaints" or Recalls and enter your vehicle info. Then see if others are having problems like yours.

The park shift lock needs adjustment. The solenoid that locks irt inplace maybe the cause of this

is the steering wheel locked in position?the tension from that could cause problems

Do not shift into park and move the steering wheel to lock it. It will lock itself if the vehicle is moved or someone tries to steel it. Reason is that the lock pin hsas many holes to drop into and if you lock it when you have turning pressure on in it. You will lock it with pressure on the lock pin.
Second, always set your parking brake before, not after putting it in park. Never put your front tires against a curb and put it in park without letting the vehile roll away from the curb.. An don't hang you car on a slope by putting it in park. Parking brake always befor parking gear and hands off steering wheel when placing in park. Try it, you'll like it.. forcing your shifter to come out of park can cause damage to the shifting componants. Let me know how it works for you. - Ned_