Transmission Related:
* Transmission fluid issues: Low fluid level, dirty or contaminated fluid, or a fluid leak can all prevent the transmission from functioning properly.
* Transmission failure: Internal transmission problems (worn parts, broken components) are a serious issue requiring professional repair.
* Transmission slipping: The transmission may be slipping, meaning it's not engaging properly. This is often accompanied by a high RPM with little or no forward motion.
* Shift linkage/cables problem: Worn or broken shift linkage or cables can prevent the transmission from engaging the correct gear.
Engine Related:
* Engine not running or stalling: The car obviously won't move if the engine isn't running. Check the battery, alternator, and fuel system.
* Engine problems: Low compression, faulty spark plugs, or other engine issues can prevent it from producing enough power to move the car.
Brakes Related:
* Parking brake engaged: This is the most common and easily overlooked reason. Make absolutely sure the parking brake is released.
* Brake system malfunction: A stuck or malfunctioning brake caliper can also prevent the car from moving.
Other Possibilities:
* Wheel issues: A flat tire, a stuck brake caliper, or a seized wheel bearing will prevent the car from moving.
* Computer issues: A problem with the car's computer system (PCM or TCM) can prevent the transmission from engaging. This often triggers a check engine light.
* Drive shaft problems: A broken or disconnected driveshaft prevents power from reaching the wheels.
Troubleshooting Steps:
1. Check the parking brake: This is the first thing to check.
2. Check the engine: Is it running? If not, diagnose the engine problem.
3. Check the transmission fluid level: Low fluid is a common cause.
4. Listen for unusual noises: Grinding, whining, or other strange noises can indicate a transmission problem.
5. Check the check engine light: If it's on, have the car scanned for diagnostic trouble codes (DTCs).
6. Inspect the tires and wheels: Check for flat tires or other obvious obstructions.
If you're not comfortable diagnosing the problem yourself, take your car to a qualified mechanic. Attempting repairs without the proper knowledge and tools can be dangerous and potentially worsen the problem.
