Car begins to roll when the shift lever is in park had only starts in the neutral position, just rebuilt the transmission

ANSWER : The neutral start safety switch could be misaligned or a fault in the linkage and./or cable could be contributing to the problem because "Park" is not actually reached when you move the shifter. The whole mechanism from the manual lever on the transmission up to shifter will have to be inspected. The manual lever should be inspected separately inasmuch as you indicate abnormal resistance in certain gear selections. In addition, it sounds like the shift interlock may not be functioning. The recommended service to obtain a diagnosis of all of these issues is a shift linkage/interlock inspection. If you request that service, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : The issue you are having is probably due to an intermittent fault in the starter motor itself or a deficiency in the starter electrical circuit, for example a large voltage drop due to a poor ground or a high resistance connection. These issues can be readily diagnosed and resolved on a mobile basis if you request a hard starting diagnostic. If you request that diagnostic, the responding certified mechanic will get this resolved for you promptly. Based on Toyota’s Factory Service Manual, the battery should not be disconnected if the vehicle engine is running. The battery acts as a large resistive voltage sink and consequently taking the battery out of the circuit, while the alternator is still running, can create a voltage spike on the car’s electrical system which is not good for voltage sensitive components such as the engine computer. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

ANSWER : Hi there, thank you for writing in and providing a detailed description. I’d be happy to give my insight on what to do next.

I would make the same conclusion about the neutral safety switch. I think Pep Boys made the right call. I admit, I don’t like to call a part bad without being able to duplicate the problem, but anytime a customer states their car starts in neutral but not park, we replace the neutral safety switch. I can’t recall a time that this move was wrong.

The intermittent nature of your problem does’t change this diagnosis either. The same electrical connection can work one moment and not the next. Electricity works at the atomic level that we as humans can’t directly observe, which is why we have tools to do electrical testing. Your tow truck driver got it correct.

Hope this helps and best of luck! If you’d like help replacing your neutral safety switch, consider having one of our expert automotive technicians come to your home or office to do it for you.

ANSWER : First, let’s make sure about some terminology before I proceed. I will assume the motor is actually turning over. If the car is trying to start, the motor has to be turning over or it is not trying to start. This is an important distinction when diagnosing the starting system. As a technician, I go to different parts of the system based on this description.

If the key is stuck in the start position, this is a ignition lock cylinder issue and the reason the starter continues to turn the motor over. If the starter is turning but the motor is not, then the starter is likely the problem. Either that or the teeth on the flex plate are all gone. This would require removing the transmission to repair.

If the car runs intermittently, this can be a big challenge. And it also means the starting system is working. It will need to be diagnosed when it is failing. A working car cannot be diagnosed because there is nothing wrong. Where you park your car should not have any affect. It certainly could be a wiring problem. Wiring problems hide really well and can happen anywhere in the miles of wires that are in your car. Isolating the system that is failing is really important here. At the moment I am unsure which system is failing. Starter system, ignition lock cylinder and or ignition switch electrical or something with the engine control system.

When the car is failing, you need to check for spark and fuel pressure. If neither is present, this is a clue. Usually the crank sensor will do this. Does your car have a tachometer? If so, does it move at all when cranking. This is a clue whether or not the cam and or crank sensor is working. Is there a Check Engine Light on with the key on? If there is a Check Engine Light, the code or codes can be used for specific diagnosis.

All of these concerns will send you down a diagnostic path. Be sure not to confuse yourself by misinterpreting multiple system failures. If the key does stick in the start position, this would be the first problem to solve. After that, does the motor actually turn when the starter turns? After that, the question of "Why won’t it start?" is first answered by finding what the motor is lacking. Fuel, spark etc… Good luck.

If you need assistance with these checks, contact a certified mechanic who has the tools and experience needed to properly diagnose this starting issue with your car.

ANSWER : Hello. You will need to look under the vehicle where the shifter cable hooks to the transmission and look at the cable connector end for a worn out bushing. You may be able to push the shift lever on transmission into park so you can get it started. Make sure you have the wheels blocked and parking brake on so the vehicle does not roll. If you need help having this diagnosed, a certified technician from YourMechanic, can come to your car’s location to inspect the start problem and diagnose the shifting issue.

ANSWER : Hello. If your vehicle’s shifter was broken, then it will need to be replaced before the vehicle can be driven again. Once the shifter is replaced, I would also recommend taking care of the issue that is requiring you to use the key in order to shift the vehicle. It sounds like your vehicle’s shifter interlock solenoid may be bad, as the vehicle should not have trouble shifting out of park under normal circumstances.

Similar issues can also be caused by wiring problems or an issue with the stoplight switch. I would recommend having a professional technician, such as one from YourMechanic, come to your location to diagnose the cause of the stuck shifter.

ANSWER : Hello. It sounds like your transmission position sensor is failing. This sensor sends a signal to the computer to let it know what gear the vehicle is put in and allows the vehicle to start in park and neutral. It sounds like the park part has failed. It should continue to start in neutral as long as it does not fail completely. If you want to have this taken care of, consider YourMechanic, as a certified mechanic can come to you to [diagnose why it will not start in park] https://www.yourmechanic.com/services/car-is-hard-to-start-inspection

ANSWER : Your MAP sensor is an important input for your computer. It helps determine the load on the engine to calculate the correct amount of fuel to inject. It sometimes takes a few seconds for the vehicle to realize that the sensor is not producing a good signal.

At that point, it will use other methods to determine the fuel rate, such as pre-programmed fuel maps, throttle position, etc. I would suggest replacing the MAP sensor and retesting. If you would like to have it checked first, a certified technician from YourMechanic will be able to scan your vehicle and test components to determine the root cause of your starting issue before making a repair.