Brand new car has problem starting 2016 Nissan Sentra

ANSWER : Hi – the "hard start when hot" sounds like a weak starter solenoid – unusual for a new car. "Heat soak" the transfer of heat after a vehicle has been driven, can sometimes cause weak electrical components, like the starter solenoid, to fail while hot, but work properly once they have cooled down. Since your vehicle is under warranty, I would seek correction through the dealer where you purchased the vehicle. If this is not satisfactory, call Nissan Customer Service to escalate.

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 : 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.

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 : Based on the information you gave, it sounds like a possible fuel starvation issue, caused by a partially blocked, in-tank fuel filter or a crack in the fuel pump housing. The remedy would be to replace the fuel pump assembly and filter. The overheating may be caused by several things, including a stuck thermostat, faulty water pump, or even a cracked head gasket. I suggest having a certified technician, like one from YourMechanic, inspect the relevant systems to pinpoint the cause of your vehicle’s hard starting issue and overheating problem.

ANSWER : Of course, don’t switch gears without being fully stopped, unless your Owner’s Manual or the manufacturer has alternative advice. However, the gear shift issue has no relation to the no-start problem you are describing. Inasmuch as you only have 6,000 miles on the car, the "constant on and off" that you believe has occurred is meaningless in comparison to the expected total vehicle service life. That is, assume what you perceive as "constant on and off", during merely 6,000 miles, might be equivalent to using the car "normally" for three years. A new car should be trouble free for at least 5 years, unless there is a defect, so your "constant on and off" is not a causal factor for any fault on the vehicle. What you might have is a defect in the ignition switch, or perhaps the immobilizer system, but if the problem is not in the switch itself, clearly there is an electrical problem.

If your vehicle is under warranty, by law the dealer MUST repair the issue you are describing within a prescribed time frame and number of "attempts", otherwise the dealer will run afoul of Federal and state Lemon Laws that give you very specific rights, and recourse (contact an Attorney; we are Mechanics, NOT attorneys). Consequently, if the vehicle is still under warranty, to save yourself money do be sure to seek a resolution from the dealer. If the vehicle is not under warranty, obviously a certified Mechanic from YourMechanic could identify the electrical fault and resolve this for you. If you want to go that route, please simply request a no start diagnostic -electrical system and 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 : Hi there. What had happened is the wrong key set the security to the vehicle. This is to prevent the vehicle from starting with the wrong keys. Try removing the battery cables (+) and (-) for 13 minutes. During that time, put the original key in the ignition and turn it on. Activate everything in the car even though there is no power. Then remove the key and hook up the battery cables. The computer should have reset and reset the security. If the security is still being tripped, then I recommend seeking out a professional, such as one from Your Mechanic, to help you

ANSWER : Hi there. Check the spark plugs and see if they are worn or burned. If the plugs are good and they have a good spark, then the engine compression could be low causing a no start situation. If the spark plugs are not emitting a spark, then the crankshaft position sensor could have failed or disconnected. Check the crankshaft position sensor wiring harness and make sure that its plugged in. Check the sensor and make sure that its not broken or damaged. If you need further assistance with your engine not starting, then seek out a professional, such as one from Your Mechanic, to help you.