Theft light cant start car

ANSWER : Hi and thanks for contacting Your Mechanic. If sometimes your vehicle will start with the new alternator and sometimes it won’t, then there is a loose connection in your charging system. Check all of the wires to the alternator and to the battery. Make sure that the battery cables are clean and tight. Make sure that the wires to the starter are clean and tight. A loose ground to the ignition system will cause the vehicle to not crank over. Check all of the ground wires from the battery to the starter. Make sure that they are clean and tight. If you need further assistance troubleshooting your no start situation, then seek out a technician, such as one from Your Mechanic, that can assist you.

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 : 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:

If you recently replaced your battery, the issue may be caused by a malfunctioning alternator or other electrical component that comprises the charging system on your Nissan Sentra. The best way to find out which item specifically is faulty, is to have a professional mobile mechanic complete a car is hard to start inspection. This will allow the mechanic to determine the precise source of what’s going on with your Sentra and recommend or complete the right repairs.

ANSWER : Hello and thanks for contacting YourMechanic. There are 3 things that could cause the symptoms that you are currently experiencing. One is the ignition coils getting too hot and failing.

The second is the trigger to the ignition coils could be cutting out. The camshaft and crankshaft sensors are what control the trigger to the ignition coils. If one of the sensors are not responding correctly, then the trigger may get dropped by the computer. The computer would shut down the engine to prevent any problems.

The third problem that could effect this issue is a faulty neutral safety switch on the clutch. Check the harness and wires to the switch on the clutch and see if they are clean and free from corrosion. Make sure that the switch is not binding up or sticking. I recommend replacing the neutral safety switch, then retesting. If the system continues, then replace the crankshaft and camshaft sensors. If the symptoms are still present, then the computer is locking the trigger out and shutting off the engine. Then you would need to flash or replace the computer. If you would like to have an expert scope this out in person, a qualified professional from YourMechanic can diagnose the stalling issue and let you know exactly what needs repair.

ANSWER : Hello, and thank you for writing in. When multiple sensors and warning lights appear to fail, the culprit is typically electrical. You may want to start with a basic charging system test, which would include testing the battery and the alternator. This can be done at home with a voltmeter, or at your local automotive parts store. If the charging system passes, then you may want to look into the fuses and relays, as well as check your major electrical ground connections (fuse box, battery, alternator, and the wiring). While it may be an issue with the anti-theft, with the other systems having issues as well, the anti-theft is more likely having issues resulting from a power supply problem. For more help resolving the issue, contact our service department to schedule an appointment.

ANSWER : Hello, thank you for writing in. Shaking and vibrating typically comes from a misfire, or poor engine performance. A lack of oil will absolutely contribute to these symptoms and amplify them, if not cause them to begin with. You want to turn your attention to the cause of the oil leak. If external (you can see the leaking oil), then you will want to trace the leak to the component which has failed. If the leak is internal (or the engine is consuming oil), the leak will be harder to find. It will also explain the poor engine performance due to excess oil in the combustion chamber. A head gasket is one of the main components that will fail and cause these issues. It is however not common for a vehicle this age to have these kinds of problems. You will also want to scan the computer, and see what codes are triggering your check engine light. These diagnostic tools will help you determine what system(s) is to blame for the malfunction. For more diagnostic help, contact our service department to schedule an appointment.

ANSWER : Hi. There is a couple of things that could be wrong here. The battery or alternator that was just installed could be defective. Theses parts need to be tested for proper operation. There also could be a fuse, fusible link, or wiring for the battery or charging system that is blown or broken causing the battery light to come on.

The codes that you have will cause the car to shut down, run rough, or not start at all. The crankshaft sensor and camshaft sensor should be replaced. I suggest having a certified technician from YourMechanic come diagnose the charging system and check engine codes to help you proceed with correct repairs.