Car doesn’t start after replacing key cylinder.

I replaced the key cylinder. I used the heavy key chain and the car started fine. Then, all of a sudden, it won't start unless I let it sit for a short period of time. It is very erratic in this behavior, sometimes going weeks with no problems, and then acting up.
Experienced mechanics share their insights in answering this question :
It sounds like you could have a faulty ignition switch. I would recommend getting a technician to test the switch to see if it is working correctly or if it needs to be replaced.

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Most vehicles will require a new key when replacing an ignition switch, as the old key has worn down and is incompatible with the new set. However, some cars may be able to use an existing key, depending on the condition and make of the key.
In either case you cannot use your key; it will be a problem since the chip is programmed to your vehicle and will require programming. You may have to replace the entire housing on the column and have the new ignition key reprogrammed to start the car.
A simple solution to getting the ignition key to turn may be as easy as checking the gear shift. In automatic cars, the ignition key won`t turn in the lock if it`s not parked or in neutral. Gently move the gear shift from side to side to check its fully in position, before trying to turn the key.
The most common reasons a Chrysler Town & Country key won`t turn are a binding steering column/lock, an ignition switch issue, or a problem with the ignition key. Search our network of RepairPal Certified shops near you to speak with a technician about your issue.
Typically, you do not need to reprogram the key fob after changing the battery. However, if you`ve replaced not just the batteries but also some of the internal wiring and electronics, you may need to reprogram it by pairing it with your vehicle once again.
The ignition relay is one of the most important electronic relays found on modern vehicles. It is usually located in the fuse and relay panel beneath the bonnet, and is responsible for providing power to the vehicle`s ignition system, and some of the fuel system`s components.
The most usual reason a transponder fails to work would be your battery. With every transponder key, there`s a little battery which aids the communication with the car. Although these batteries are made to endure for a while sometimes, they will fail and run out of juice.
Why won`t my car start but the battery is good? If your car won`t start but the battery is good, the most common cause is a faulty starter – though it could also be to do with your fuel. You may have insufficient fuel to get the car going.
The most common reasons a Chrysler 300 won`t start are a dead battery, an alternator problem, or failed starter. Search our network of RepairPal Certified shops near you to speak with a technician about your issue. How is a no-start diagnosis fixed?
You can replace the ignition switch yourself, but it`s not an easy task: you will have to remove the steering wheel and work close to the airbag – which can be dangerous. Don`t hesitate to call a professional mechanic if you`re not feeling confident.
Unfortunately, there`s no real way to start a car without the transponder chip. Although you can use a key that doesn`t have the right programming to open your vehicle`s doors, you need to use a correctly programmed key to turn ON your vehicle engine.
While it`s hard to give a universal estimate, the general cost is between $50 and $250 for reprogramming. Here`s a look at some factors that can determine price: Fob Type: Smart keys with a transponder (RFID), keyless ignition, or other extra features tend to be more expensive to reprogram.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

how to fix no keys issue if i dont have the car’s keys
ANSWER : The 2010 Maxima uses the ’Nissan Intelligent Key" system. The only way to start the car is to have the key fob in the vehicle while using the start button. There is no way to defeat this requirement as this is part of the engine immobilizer system. If the key fob is lost, one can be procured from a Nissan dealer. If somehow your vehicle was equipped with a transponder chip key (instead of the Intelligent Key system), you must have a transponder chip that is programmed specifically to your vehicle. If you need the assistance of a Mechanic, dispatched by YourMechanic right to your location, please request an electrical component diagnostic and the responding certified mechanic will assist you in obtaining a replacement key fob or transponder key. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

My car will not start Intermittently. I purchased a new battery 2 weeks ago and yesterday the car wouldn’t start. Got a jump and
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.

I put the wrong key in my car and a few weeks later my car just shut down and it will not start I believe it’s the computer but…
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

Battery and oil light come on when trying to start car, take keys out try again car starts no problem and lights go away
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.

Car cranks but won’t start
ANSWER : Hi there. It sounds like the spare key isn’t being recognized by the immobilizer system. The method you stated that you performed sounded like the procedure to manually program the wireless fob portion to lock and unlock the doors. If the key isn’t programmed or the immobilizer system has lost the registration, then it will need to be completed and this usually has to be completed by the dealer. Unfortunately, Your Mechanic does not offer key programming services. Your Mechanic does have available technicians that come to your home or office to perform requested services, inspections, and repairs. Feel free to schedule your next service at www.yourmechanic.com.

My car stutter starts, but only after driving it for a few minutes.
ANSWER : Hey there. This may also be caused by what is called the fuel pressure regulator. This is a unit that helps to maintain the fuel pressure at the proper level. When this is not working properly, the fuel pump may be pumping properly, but the fuel may not arrive at the fuel injectors at the proper psi. When this happens, this can cause a lean fuel condition which may cause the car to hesitate, misfire, or stall. If you would like to have an expert pinpoint the issue, a certified professional from YourMechanic can come to your car’s location to inspect the hard start problem and confirm which repairs are needed.

When I go to crank my car the key stays in the start position and the car is constantly trying to crank itself.
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.

Charging warning light comes on when i turn the key and try to start the car and the car want start but when someone tried to give
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.