Car not starting

My keyless entry doesn't work. Also, my car doesn't start, so I think the battery has drained out. No lights were left on.
Experienced mechanics share their insights in answering this question :
A healthy vehicle battery is vital for both of these systems to work. The battery should be charged and load tested to determine if it needs to be replaced. A parasitic draw test should be run to ensure the battery is not being drained down when the vehicle is not in use. Now if this situation just happened it is possible the battery dropped a cell, something a load test will find. You may want to enlist the help of mechanic, such as one from YourMechanic, who will have the necessary tools and training to diagnose the car not starting and keyless entry issues.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

The most common reasons a Mazda 3 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.
A bad battery in the key fob is most commonly the reason for a failure to send signals to the keyless entry system. If it is available, use the spare key fob to open the vehicle and start the ignition. If the spare fob is not available, use the provided key embedded in the fob to unlock the door.
What If My Key Fob Battery Dies? A dead battery in your key fob means it can`t broadcast the signal the ignition system is looking for. If your car or truck can`t detect the correct signal, then the ignition will remain locked, and you won`t be able to start your car with the fob in your pocket.
If the engine cannot be started due to a dead key battery, the engine can be started using the following procedure: Continue to depress the brake pedal firmly until the engine has completely started. Continue to depress the clutch pedal firmly until the engine has completely started.
If the car clicks when trying to start, but still won`t start, this can be caused by a weak battery, dirty battery terminals, a worn starter motor or a stuck solenoid. If might just need a jump start, but there are a few tricks to try before breaking out the jumper cables or electric jump starter.
Insert your ignition key and turn it to Accessory (or press the start button once without pushing the brake pedal). Press the Lock button on your remote car starter. Within five seconds of turning it on, turn your key back to the “off” position (or press the start button again).
Typically, a car fob battery should last between three and four years. Additionally, there are a number of signs that will tell you when your fob battery is dying. The first sign is reduced signal strength. Most modern fobs can send a signal to your vehicle from up to 50 feet away.
Can a car run without the key fob? Ans. Yes, once the car is started, the engine will run without the key fob. However, once the engine shuts down, you won`t be able to restart it without the key fob.
If the car clicks when trying to start, but still won`t start, this can be caused by a weak battery, dirty battery terminals, a worn starter motor or a stuck solenoid. If might just need a jump start, but there are a few tricks to try before breaking out the jumper cables or electric jump starter.
Some other typical reasons engines fail to start include:

Low or discharged battery. Corroded or loose battery cables. Starter motor relay failure. Ignition switch failure.

The most common reason cars don`t start is a dead or faulty battery. Even though most cars run on gasoline, they all require electrical power to function. The starter that cranks your engine to start requires an electrical signal to fire. If something`s wrong with your battery, your car engine won`t turn over.
The most common reason cars don`t start is a dead or faulty battery. Even though most cars run on gasoline, they all require electrical power to function. The starter that cranks your engine to start requires an electrical signal to fire. If something`s wrong with your battery, your car engine won`t turn over.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

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.

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Map sensor car won’t start up good ?
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.

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car hesitates when trying to start the car ,but when started then i shut car off and start again it will start right up
ANSWER : Hi there:

Sometimes when you have problems starting an engine initially it is caused by a restriction in fuel flow; caused either by clogged fuel injectors or the throttle body that needs to be cleaned. Once the fuel starts to flow and engine warms up, it’s much easier to start. However, it could also be an air filter, EGR valve or other components that causes this issue as well, which is why it’s best to have a professional mobile mechanic complete a car is hard to start inspection so they can pinpoint the source of this issue.

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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.

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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

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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.

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My car will be starting perfect and when the gas tank gets lower it will start having problems .
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.

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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.

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