Your car won’t start? Could be any of the standard items. The battery, the starter, the fuel pump, the ignition switch, the crankshaft position sensor, the timing belt or chain are all possible culprits. Many of those devices have electrical wires connecting them. A break in any of those wires or a poor connection will also prevent your car from lighting off.
Forget about all this stuff because I am going to add one more system to the list of possibilities. Your vehicle might be thinking you are trying to steal it. Yes, most vehicles today have some sort of anti theft system built into them. As with all things automotive sometimes they do fail.
Getting to know how your antitheft or immobilizer system works or tells you that it is working is a good idea. The source for that information is probably your owner’s manual though you may prefer “google” and/or “youtube”.
The immobilizer part of an anti theft system is what will prevent your vehicle from starting. These systems are not very standard in their behaviour and they are susceptible to intermittent failures.
When tripped these systems will prevent the starter from actually turning over, or let the starter run without starting the car. They may also let the car start but then stall. The answer for your particular vehicle again is probably in the owner’s manual.
In all cases, somewhere in the dashboard area, there is an indication of the state of the immobilizer system. Sometimes there is a flashing LED of sorts. Others will have a flashing warning light right in the instrument cluster.
The most typical system comprises a warning symbol/light right in the instrument cluster. The warning light does not have a standard picture that I know of but the behaviour is somewhat typical.
Put the right key in the ignition, turn it on and that light will come on for a few seconds and then turn off. Your car will start as usual. Use the wrong key or a bad key and the light will turn on as you turn on the ignition switch but then start flashing. The vehicle will then do whatever it does when it thinks it is being stolen.
Recognizing this scenario means you are ahead of the game. Some detective work should follow. Firstly check out your key chain. Do you have keys from more than one immobilizer equipped vehicle on your chain?
These keys have an electronic device in them. When brought in proximity to the ignition switch the key transmits a code wirelessly through an antenna ring around the key switch lock cylinder to an electronic control module that is programmed to recognize the key.
A second key on your key ring may get excited accidentally and send the wrong code to the module. Get rid of any extra keys like that on your chain and try again.
There may also be a problem with one of your keys. Hopefully you have another key for your vehicle. Get that one and try again.
If these steps fail to produce a running vehicle it is time to visit your mechanic. With the proper tools your mechanic can troubleshoot your immobilizer system.