Vehicle anti-theft systems are like the body’s immune system. They are great when they work and keep the bad guys out. They are terrible when disturbed and thwart the good. With a car, the latter scenario can happen when it doesn’t realize the owner is the right man and refuses to start or run the car, even with the factory key.
Anti-theft electronics can go haywire for a number of innocent reasons. When the car battery is replaced, the system sometimes forgets the connection to the car key. Or the anti-theft transponders in the car can communicate well with those in the key. Or maybe an actual theft attempt has triggered the immobilizer, so you’ll need to do the automatic equivalent of two-factor authorization and a Captcha to prove you’re not a thief or a robot.
If your car won’t start and you suspect it’s the car’s immobilizer, here are some tips to get the show back on the road. Our first three tips fall under the heading, “An ounce of prevention is worth a pound of cure.”
First: Google it
There are hundreds of millions of cars on the road in the US alone. Unless you’re driving a one-on-one hypercar, someone has experienced the situation you’re in and discussed it on a forum or uploaded a video of it to YouTube. Internet can be so much faster than roadside assistance. For example, the 2000 Ford F-150 responds to a combination of pressing the driver’s electric door lock button between turning the truck on and off, or using the panic button on the remote control and turning the ignition on three times to unlock the door. system reset.
Second: know your keychain
Car manufacturers pack a lot of features into key fobs, including some that may not be explained in the owner’s manual. Example: You can start a 2021 Chevy Tahoe with a key fob that does not contain a battery by placing the key fob in the cup holder on the driver’s side. You can roll up and down all the windows on a 2012 Honda Accord while out of the car if you learn the correct buttons and key placement, the same goes for a 2018 Honda Pilot.
Learn what the key fob can do and learn how to get the physical key from the fob. This also means learning where the mechanical lock is on your door and how to access it. The lock is often hidden behind a front plate to keep the door handle beautiful.
Yes, this is homework, but doing your homework is better on your couch than in a cold parking lot at 2 am
Third: keep a fob battery in the car
Any major supermarket or pharmacy sells the batteries that fit in key rings. Stick one in the glove compartment, replace it or check it every two or three years to see if it is still good. The first time you press the button, you don’t get that reassuring “click!” from the door locks you can take the spare battery and quickly rule out an easy problem.
If you’ve taken the preventative measures and the car still won’t start, here are a few strategies to get around the anti-theft devices.
Method 1: Unlock the door with the mechanical key, part 1
If the vehicle does not respond to remote control commands, remove the mechanical key from the remote control and use it to open the doors. That can let the vehicle know that the key you have has been wiped by security. Depending on the vehicle, you may be able to start the engine with the mechanical key; on some push-to-start cars, the push-button cover can be removed to reveal a traditional cylinder lock. On other vehicles you will need to locate the backup fob holder slot. The lock contains a transponder that can recognize the key.
Method 2: Unlock the door with the mechanical key, part 2
This is a more involved way of getting the car to recognize the key. Try to put the mechanical key in the door lock first, then unlock the door, lock the door and unlock the door again. Try to start the car.
If that doesn’t work, put the mechanical key in the door lock, but when you turn the key to unlock the door, hold the key for 30 seconds at the end of the turn before returning the key to neutral. Try to start the car. If this doesn’t work, get out and lock the car with the key, then repeat the unlock-and-hold method, then try to start the car.
Some vehicles require a “cheat code” for this method to work. For example, on certain Honda Accord models, it is necessary to turn the key to unlock, lock, relock and then unlock before starting, and run the car for 10 minutes to reset the theft deterrent system.
Method 3: Turn the ignition “On”
If your car has a mechanical key cylinder and it still won’t start, a flashing or steady light from the theft deterrent system may indicate the malfunction. You can try giving the car time to recognize the key again. Insert the key and turn forward two clicks to the “On” position, illuminating the dashboard, but do not attempt to start the vehicle. Leave the key there for 15 minutes; it doesn’t always take that long, but it can.
After that time, check that the anti-theft light has gone out, if one was on. Turn the key back two places to the Lock position and wait three more minutes. Once that has passed, try to start the car.
Method 4: Check the fuses
There is often a fuse associated with the immobilizer and like all fuses it can blow. Refer to the owner’s manual to locate the fuse and assess its condition. Another helpful preventative tip is to always carry a few fuses in a few amps. Fuses can be a real nuisance when they blow, and they are such easy fixes. This step is much faster than the previous method, but depending on where the correct fuse box is, you could get dirty.
Method 5: Disconnect a battery terminal
If you have the right tools (and why wouldn’t you?), disconnect one of the battery terminals to do a sort of hard reset on the electronic system. Wait a few minutes, reconnect the terminals and try to start the car.