A car key that suddenly stops working rarely fails the same way twice. Sometimes the remote goes silent, sometimes the key will not turn, and sometimes it turns but the engine does nothing. Each symptom points to a different cause, and the fix is different too. This guide starts with what you are seeing and works back to the likely cause, what you can safely check yourself, and when it is time to call a mobile locksmith.
Start With the Symptom
The remote buttons do nothing
If the key still starts the car but the lock and unlock buttons are dead, the problem is almost always in the remote, not the car. The usual causes are a weak coin battery, worn button pads, or a fob that lost its connection with the car. Check the battery first, since it is the cheapest and most common fix. Our guide on why a car remote stops working walks through each cause in order.
The key goes in but will not turn
A key that slides in and then stops is usually one of three things: the steering wheel is locked against the key, the key is worn, or the lock cylinder is damaged or dirty. Do not force it, because a forced key can snap in the cylinder and turn a small problem into a bigger one. Try turning the steering wheel gently left and right while you turn the key. If that does not help, read our guide on what to do when your car key won’t turn.
The key turns, the dash lights up, but the car will not start
Most cars built in the last twenty years have a chip in the key that the car has to recognize before the engine will run. If the chip is not read, the car may crank and not start, or not crank at all, and a key or security light on the dash often stays lit or flashes. Causes include a damaged chip, a key that was copied without the chip being programmed, or a weak car battery. A key that has been cut but not programmed will open the door and still not start the car. Our article on how car keys get programmed explains why this step needs a locksmith’s equipment.
The key opens the doors but not the ignition
When the key works in the door and trunk but will not turn in the ignition, the ignition cylinder or switch is often worn. Over years of use the small parts inside wear down, and the key stops lining them up. A worn ignition can often be repaired or replaced without replacing the whole steering column. If this is happening on a Honda, see our page on Honda ignition repair.
A push-to-start car says “key not detected”
On push-to-start vehicles this message usually points to a weak fob battery or interference near the fob. Many of these cars have a backup spot, often in the cup holder, console or steering column, where you can hold the fob to start the car even with a dead battery. Your owner’s manual shows where it is on your vehicle. If swapping the battery and trying the backup spot does not help, the fob itself may need repair or replacement. Our key fob programming page covers what we can do on site.
The key is hard to insert or sticks
A key that drags going in is telling you something. Common causes are debris or lint in the lock, a bent or heavily worn key, or a cylinder that is starting to fail. A dry graphite lubricant made for locks is safer than oil-based sprays, which can attract dust and gum up the pins over time. If the key itself looks rounded or shiny along its teeth, it is worn, and the next step is replacement while it still works.
The brand new key does not work
A new key can fail for two reasons. The cut may not match the lock exactly, or the chip may not have been programmed to the car. Both are fixable. If your new key came from a hardware store or an online seller and does not start the car, it likely needs programming, and sometimes recutting. We do both on site. For a sense of what is involved, see what car key programming costs in Phoenix.
The key works only some of the time
An intermittent key is a warning. The usual causes are a worn key that only works at certain angles, a loose or dirty ignition, or a fob with a failing battery or damaged board. Intermittent problems tend to get worse, and they tend to get worse at a bad time. If you only have one key, getting a spare made now, while the original still works, is usually simpler and cheaper than waiting until it fails completely.
Quick Checks You Can Safely Try
- Try your spare key. If the spare works, the problem is the first key. If neither works, the car or lock is the likelier cause.
- Replace the fob battery. It is inexpensive and fixes a large share of remote and push-to-start complaints.
- Look at the key. Bent, cracked, or visibly worn teeth mean the key needs replacing.
- Turn the steering wheel gently. A steering lock can bind the key until you relieve the pressure.
- Check the dash. A key or security light that flashes or stays on points to the chip, not the lock.
- Check the car battery. A weak car battery can look like a key problem, with dim lights or a slow or clicking start.
What Not to Do
Do not force a key that will not turn. Do not keep using a bent key. Do not spray oil into the ignition or door lock. And do not keep driving on a key you know is failing without a spare, because a key that gives out in a parking lot leaves you stuck. A spare made from a working key costs less than starting over when no key works.
When to Call a Mobile Locksmith
If the quick checks do not solve it, a locksmith can usually diagnose the problem in a few minutes and fix it where the car is parked. That can mean cutting and programming a new key, repairing or replacing a worn ignition cylinder, repairing or replacing a fob, or programming a spare. Most car key jobs take under an hour on site. We come to you, so there is no tow and no trip to a dealership.
For car keys we ask for proof that the vehicle is yours, such as the registration or title along with your ID, because we need to be sure a key goes to the right person. Have your year, make, and model ready when you call.
Not sure what is wrong with your key? Call (602) 301-5243 and tell us what the key is doing. We serve Phoenix, Scottsdale, Tempe, Mesa, Chandler, and Glendale, and we will tell you what the job involves before we head out. You can also read about our car key replacement service.