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How to Replace or Repair Your Car’s Key Fob

​Lost or broken devices can leave drivers with costly expenses and vulnerabilities​

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Most new cars today come with a key fob that allows drivers to enter the vehicle without putting a key in the door lock. Some even control a car’s ignition. But what happens when that fob gets lost or damaged?

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The device can be expensive to replace, so some drivers are tempted to find a cheap option online instead of turning to a dealer or a reputable automotive locksmith. But experts recommend against going that route. For one thing, it might not work, but it can also leave drivers open to scammers.

“When customers buy their own fobs after doing searches for makes and model years, they often don’t work,” says Max Wilson, owner of the the Locksmith Agency in Richmond, Virginia. “All the Honda, Toyota [and other manufacturers’ fobs] look exactly alike, but their radio frequencies are different.”

A key fob is an electronic lock that controls entry and perhaps ignition without having to use an actual key. The fob communicates with the vehicle using radio waves that align with the car’s locking mechanism. Most new cars come with two fobs, and they often have enhanced functions, like the ability to start a car remotely or lower all the windows at once.

To do its job, an automobile fob radiates a unique, low-frequency signal to a receiver unit in the car. When the unit registers that the signal is correct, it allows the driver to use the fob to unlock doors, start the car’s engine or perform other tasks.

But some car makes and models have different versions of these radio frequency numbers. That means the radio signals that connect the fob to the reader in the door of one 2021 Toyota Tundra, for example, may be different from those mated with other 2021 Toyota Tundras. In fact, a 2015 Honda CRV can have any one of 20 fob versions, Wilson says.

“Every single detail matters when you buy a new fob,” says Sam Wilson, Max’s brother, who is also a second-generation locksmith. “Think of it this way: You can’t buy one traditional key and expect it to work on every car. It’s the same with fobs. There are a lot of variables.

Fob money savers

Replacing automobile key fobs can be pricey. Costs can range from $50 to $400 per fob, and programming costs an extra $50 to $100.

Key In on These Fob Tips

If you lose or break a key fob, consider these ideas for saving yourself money and keeping your car running properly. 

Read your owner’s manual.  Some manufacturers detail a series of steps customers can take to reboot a fob if it stops working. 

• Extra equipment can make for a lengthy replacement process. If your car features specialized equipment — such as a breathalyzer — replacing the fob may involves several steps. In the case of a breathalyzer, for example, a locksmith will need a court order to remove the breathalyzer before reprogramming the fob. 

• Check your warranty or car insurance. Some include key fob replacement.

Electronic security expert Kevin Jones, owner of EZTV Plus in San Francisco, understands the dilemma surrounding high-cost key fobs. One of his friends lost both fobs to his car a year ago and had to pay over $1,000 for the replacements.

Before buying a new fob, make sure the old one really needs to be replaced. It’s possible the device may need maintenance but not replacement.

“In cases where the fob is not working, check and replace the batteries or ... have a professional check for misaligned buttons,” Jones says.

Reprogramming the remote — kind of like resetting your cell phone — is another option to try before replacement. Check with your local auto technician or an automotive locksmith for options, says Courtney Zaharia, a consultant at Superior Honda in Harvey, Louisiana.

Be sure to check whether your insurance or car warranty covers the replacement of fobs, Jones says. “Find out whether you have car warranties or your insurance covers lost keys.” This may apply to fobs as well.

Because replacing a key fob can be costly, the best thing a vehicle owner can do is keep existing fobs in good shape. Place the devices in a secure location and make sure to protect them from water, which can do damage.

Beware of scammers and thieves

Faulty fobs can leave your car’s computer more vulnerable to hacking and even fail at such basic functions as shutting off the car’s engine. Thieves have been known to tap into the signal of a fob left near a front door, hack into the car and drive away.

When you’re replacing or repairing your fob, do your homework if you’re considering an option besides the dealer. Some automotive locksmiths can replace and reprogram fobs, says Max Wilson, but it’s essential to go to a reputable locksmith.

“Verify all their [training and certification] paperwork, talk to them and find out details of jobs they’ve done. When you look at their website and online reviews, you can usually tell who is legitimate and who is not,” says Wilson.

Sam Wilson estimates it should cost $150 to $250 to have a locksmith come to you and reprogram an existing fob. “If it is much higher or lower, price-check it by calling other places,” he says. “A lot of the locksmith industry is filled with fraudulent practices. You want to find someone who won’t overcharge or do bait and switch. Ask questions.

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