Troubleshooting Remote Key Won’t Unlock Car Door

A key fob is a nice convenience, but it’s frustrating when the remote key won’t unlock car door. A dead key fob means you’re locked out of the car, which is the last thing anyone would want when in a hurry.

A smart fob can stop working for several reasons and diagnosing them is quite simple. In most cases, it’s the battery that has gone bad, but there could be a couple of other problems too.

Troubleshooting of Remote Key Won’t Unlock Car Door

Before starting to diagnose the causes, you can use a backup key fob (if you have one) to see whether the problem is with the remote or the car door. If the backup remote can lock and unlock the door, you will know for sure that there’s something wrong with the main remote.

Here are the things that you can do to resolve the problem.

Swap the Battery

If the smart fob does not have any physical damage, the easiest solution to fix this issue is to change the battery. Open the battery cover and pry out the battery with something like a small screwdriver or a key. Take notes of the numbers on the battery and replace it with a similar one. If a dead battery is the source of trouble, the remote key should be working after the replacement.

Change Broken Internal Contacts

A key fob casing is mostly plastic, and it gets exposed to lots of abuse. Tho two most vulnerable components are the buttons and the battery terminal contacts. A visual inspection is enough to find out if the terminals are broken or loose. Soldering them back to their position is likely to solve the problem.

remote car key
Change the battery contacts if they are broken. (Photo Source: carkeysplus)

Buttons can also be soldered in place if they feel loose. But there is no way to fix when the buttons are snapped off or when rubber buttons don’t sit in their slots properly.

Unlock the Door Manually

If the problem occurs due to a dead battery but there is no shop around to buy a new one, hold the fob against the door’s handle and try to pull it. The battery may have a little juice left that can open the door when you keep the fob at a close distance.


Remote Unlocking of the Door

If the remote key won’t unlock car door even after battery swapping or fixing the battery contacts, try a distant unlocking service.

Most car brands offer a remote door unlock service for emergencies such as a broken smart fob and locking the keys inside the car. You will need to set these services up ahead of time. For example, the American-based car brands including Fiat, Chrysler, Jeep, and others use the Unconnect Access service for their vehicles. You have to be an Unconnect subscriber to get the Remote Vehicle Start facility. It also offers a few more services like calling roadside assistance and 9-1-1, vehicle finder, stolen vehicle assistance, and more.

Similarly, BMW, Chevrolet, Lexus, Mazda, Honda, Nissan, Jaguar, and plenty of other automakers offer this service for remote unlocking of the car door. If your car does not have any such option, which is highly unlikely, you can still call a roadside assistance service for help.

Get the Hidden Key

Vehicles have a physical key for locking and unlocking the door. If you close and open your car door with the smart fob, this key is likely to be hidden inside the fob. There should be a release button or catch in the remote, pressing which will pop out the spare key.

But some vehicles may not have a visible keyhole. Don’t worry. They have a keyhole concealed near the door’s handle. A trim piece is there with a small slot to insert the key. You may need to prise away the trim piece to access the hole. Be careful because doing so may chip off the paint or denting the trim piece.

remote key won't unlock car door
Find the hidden key in the remote. (Photo Source: mad4wheels)

When the physical key can lock or unlock the door, be sure that the mechanism of the locks is fine. There could be an electrical issue that prevents the fob from connecting to the door’s receiver sensor.

Reprogram the Smart Fob

These are mostly the reasons and troubleshooting options when a remote key won’t unlock car door. Sometimes, the remote still does not work after checking for all possible reasons. In that case, you may have to reprogram the remote so that it pairs up with the car’s receiver unit. However, this will require getting into the car and inserting the keys into the ignition.

Without kicking off the engine, turn the key to ‘run’ and ‘lock’ positions several times until you hear a chime, which means the reprogramming is successful.