The most common problem with a car showing a key not recognized or no key is present is that the batteries in the key are low and need to be replaced. There are several reasons why a car may not recognize the key fob, also known as a Remote Keyless Entry (RKE) system. One of the most common causes is a dead or weak battery in the key fob. If the battery is low or dead, the fob cannot transmit the correct signal to the car receiver and the car will not recognize the fob.
Another common cause is a damaged or faulty key fob antenna, which is responsible for sending the key fob's signal to the car's receiver. If the antenna is damaged or broken, the car may not recognize the key fob. Interference from other electronic devices such as cell phones, laptop computers or other electronic devices that operate on the same frequency as the key fob can also interfere with the key fob's signal and prevent the car from recognizing the key fob.
In addition, a damaged or defective receiver in the car can also cause a problem; The receiver is responsible for receiving the signal from the key fob and relaying it to the car's computer. Problems with the vehicle's software or out of range can also cause the problem. It is important to have the vehicle checked by a certified technician to diagnose the problem and fix it promptly as a faulty RKE system can prevent the vehicle from starting or locking safely.
Other possible issues that trigger the keychain not recognized alert include:
- the key does not belong to the vehicle,
- the key was removed from the car,
- the key itself is broken.
If your vehicle does not recognize the key, you can use the limp home method to start the engine.
To start most cars where the key is not recognized, depress the brake pedal and then press START with the KEYFOB. If your vehicle does not start using this method, see the instructions below.
symptoms
Common alerts displayed on the dashboard:
- No Key Detected, No Key I Detected may appear on the dashboard
- Unknown key, no key character
- The wrong key, the key does not belong to the vehicle
- Change the key fob battery
- No key present
- Car does not recognize key fobs
- I-Key System Error” is displayed in the instrument cluster
What does it mean when your car says the key was not recognized?
This means the vehicle will not be able to receive a signal from a working key, which is usually caused by a low battery in the key fob. Other potential problems include using the wrong key or damaging the key, which is to be expected if the key has been exposed to water.
Reasons why a car does not recognize the key fob
The most common reasons why a car does not recognize the key fob are:
- keychain battery– The battery in your keychain is empty or very weak. Therefore, it cannot send a strong signal to the keyless entry system. The batteries in the keys need to be replaced.
- damaged key– The key itself is damaged, which can happen if you drop or wash the key.
- programming problem– The key fob is no longer programmed to the vehicle.
- weak car battery– The battery is partially discharged and can affect the function of the immobilizer module. Charge the car battery or replace it if necessary.
- immobilizer– Immobilizer failure due to a damaged circuit board, water damage or software issue. The keyless entry system may not be able to read the fob signal due to a faulty antenna or wiring.
- wrong key– You are using the fake key. Make sure you don't get the wrong keys.
- brake switch problem– Firmly depress the brake pedal. If you do not depress the brake pedal firmly enough, or if the brake pedal position switch is defective, the vehicle may not start.
- Start Knopf–The start button may be defective. For example, it may not make contact when you press it.
- interference– Wireless devices such as aftermarket alarms and speed camera detectors can transmit on the same frequency as the smart key; it can interfere with key signals received by the Body Control Module (BCM).
How do you start a car with a dead key fob?
Even if your vehicle displays a Key Not Detected error message, you can still start the engine as long as you have a key. Press the START button with the button. If that doesn't work, you need to find the right spot to insert the key and start the car.
You can start any car by putting the key in the emergency stop position, depressing the brake pedal and START. Most cars require you to press the START button with the tip of the key. On other models it may be necessary to place the key next to the steering column, center armrest, dashboard or cup holder.
How to start vehicles with a dead key fob.
Audi
Place the key next to the steering column. Then depress the brake pedal and then press START.
BMW
Hold the key next to the steering column. If the key is not recognized, press START.
Ford
Place the key next to the steering column or press the STOP button with the key fob. On Ford Focus and other models you should see a round plastic where the ignition is located. The key with theempty batteryit must be held against the steering column or placed in the center armrest compartment on newer models.
Lexus/Toyota
If your Lexus or Toyota does not start but displays an unrecognized key, use the key fob to press the START button. The car should recognize and start the engine.
Dodge und Chrysler
If your display does not recognize the key and shows that the fob is not recognized, first press the UNLOCK button on the fob. Then press the START button with the key fob.
Nissan and Infiniti
These cars have a slot to the left of the steering wheel where you put the key if it isn't recognized.
Mitsubishi
Mitsubishi has a slot under the radio where you insert the key if it isn't recognized.
Mercedes Benz
Mercedes-Benz vehicles equipped with Keyless Go may show that the key was not recognized. Remove the START button from the ignition by pulling it out. Then use the key to turn on the ignition and start the car.
Cadillac
If your Cadillac displays "No remote detected," open the center armrest and place the key fob in the compartment. Leave the key in the compartment and press the START button to start the engine.
Chevrolet/Buick/GMC
If the key is not recognized, place the key fob in the cup holder or in the armrest storage compartment and press START. There is a padlock icon in the right place, showing where to put the key.
Hyundai
If the Hyundai display key is not recognized, open the center armrest and you will see the slot. Insert the key and use START to turn on the ignition and start the car. When exiting the vehicle, press START/STOP to turn off the vehicle. Then press the keychain and pull to remove it.
let's go
If your Kia needs a push start but doesn't recognize the key, you can start the engine by pressing the key. On some models it may be necessary to press the START button twice and then hold it for 10 seconds for the engine to start.
Renault
If your Renault shows an unrecognized card, an unrecognized card can start your vehicle by inserting the key in the dashboard lock.
Most cars can be started by pressing the START button with the key fob or by placing the key fob in the designated location on the center armrest or cup holder.
Volkswagen
Place the key next to the steering column where the ignition would be and press START and the brake pedal.
Possible fixes
Troubleshooting a vehicle that doesn't recognize the key can be challenging, even for certified auto mechanics.
Things to check if your car won't start:
- Replace the key fob battery.
- Lock and unlock the car with the key fob buttons. Then start the truck; If that doesn't work, use the remote control to press the start button.
- Disconnect or turn off any backup devices (radio, alarm system, radar detector) or anything connected to the cigarette socket.
- If you have a spare key, use it to start the car. If the vehicle starts with the second key, the first key is defective or needs new batteries.
- Disconnect the battery for five minutes, then reconnect and start the engine.
- Tow the vehicle to another location and attempt to start the engine. RF signals from surrounding buildings may interfere with keyless starting.
I changed the batteries; The car still shows an unrecognized key
If you cannot manually start the engine using either of these methods, check the following:
- fuses– Check fuses and check for blown fuses. If you don't have blown fuses, try disconnecting the battery for fifteen minutes and then recommend.
- Taste– The next thing to check is the key itself. If you have a spare key, try starting the vehicle with the second key. First, make sure the key batteries are not inserted backwards. You can easily test whether the battery in the key is working by pressing the unlock button. The doors should unlock and most keys have a small red LED light that will flash.
- Transponder- If the doors unlock/lock but the key is not recognized by the vehicle, the problem could be with a small part in the key called a transponder. It can be damaged, and although the key may still unlock the car, it won't start the engine.
Major problems are often intermittent and can be very difficult to diagnose, even for car dealers or professional mechanics.
The specific problem requires further diagnosis by a mechanic. You will need to have your vehicle towed to a mechanic or car dealer for repairs.
frequently asked questions
Can you turn off the engine with a keyless ignition if the key is not recognized?
Yes. If the key is not recognized or is in the vehicle, you can press the START/STOP button and turn off the engine.
What to do if the car key doesn't work?
You remove the metal key from the keychain. All cars have a metal emergency key that can be used to unlock the driver's door. Then use the key fob to press the START button. If that doesn't work, you may need to place the key in a designated pocket on the center console or dashboard.
Why does my keyless ignition fob have a physical key? I don't see any locks.
The physical metal key inside the fob is used to manually unlock the driver's door when the car battery is dead or the fob cannot unlock the vehicle.
How far can you drive without a wireless car key?
You can drive a car without a key in the vehicle until you run out of gas or you turn off the ignition. After turning off the engine, you cannot restart it if the key is not in the car. The vehicle may beep for a few minutes to remind you that a key cannot be recognized or is not present in the vehicle.
Will a dead car battery cause my key fob to not work because I can't unlock my car door?
Yes. If the car battery is discharged, you cannot unlock the vehicle. To get into the car, pull the emergency key from the key fob. All keys have a metal blade inside that can be used to unlock the driver's door. You must open the small flap on the driver's door to access the key fob.
Why isn't my car key working?
Your car key may not work if the batteries in the fob are dead. The key may also not work if washed, dropped in water, or on the ground.
Does a key fob have to be reprogrammed after a battery change?
No, most keys do not need to be reprogrammed after changing the battery. When you start your car for the first time after changing the battery, you must start it by placing the key fob in the designated emergency start location, which on most cars is as simple as pressing the START/STOP button with the key fob .
Can you drive a car without a key being recognized?
It is generally not recommended to drive a car if the key fob or key is not recognized by the car's system. The fob or key is an important part of the car's security and starting systems and without it the car may not start or may get stuck in a certain gear or mode.
If the key fob isn't recognized, the car may not start or the transmission may be in "sleep mode" where it just idles. This can put extra strain on the engine and transmission and lead to further damage if the problem is not corrected.
additional resources
- SMART KEY NOT DETECTED / ENGINE WILL NOT START– NHTSA.gov
We hope you find the What Causes Keychain Not Recognized guide helpful. check theseTroubleshooting and repair guidesfor more help on your vehicle.
FAQs
Why is my key fob not being detected? ›
An antenna or wiring fault in the keyless entry system, software issues, a damaged circuit board, or a faulty start button are all possible culprits. Consider having the vehicle inspected for any repair needs.
What can interfere with key fob signal? ›Radio interference: Because your smart key system uses a low-power, short-range signal, it can be blocked by the much stronger radio frequencies from many different sources, including: Your cellphone sitting in the console. The Wi-Fi hotspot in your car or phone. A Wi-Fi router in a nearby building.
Can a fuse cause my key fob not to work? ›The fuse has blown for the control circuit or module of the keyless entry system. Refer to your owner's manual for the corresponding fuse, locate the fuse box, and then test the fuse. Use a test light while the fuse is in place or remove the fuse completely to do a continuity test using a multimeter.
How do I fix an unresponsive key fob? ›Check and replace the key fob battery as needed. Take the key fob apart and check for broken contacts or misaligned buttons. Reprogram your remote yourself or have a professional do it. Replace your remote if necessary.
Can a key fob lose its programming? ›No Programming
If you allow a key fob with a battery to go dead, it can lose its initial programming. This is because any key fob must be “paired” to the car it is meant to operate.
The keyless remote is actually a radio. This data stream contains command and for security, rolling codes. The remote keyless system's receiver in the car captures the RF signal, extracts it and sends the data stream to the CPU. The CPU decodes it and sends commands to the command module.
How do I improve my key fob signal? ›That's right: With many of the classic key fobs, touching the remote to your chin while pressing the button can increase the signal strength and allow you to unlock, disarm or start the vehicle.
Does battery affect key fob? ›The fob may become less responsive or unresponsive over time. It may not lock/unlock your car easily and may start losing its range. You may have to get closer for the keyless entry function to work. In cars with a push-button start, the car may not recognize a key fob when the battery is weak.
How much does AutoZone charge to program a key fob? ›AutoZone makes and programs transponder keys with no appointment necessary and at a fraction of what you will pay at a dealership, typically between $20 to $90.
Why doesn't my key fob work after replacing battery? ›If your key fob isn't working after replacing the batteries, you may need to reprogram it or check for loose buttons and broken battery terminals.
Will disconnecting battery reset key fob? ›
However, disconnecting your car's battery for a few minutes and reconnecting it may help to reset the key fob.
How do you Remagnetize a key fob? ›You remagnetize a magnet by bringing it into contact with a strong magnet. So, if you have a weakened magnet, you must carefully bring it to contact with a strong neodymium magnet. This will make your weakened magnet regain its magnetic force. That was it.
Can Low car battery cause key fob not to work? ›The majority of cars now have remote central locking, however, with a flat or dead battery this won't work and you will be forced to use the key to open the car doors. This doesn't necessarily mean that you need a new car battery. It could be that you accidentally left a light on and the battery is just flat.
Can a magnet deactivate a key fob? ›No. A common magnet is not strong enough to interfere with, impair or otherwise compromise your employees' key fobs. For example, you could hang your key fob near metal without worrying.
What controls the key fob? ›Key fobs use radio waves to communicate with a reader in the door latch that they are programmed to open. They use a system known as radio frequency identification (RFID), which operates like an electronic barcode for identification purposes.
What controls the key fob to a car? ›When a user pushes a button on a car's key fob, a short-range radio transmitter in the fob sends a distinct coded signal to a receiver unit in the car. That as a result unlocks or locks the doors. In addition, some key fobs can also be used to open the drunk or to start the engine remotely.
Why is my car key sensor not working? ›Car key sensor is not working: If the key is not working at all, it may be due to the drained battery, faulty fob, low car battery, or faulty keyless entry system (if applicable). You can try replacing the fob batteries, diagnosing the fob or towing the vehicle to a service centre to fix the issue.
Do strong magnets affect key fobs? ›A static magnetic field does not damage a vehicle key or the built-in transponder for the anti-theft device. Therefore, you can hang your car key on a magnetic board without hesitation.
How much does it cost to calibrate a key fob? ›Several factors determine the cost to reprogram a fob. While it's hard to give a universal estimate, the general cost is between $50 and $250 for reprogramming.
What are the signs of a low battery in a key fob? ›- If your key is not giving out any signal.
- If you have to press the button repeatedly before your vehicle accepts the signal.
- If your key remote is inconsistent or unreliable.
What drains a key fob battery? ›
LEAVING YOUR KEY CLOSE TO YOUR CAR
Leaving your car key in your car overnight or even on a hook near the car is not recommended. If the fob is too close to your car, it can continue to communicate with it, which could drain the battery.
Simply put, if you lose the keyfob that enables your push-button start before you try to drive in your car, then you simply won't be able to start your vehicle.
How much does it cost to replace a key fob battery? ›Key Fob Battery Replacement
Generally, these batteries cost $10 or less, though some fobs require two batteries. Battery specialist shops and dealers will often replace the battery for free since it only takes a moment or two.
replace key remotes, reprogram remotes and transponders, repair locks and ignitions, and more. home or business, we are here for you.
Can AutoZone reprogram key fobs? ›AutoZone and many of the other big box auto parts retailers do have car remotes and key fobs to sell. They come with instructions to self-program those remotes in. Some stores will help you with that programming. But the stock they have is limited.
How do I know if my car key needs to be reprogrammed? ›A car's on-board computers is accessible when it recognises the microchip inside transponder car keys, and without this the car will not open or start, which is the case sometimes when the keys unique code cannot be read. When this happens car key reprogramming is required.
Can you program a key fob without going to the dealership? ›In reality, however, while creating a new key fob, as well as programming it to work with your car, may require the assistance of a professional, a skilled locksmith can aid you with this effort without requiring you to head back to the dealership for help.
How do I resync my car key fob? ›Insert the key into the ignition, and turn it to the on position. Don't turn on the engine, only the electronics. Leave the key in this position for 10 minutes and 30 seconds, and then turn it off. Turn the key back on, and wait for additional 10 minutes and 30 seconds before turning it off again.
Do I have to reprogram my key fob after battery replacement? ›Typically, you do not need to reprogram the key fob after changing the battery. However, if you've replaced not just the batteries but also some of the internal wiring and electronics, you may need to reprogram it by pairing it with your vehicle once again.
How do I reset my car fob? ›Press the Lock button on your remote car starter. Within five seconds of turning it on, turn your key back to the "off" position (or press the start button again). Repeat the on-off cycle three more times—you'll do four in total.
Can AutoZone program a key fob? ›
AutoZone provides a variety of key fobs that work for most vehicle makes, and they will help you match and program your fob to your car. Key fobs can range from $20 to $400 depending on the vehicle and the type of fob you buy.
Why won t my key fob work after replacing battery? ›If your key fob isn't working after replacing the batteries, you may need to reprogram it or check for loose buttons and broken battery terminals.
How much does it cost to reset a key fob? ›While it's hard to give a universal estimate, the general cost is between $50 and $250 for reprogramming. Here's a look at some factors that can determine price: Fob Type: Smart keys with a transponder (RFID), keyless ignition, or other extra features tend to be more expensive to reprogram.
Can you restart a key fob? ›Remove the battery from the key fob and put it back in (unless you put in a new battery) Remove the battery cables from the vehicle, wait 30 seconds, then hook them back up (reset computer). Put the key in the ignition and turn the key to the 'ON' position.
How do you know if your key needs to be reprogrammed? ›A car's on-board computers is accessible when it recognises the microchip inside transponder car keys, and without this the car will not open or start, which is the case sometimes when the keys unique code cannot be read. When this happens car key reprogramming is required.
Can you change a key fob battery by yourself? ›Yes, you can. DIY is quick, simple, and cheap. To do this, pry apart the key fob and replace the coin battery inside with a new one.
What can deactivate a key fob? ›The first thing you want to do is take your car and any remaining keys to a dealer or your local locksmith – a locksmith is generally the more affordable option, plus they'll be able to assist you quicker. A locksmith or dealer can now delete all keys from your car's memory and only add the keys that you have on you.
Can Low Car Battery cause key fob not to work? ›The majority of cars now have remote central locking, however, with a flat or dead battery this won't work and you will be forced to use the key to open the car doors. This doesn't necessarily mean that you need a new car battery. It could be that you accidentally left a light on and the battery is just flat.