What Causes Key Fob Not Detected

The most common problem why a car displays a Key Not Detected or No Key Present is because the batteries inside the key are too weak and need to be replaced. There are several reasons a car may not detect 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 weak or dead, the key fob will not be able to transmit the proper signal to the car’s receiver, and the car will not detect the key fob.

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Another common cause is a damaged or malfunctioning key fob antenna, responsible for sending the signal from the key fob to the car’s receiver. If the antenna is damaged or malfunctioning, the car may not detect the key fob. Interference from other electronic devices, such as cell phones, laptops, or other electronic devices that operate on the same frequency as the key fob may also interfere with the key fob’s signal, preventing the car from detecting the key fob.

Additionally, a damaged or malfunctioning 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. Issues with the vehicle’s software or being out of range can also cause the problem. It is important to have the vehicle inspected by a certified technician to diagnose the problem and fix it promptly, as a malfunctioning RKE system can prevent the car from being able to start or be locked securely.

Other possible issues that trigger the key fob not detected warning message include:

• the key does not belong to the vehicle,
• the key has been removed from the car,
• the key itself is defective.

If your vehicle does not detect the key, you can start the engine using the emergency start method.

To start most cars that show the key not detected, press the brake pedal, then press START with the KEYFOB. If your vehicle does not start using this method, see the instructions below.

Symptoms

Common warning messages that come up on the dashboard:

• No key detected, No I-Key Detected may show up in the instrument cluster
• Key not recognized, No key signal
• The incorrect key, Key does not belong to the vehicle
• Change key fob battery
• No key available
• Car won’t detect key fob
• I-Key System Error” displayed in the instrument cluster

What does it mean when your car says key not detected?

It means the vehicle can not receive a signal from a working key, often caused by weak batteries inside the key fob. Other possible issues include the wrong key being used or the key is damaged, which is expected if the key has been exposed to water.

Reasons A Car Won’t Detect the Key Fob

The most common reasons why a car won’t detect the key fob are:

• Keyfob Battery – The battery inside your key fob is dead or too weak. Therefore, it can not send a strong signal to the keyless entry system. Key batteries will need to be replaced.
• Damaged Key – The key itself is damaged, which can happen when you drop the key or wash it.
• Programming Issue – The key fob is no longer programmed to the car.
• Weak car battery – The battery is partially discharged and can prevent the immobilizer module from working. Charge the car battery or replace it if necessary.
• Immobilizer – Immobilizer system fault due to damaged circuit board, water damage, or software issue.  The keyless entry system may not read the key fob signal because of an antenna or wiring fault.
• Wrong key – You are using the false key. Make sure you didn’t grab the wrong keys.
• Brake Switch Issue – Press hard on the brake pedal. If you are not pressing hard enough on the brake pedal or the brake pedal position switch is defective, the vehicle may not start.
• Start Button – The start button can be faulty. For example, it may not be making contact when you press it.
• Interference – Wireless devices such as aftermarket alarms and radar detectors can transmit at the same frequency as the smart key; it can interfere with the key signals received by the Body Control Module (BCM).

How do you start a car with a dead-key fob?

Even if your vehicle shows an error message key not detected, you can start the engine as long as you have a key. Press the START button with the key. If that doesn’t work, you need to find the correct location to insert the key and start the car.

You can start any car by placing the key in the emergency spot, pressing the brake pedal, and START. For most cars, you need to press the START button with the tip of the key. On other models, you may have to place the key next to the steering column, central armrest, dashboard, or cupholder.

How to start vehicles with a dead key fob.

Audi 

Place the key next to the steering column. Next, press the brake pedal, then push START.

BMW

Hold the key next to the steering column. If the key is not detected, then press START.

Ford 

Place the key next to the steering column or press the STOP button using the keyfob. On Ford Focus and other models, you should see a round plastic where the ignition is. The key with the dead battery will need to be held against the steering column, or on newer models, it needs to be placed inside the central armrest bin.

Lexus/Toyota

If your Lexus or Toyota does not start but shows a key not detected, use the keyfob to press the START button. The car should recognize, and the engine should start.

Dodge and Chrysler

If your display does not recognize the key and shows the key fob is not detected, first press UNLOCK button on the key fob. Next, press the START button with the keyfob.

Nissan and Infiniti

These cars have a slot on the left of the steering wheel where you insert the key if it is not detected.

Mitsubishi 

Mitsubishi has a slot below the radio where you insert the key if it can not be detected.

Mercedes-Benz 

Mercedes-Benz cars equipped with keyless go may display key not detected. Remove the START button from the ignition by pulling it out. Then use the key to turn the ignition and start the car.

Cadillac

If your Cadillac displays No Remote Detected, open the central armrest and place the key fob inside the compartment. Leave the key in the compartment, then press the START button to start the engine.

Chevrolet/Buick/GMC

If the key is not detected, place the keyfob in the cupholder or inside the armrest storage bin, then press START. The correct location will have a lock symbol indicating where to place the key.

Hyundai

If your Hyundai display key is not detected, open the central armrest, and you will see the slot. Insert the key, then use START to turn the ignition and start the car. When you leave the vehicle, press START/STOP to turn off the car. Then press the keyfob in, then pull to remove it.

Kia

If your Kia is required with push start but will not recognize the key, you can start the engine by pressing the key. You may have to press the START button twice on some models, then keep the START button for 10 seconds for the engine to start.

Renault

If your Renault displays a card not detected, a card not detected can start the vehicle by placing the key inside the keyhole on the dashboard.

Most cars can be started by pressing the START button with the keyfob or placing the keyfob in the designated spot in the center armrest or cupholder.

Volkswagen

Place the key next to the steering column where the ignition would be, then press START and the brake pedal.

Possible Fixes

Troubleshooting a vehicle that won’t recognize the key can be challenging, even for certified auto mechanics.

Things to check if your car won’t start:

• Replace the battery in the keyfob.
• Lock and then unlock the car using the buttons on the keyfob.  Next, start the truck; if that doesn’t work, use the fob to push the start button instead.
• Unplug or turn off any aftermarket devices (radio, alarm system, radar detector) or anything plugged into the cigarette outlet.
• If you have a spare key, use that 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 try to start the engine. RF signals from the surrounding building can interfere with the keyless start.

I replaced the batteries; the car still shows a key not detected

If you cannot manually start the engine using one of these methods, check the following:

1. Fuses – Check the fuses and if you have any blown fuses. If you do not have any blown fuses, try disconnecting the battery for fifteen minutes, then recommend it.
2. Key – The next thing to check is the key itself. If you have a spare key, try starting the vehicle with the second key.  Start by ensuring the batteries in the key are not installed upside down. You can easily test if the key battery works by pressing unlock button. Doors should unlock, and most keys have a small red LED light that blinks.
3. Transponder – If the doors unlock/ lock, but the key can not be recognized by the car, the problem can be a small piece inside the key, known as a transponder. It can be damaged, and even though the key can still unlock the car, it won’t start the engine.

Key problems are usually intermittent and can be very difficult to diagnose, even by vehicle dealerships or professional mechanics.

The specific problem will require further diagnosis by a mechanic. You must have your vehicle towed to a mechanic or car dealer for repairs.

Frequently Asked Questions

Additional Resources

1. INTELLIGENT KEY NOT DETECTED / ENGINE WILL NOT START  – NHTSA.gov

We hope you find the What Causes Key Fob Not Detected guide helpful. Check these troubleshooting and repair guides for more help on your vehicle.