A BMW may show the key symbol on the instrument cluster, PARK light stays on and the engine won't start if the key is not being recognized. The key may have a slash, line or exclamation line on top.
This problem is because BMW is not recognizing the key which could be due to several reasons as outlined below.
If BMW yellow key warning light displays when you are driving it is because the car stopped recognizing the key in the cabin. This can be due to the key being physically removed from the car or a problem with comfort access.
- BMW will not start or turn over
- Yellow key warning light on the instrument cluster
- BMW PARK warning light on
- Car or Instrument Cluster doesn't turn on
- Key symbols come up while driving
- Defective BMW key
- Comfort access not working
- Low battery voltage
- Electrical interference
- Water in BMW keyfob
- Local radio waves
If your BMW key fob got wet because you washed it or let it out in the rain, it can fail to communicate with your BMW. Let the BMW key fob dry for a few hours and try again.
Even if the key starts to work again, you shouldn't rely on it as it may stop working at any time.
Replace Key Fob Battery
Replace the batteries in your key fob. If you have comfort access the batteries may be dead. If that is the case, your BMW will not recognize the comfort access key.
A temporary solution would be to start the car by inserting the key into the key slot, pressing the start button with the keyfob or placing the keyfob next to the steering column while pressing start.
If your BMW has Start/Stop button, you will need to hold the key next to the steering column where you see a small key symbol. Some BMW models have a slot where you can insert the key for a manual start or press the key against the Stop/Start button.
Try the Spare Key
Try another key. There is a very good chance that the BMW key fob has failed. If you have a second key, try starting the car with it. If the car starts and runs fine with the other key, then the first key fob is defective.
Check Car Battery
Check the age of the main battery on your BMW.
If the battery is over 7 years old, replace it even if you think you don't need a new battery. BMWs are very sensitive to the battery and voltage drops. A low battery can cause electrical issues including the key to not be recognized by the ignition.
Follow the guide on how to replace BMW battery. Rember to perform battery registration as outlined in the tutorial.
Read Fault Codes
If your BMW still won't start or turn on, it is time to get a diagnostic scanner and read the codes.
A generic OBD2 scanner will not help you much, but a BMW scanner will be able to read all BMW fault codes.