Answer
Jul 11, 2025 - 01:53 AM
This is a fairly common issue on older Audi models with keyless systems like yours. When both the keyless entry and push-to-start features stop working, it usually comes down to one of a few things.
The most common culprit is the battery inside the key fob itself. If the battery is weak or dead, the car won’t recognize the remote, which means it won’t unlock the doors or allow the push-button start. Replacing the coin cell battery (usually a CR2032) is a good first step.
If the fob battery doesn’t solve the issue, you’ll want to consider the fob itself. If you have a spare key, try using it. If that one works, then the original remote may be faulty. On the other hand, if neither key works, the issue likely lies inside the vehicle.
At that point, you’re probably looking at a fault with the KESSY (keyless entry/start) module or one of its supporting components — such as one of the antennas or sensors that detect the presence of the fob. These modules can fail due to age, software issues, or even water ingress (which is somewhat common under the front seats in older VAG models).
It’s also a good idea to check the car’s fuse panel for any blown fuses related to the central locking system or KESSY. A weak vehicle battery or voltage drop during cold starts can sometimes cause these modules to behave unpredictably too.
If you’ve ruled out the fob battery and checked the fuses, your next step would be scanning the car using VCDS (VAG-COM) or similar diagnostics to check for fault codes in the comfort system or KESSY module. That would give a much clearer direction before replacing parts.
I hope that helps!
