Navigating the world of BMW key fobs can be confusing, especially when you need a replacement for your E90 model. There’s a lot of misinformation floating around, leading many BMW owners to believe that getting a new key fob is an overly expensive and complicated ordeal. Let’s clarify the facts about Bmw E90 Key Fob replacement to ensure you have the correct information and can make informed decisions.
One of the most persistent myths is the exorbitant cost of a BMW key fob. Contrary to rumors of $500 replacements, the actual retail price for a new BMW E90 comfort access key fob is around $281, and you can often find it for a street price closer to $230. Non-comfort access keys are even more affordable. It’s important to note that unlike generic car keys, BMW E90 key fobs, especially those for models with CAS (Car Access System) III and above, require a specific programming process that most general automotive locksmiths are not equipped to handle.
The process of acquiring a new BMW E90 key fob is deliberately controlled for security reasons. You can only purchase a legitimate, pre-programmed key directly from a franchised BMW dealership. These keys are not programmed locally; instead, they are ordered from the BMW factory in Germany. Each key is uniquely programmed with the correct transponder ID that matches your vehicle identification number (VIN).
This system is in place because the CAS module in your BMW leaves the factory already programmed with ten unique transponder IDs. Only keys programmed with these pre-set IDs will function with your specific car. When you order a key, you must provide your VIN and proof of ownership to the BMW dealership. This allows them to access your car’s assembly records and ensure you receive a key programmed with one of the authorized transponder IDs for your vehicle.
While there are sophisticated tools and software available that can potentially access the CAS module via the OBD port to decipher stored transponder numbers and program keys accordingly, these are considered “hacker-level” tools. Reputable sources in the USA with this specific BMW CAS tooling and expertise are rare. Consequently, most locksmiths, particularly in regions like Texas, lack the capability to properly generate new, unique replacement BMW keys for E90 models and similar BMWs. While some might offer a “cloning” service of an existing working key, this isn’t the same as creating a new, uniquely identified key, meaning features like personalized memory functions may not operate as intended.
Another crucial point to understand is that you cannot simply buy a random, virgin, or used key fob and expect to program it to your BMW E90 yourself. The idea of easily “mating” or reprogramming any key to your car is a security flaw waiting to happen. If it were that simple, vehicle theft would be rampant. BMW’s secure system prevents unauthorized key programming to protect against theft.
Dealerships often state that key replacement for comfort access equipped BMWs necessitates a service visit for programming. This is only partially accurate. Upon receiving your new key from BMW (even if ordered online), it will start the car and operate the central locking system. However, the comfort access features, such as keyless entry and start, will not function fully until a minor software adjustment is made to the car.
BMW E90 models with comfort access have two designated “slots” within the CAS module specifically for comfort access keys. These correspond to the first two of the ten pre-programmed transponder IDs. These slots are assigned to the two keys that come with the car when new. If you lose a key and replace it, ideally, the lost key’s transponder number should be removed from the CAS using BMW’s ISTA-D diagnostic software. The new key’s number is then moved into one of these comfort access “slots.” This process, while technically recommended whenever a key is lost to mitigate potential theft risks, is a quick procedure achievable in minutes by anyone with ISTA-D software or through a remote coding session, often available for around $60.
Lastly, if your existing key fob internals are functional, but the housing is damaged, you can purchase replacement housings from online marketplaces like Amazon or eBay. You can then carefully transfer your circuit board into the new housing, saving on the cost of a complete key replacement.
In conclusion, when it comes to BMW E90 key fob replacement, avoid wasting time and potentially money on unproven “budget” solutions. For a reliable, secure, and fully functional replacement, your best course of action is to order a new key fob through a BMW dealership. This ensures compatibility, security, and proper function, allowing you to spend less time worrying about your keys and more time enjoying your BMW.
