BMW 5 Series CAS4 Replacement Smart Key in Trafford, Manchester
A BMW 5 Series owner in Trafford had a smart key that had stopped doing anything: no remote locking, no unlocking and no comfort access. Autobahn diagnosed the fault and supplied and programmed a new BMW smart key on site. The car uses BMW’s CAS4 key system.
What the job record confirms
- Vehicle
- BMW 5 Series (year not stated)
- Problem
- Original key completely stopped working — no remote locking or unlocking and no comfort access (proximity) function
- Work carried out
- Fault diagnosed; brand-new BMW smart key supplied and programmed on site
- Result
- Owner back on the road with a working smart key
- Service
- Smart key replacement and programming
- Location
- Trafford
- Security / key system
- BMW CAS4 (Car Access System 4) – confirmed by Autobahn
- Equipment used
- Autel IM508S
Source: this record is taken from Autobahn’s own Instagram post of 12 August 2026.
Why the diagnosis came first
A smart key that loses every function at once can be a dead key, but the same symptoms can come from the car’s receiving side. The post records that the fault was diagnosed before a key was supplied — so the new key fixed a key fault rather than being fitted in hope.
The job was done at the vehicle, so the owner did not need to arrange recovery or a dealer booking.
This 5 Series used CAS4, BMW’s fourth-generation Car Access System, in which the key data the car checks is held in the CAS module. The new smart key was programmed to that system.
Background: BMW smart keys that stop working
The points below are general information about this kind of job. They explain the work; they are not additional details about this particular vehicle.
On BMWs with comfort access, the key talks to the car in two ways: a remote signal for the buttons, and a short-range signal the car uses to detect the key nearby for keyless entry and start. When both stop together, the key itself is the usual suspect, but a vehicle-side fault has to be ruled out.
BMW has used several key systems over the years, and the one fitted decides how a new key is programmed. That is why Autobahn asks for the registration before quoting a BMW key.
Not recorded
To keep this record accurate, the following are not published because neither the original post nor Autobahn’s job notes state them: the model year and whether the old key could be reused.
BMW key stopped working?
Send the registration and describe what the key still does, if anything. We will explain the likely cause and confirm the price.