Are you having ignition problems? Does your BMW vehicle not start? If so, this could be due to an issue with your CAS immobiliser module or ECU.

BMW CAS3 (Car Access System) Immobiliser ECU Repairs, BMW ECU / DME reprogramming

The CAS immobiliser module (transponder box) serves as an antitheft alarm system and enables the start of BMW vehicles. Within each vehicle key there is an integrated transponder chip, and a coil ring which is fitted around the ignition lock. The transponder chip is powered by this coil from the CAS module, meaning that no battery is necessary within the key. When your key is inserted in to the ignition, the transponder in the key is powered via the loop antenna, and key data is sent to the CAS control module. If the key data is correct, The CAS control module sends a coded enable signal to the DME/DDE via the data link. The engine cannot be started before this signal has been transferred. The engine control module (DME/DDE) only enables engine start if a correct enable signal is received from the CAS control module.

Common faults associated with the BMW CAS3 Immobiliser module

As mentioned above, some of the issues that you may encounter if you have a problem with your BMW CAS3 module are:

  • Immobiliser Fault Codes
  • No Communication with CAS3 Module
  • Vehicle Won't Start
  • Key Not Recognised

Most workshops/dealership will advise to replace the immobiliser module or ECU module which can become very costly. However, we’ve found a way to work around this,It is now possible to repair or swap a used BMW ECU between cars

Contact The Car Key Centre