Bmw Cas Module Failure Symptoms

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Here are some possible symptoms and signs that your BMW may have an CAS fault:
  • The vehicle does not start.
  • Malfunction message on the iDrive screen.
  • Key not recognized.
  • The car will turn over but not start.
  • Low or overvoltage of EWS module.

What is the BMW CAS module?

bmw cas module location under dashbaordCAS stands for the Car Access System. Two of the main functions of the BMW CAS module include:

  • enabling the vehicle to start
  • monitoring the anti-theft alarm system.

    • CAS module generates random key code every time the vehicle is started and synchronizes the code with the Engine Control Unit, which BMW calls DME or DDE.

    When a defective BMW CAS control unit is replaced, it needs to be programmed if the module is new (virgin).

    If a used BMW CAS module is installed, the Engine Computer (DME) and key need to be replaced with those from the donor car.

    List possible symptoms you may notice if the CAS module or one of its components fails.

  • Malfunction message on the iDrive screen
  • BMW does not start
  • Key not recognized
  • BMW wont start due to a bad CAS module
  • The car will turn over but not start.
  • Vehicle Will Not Start – A defective CAS module that has been damaged from water or due to low or overvoltage will prevent the vehicle from starting. Replacing the CAS module and programming is necessary to fix this problem.
  • Mismatched Key – The code in the CAS module may get out of sync with the code stored in the DME / DDE module. To fix this problem, carry out the CAS reset procedure under DDE/DME module.

    • What is the CAS module in BMW and MINI?

    CAS stands for the Car Access System. Among other things, two of the main functions of the BMW CAS module include:

  • Enabling the vehicle to start.
  • Monitoring the anti-theft alarm system.

    • CAS module generates random key code every time the vehicle is stared which it synchronizes with the Engine Control Unit, which BMW calls DME or DDE. If you have a deffective CAS module, you vehicle may show some of the symptoms below.

    The CAS serves as an antitheft alarm system and enables the start of BMW vehicles. A transponder chip is integrated in each of the vehicle keys. A ring coil is fitted about the ignition lock. The transponder chip is powered by this coil from the CAS control module. This means that no battery is necessary in the key. The power supply and data transfer take place in the same way as a transformer between the loop antenna (coil) at the ignition lock and the transponder chip. The key then sends data to the CAS control module. If these data are correct, the CAS control module enables the starter by means of a relay located in the control module and additionally sends a coded start enable signal via a interface to the DME/DDE. These procedures may result in a start delay of up to half a second.

    The value of these codes changes after every start procedure. Start enable only takes place if the code sent by the CAS control module matches with the code stored in the DME/DDE control module. The control modules are allocated only during initial programming of the DME/DDE control module. The engine control module then adopts the rolling code of the CAS control module, process called Synchronization. EWS4 Mode

    FAQ

    What is CAS control?

    The CAS control module checks the key data to ensure it is correct and only then sends an enable signal to the starter. · The CAS control module sends the random code to DME/DDE. There, the random code is checked against the saved random code; if they match, the fuel injection is released.

    What is CAS in a car?

    1. Where is the CAS located on the specific vehicle? We all know that the function of the CAS on an engine is to monitor the rotational position and speed (RPM) of the crank shaft and it affects the ignition timing, fuel injection or the injection process on a Diesel engine.