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This guide provides instructions on how to troubleshoot the BMW CAS module (Car Access System) using an OBD-II diagnostic scanner.

Table of Contents

You will learn what the CAS module does, what systems it covers, and how to read/clear codes from the BMW CAS 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:

  1. enabling the vehicle to start
  2. 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.

Symptoms of Bad CAS Module

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 won't 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.

How to read / clear CAS Fault Codes

If you are experiencing problems, a good starting point is to read fault codes from the CAS module. If any code is PRESENT, it needs to be addressed. If codes are in STORED / PAST status, they can be erased.

List of scanners that read and clear BMW CAS fault codes.

Generic OBD-II scanners will not allow you to read and clear BMW CAS fault codes. 

  1. Plugin the OBD-II scanner into the diagnostic port under the dashboard.diagnose bmw CAS fault code via obd2 port
  2. Turn on the ignition; don't start the engine.turn on bmw ignition to read CAS fault codes
  3. Turn on the scanner and select your BMW chassis. Next, Select the Control Units CAS control unit module reading codes
  4. Select the CAS Module. Once you enter the CAS module, you will be able to do the following.
    • Read Codes from CAS Module
    • Clear Codes from CAS Module
    • Perform Adaptations, Activations, Tests
    • Reset CAS Modulebmw cas module

Where is BMW CAS Module Located?

BMW CAS module is located under the steering column. To remove the BMW CAS module, you will need to get under the dashboard on the driver side remove the plastic cover under the dashboard (above the brake and gas pedal). Once you remove the panel, you will find your BMW CAS module, a black or white box.

When replacing the BMW CAS module, it needs to be programmed and synchronized with the DME and car keys.

Adaptations & Tests in the CAS Module

This is a list of tests and sensor activations that you can perform via the CAS module.

  • Delete electric steering lock fault counter
  • Reset CAS module
  • Programming
  • Remote control, battery status

TIP! Your scanner must perform bi-directional tests to carry out these adaptations and activate sensors or modules.

Live Data

In the CAS Module, you can display live data from various sensors that communicate with the CAS module.

  • Brake light switch
  • Central locking button
  • Clutch
  • Electric steering lock fault counter
  • Status of door contact switches
  • Key number

Fault Codes

Below are some examples of codes you may see stored in the BMW CAS module.

  • A082 CAS Supply terminal 30E 30L
  • A085 CAS Fault road speed signal
  • A080 CAS Output wake up line
  • 2F44 EWS preventing manipulation
  • A103 -- CAS: immobilizer bus fault (in CAS)
  • A0B2 Supply, terminal 30E
  • 4a63 BMW Fault Code "EWS Tampering or EWS Manipulation
  • CAS 14 Door Open F/R
  • CAS 15 Door Open F/L
  • CAS 16 Door Open R/L
  • CAS 17 Door Open R/R
  • CAS 18 Bonnet open
  • CAS 19 Boot open
  • CAS 21 Ignition Problem, Depress Brake to Start
  • CAS 22 Starter Problem, Engine cannot Restart
  • CAS 38 Wrong Remote Key
  • CAS 40 Press Brake to Start
  • CAS 65 Change Key, Key Battery Low
  • CAS 66 Remote Control/Key Fault
  • CAS 67 Remote Control/Key Battery Discharged
  • CAS 68 Remote Key Stationary Function Battery Low
  • CAS 186 ELV Steering Lock Fault. The engine cannot be restarted
  • CAS 187 ELV Steering Lock Active. Move Steering Wheel to Restart
  • CAS 205 Remote Key not Present
  • CAS 206 Engine Start on next Press
  • CAS 208 Comfort Access Deactivated
  • CAS 209 Remote Key in Vehicle, Locking not possible
  • CAS 217 No Remote Control
  • CAS 303 Depress Clutch to Start
  • CAS 335 Ignition Switched On
  • CAS 347 Position R/N/D Not Possible
  • CAS 348 Engage Park Before Leaving Vehicle
  • CAS 349 Engage Park Before Switching Ignition Off
  • CAS 413 Steering Column Unlocked

There are hundreds of fault codes that can be saved in the BMW CAS module.

BMW CAS Car Access System Troubleshooting This guide provides instructions on how to troubleshoot the BMW CAS module (Car Access System) using an OBD-II diagnostic scanner.