BMW CAS Car Access System Troubleshooting

The BMW CAS (Car Access System) Module is a crucial component of the car’s security system. A failure of this module can result in various symptoms, such as the key fob not working, engine start problems, central locking issues, and warning lights on the dashboard. These issues can impact not only the vehicle’s security but also the car’s daily functionality. This article will discuss the common symptoms of a BMW CAS module failure and why it is important to have it repaired as soon as possible.

What is the BMW CAS module?

CAS 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.

The CAS module generates a 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 must 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

A faulty car access system in BMW and MINI vehicles can be indicated by symptoms such as key fob not working, remote start problems, alarm activation issues, central locking problems, engine start problems, and warning lights or messages on the dashboard. These issues can lead to incorrect functioning of the car access system. They can impact the vehicle’s safety, so it is important to have the system inspected by a professional. You may notice possible symptoms if the CAS module or one of its components fails.

• Malfunction message on the iDrive screen
• Vehicle Will Not Start  – A defective CAS module 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. BMW does not start, and the key is not recognized. The car will turn over but not start.
• 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, complete the CAS reset procedure under the DDE/DME module.
• Key fob not working: If the key fob fails to unlock or lock the doors, or the engine does not start when the key is inserted, the car access system may be faulty.
• Remote start problems: If the remote start function does not work or works intermittently, it could indicate a problem with the car access system.
• Alarm activation issues: If the alarm goes off for no apparent reason or does not activate when the car is tampered with, it may indicate a faulty car access system.
• Central locking problems: If the central locking system fails to work or operates intermittently, it could indicate a fault in the car access system.
• Engine start problems: If the engine fails to start when the key is inserted or the starter motor does not engage, it may be due to a faulty car access system.
• Warning lights or messages: If warning lights or messages appear on the dashboard indicating a problem with the car access system, it is important to have it inspected by a professional.

How to read / clear BMW CAS Fault Codes

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

The YOUCANIC full system scanner will be able to read and clear fault codes from the BMW CAS control unit. 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. Plug the OBD-II scanner into the diagnostic port under the dashboard.
2. Turn on the ignition; don’t start the engine.
3. Turn on the scanner and select your BMW chassis. Next, Select the Control Units menu.
4. Select the CAS Module. Once you enter the CAS module, you can do the following.
   • Read Codes from the CAS Module
   • Clear Codes from the CAS Module
   • Perform Adaptations, Activations, Tests
   • Reset CAS Module

Where is the BMW CAS Module Located?

The BMW CAS module is located under the steering column. To remove the BMW CAS module, you must get under the dashboard on the driver’s side and 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 in a black or white box.

When replacing the BMW CAS module, it must be programmed and synchronized with the DME and car keys. You can perform This list of tests and sensor activations via the CAS module.

• Delete the 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. One good example of this is the YOUCANIC Full System Scanner. It can perform bi-directional tests and read and clear codes from the CAS module.

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 examples of codes 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 the 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

Hundreds of fault codes can be saved in the BMW CAS module. We hope you find the BMW CAS Car Access System Troubleshooting guide helpful. Check these troubleshooting and repair guides for more help on your BMW.