BMW has been incorporating telematics communication boxes, known as the Telematics Control Unit (TCU), Combox, or ATM (Advanced Telematic Module), in its vehicles for several years, starting with the introduction of “BMW Telematics” in 1998. Virtually all modern BMWs have a telematics module.
What does the TCB do?
The TCB is a control unit that provides the following services –
•Enhanced emergency call
•BMW Assist (information service)
•BMW Online
•BMW Mobile Office (e-mail and calendar)
•BMW AppCenter
•BMW Remote Access Service
•Manual BMW TeleServices call
•Automatic BMW TeleServices call
•BMW TeleServices diagnosis, including BMW TeleServices help
•BMW TeleServices call* Integration in Check Control message
•BMW Teleservice Report
•BMW Teleservice Battery Guard
•BMW Teleservice Update
The eSIM (electronic Subscriber Identity Module)
To connect the car to these online services, the TCB has a preinstalled eSIM (electronic Subscriber Identity Module). An eSIM is a digital SIM card that allows a device to connect to a mobile network without a physical card. The vehicle profile and the customer/owner are embedded in the eSIM and cannot be changed once downloaded, effectively making the TCB a one time use item.
The vehicle details are stored when the car is produced and the TCB has been programmed, coded and assigned to the vehicle. The customer details are installed when the connected drive/teleservices accounts are activated during vehicle handover.
TCB (Telematics Communications Box), new or used?
TCBs often fail, whether due to water ingress or an internal hardware fault. Often a subject for debate, but should you fit a used TCB in the event of a component failure?
Once both vehicle and customer details have been entered into the eSIM, they cannot be altered, which is where fitting a used TCB can pose issues.
Connected services will no longer work because the vehicle details do not match the account registered to the eSIM.
More importantly, as the vehicle details will not match, in the event of an accident severe enough to deploy the airbags, the details automatically passed on to the emergency services will be incorrect. This could result in emergency services searching for the wrong vehicle type, potentially leading to the vehicle/customer in distress being missed.
Therefore, it is advised to fit new TCBs, ordered to chassis number from BMW. A new TCB will need to be coded to the car using ISTA – the online dealer tool. In addition to coding and assigning the TCB to the vehicle, essential security certificates will be imported into the TCB, enabling full operation of all services.
Decoding (remove) the TCB (TeleCommunication BOX) module
Garages often get asked the question. Can you help me code it out – The TCB.
When the TCBs fail, an SOS warning message is displayed, alerting the driver to an issue that needs addressing.
Rather than pay for diagnosis and repair, customers often ask whether the system can be “coded out” so the annoying message is no longer displayed. A quick internet search will reveal multiple unofficial options for removing this system.
The TCB’s emergency call/eCall functionality is an important safety system. You can manually call emergency services by pressing the SOS call button. Still, more importantly, if the crash is severe enough and the airbags have been deployed, an automated call is initiated because the driver could be unconscious.
Removing/coding out this system could result in a driver and their passengers not receiving the vital assistance that they may need after a serious accident.
The consequences of this are very severe, and there is the potential for legal action to be taken against you.
If you are asked to code out the SOS system, the best advice is to decline and advise of the consequences.
The SOS call system/eCall is a legally required feature for all new cars and light commercial vans in the UK and Europe, manufactured after April 2018.