Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Emergency battery
The emergency battery is designed as a nickel metal hydride battery with 4.8 V and a capacity of 600 mAh. The emergency battery serves as a voltage source if the voltage supply of the vehicle for the TCB control unit basic version is interrupted due to an accident for example. In this case, an emergency call can be placed and the connection to the emergency center maintained for at least 5 minutes independent of the voltage supply in the vehicle.
The TCB control unit basic version monitors the emergency battery after every start-up as part of an internal self-test. The emergency battery has a service life of at least 5 years. If the capacity of the emergency battery is exhausted to the extent that placing an emergency call can no longer be guaranteed then this is shown by a Check Control message (emergency call system fault!). In addition, a fault code entry is stored in the TCB control unit basic version.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.