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.
Convenient-start system
- E60, E61, E63, E64 up to 09/2005
The starter is only activated until the engine is running.
If the engine does not start, the starting procedure is aborted after approximately 30 seconds. When the engine is already running, the starter motor is prevented from starting up again (if the ignition key is turned again).
The CAS holds the rolling code for the electronic immobilizer (EWS). This rolling code is transferred between the CAS and the DME control unit or DDE control unit. The DME control unit or DDE control unit does not enable the ignition or fuel injection until a valid rolling code (authorized ignition key) is detected.
- E70, E81, E87, E90, E91, E92, E93 and E60, E61, E63, E64 from 09/2005
The starting procedure begins when the START/STOP button is pressed. The starter is only activated until the engine is running. If the engine does not start, the starting procedure is aborted after approximately 60 seconds.
Only the driver's commands are picked up by the START/STOP button. The starting procedure is controlled by the CAS control unit.
The CAS will only carry out an engine start if all start conditions have been met. If a condition ceases to be met during the starting procedure, the starting procedure will be aborted.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.
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