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.
Control module function (coding/programming): Diagnosis: Notes
Faults are only entered within the voltage range 9.0 V to 15.0 V. The specified voltage corresponds to the measured value on the measuring leads of the vehicle electrical system battery. In the event of an open circuit in the measuring leads, the vehicle electrical system control module receives an 'implausible signal', which is stored in the fault memory. Only the fault 'implausible signal' is stored in the fault memory; no other faults are stored. This approach is intended to speed up fault localization. The exception to this approach is the 'Rain/light sensor' fault, which is also stored when the voltage is less than 9.0 V.
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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.