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.
Electrical Additional Heater (Certain Markets)
The climate control module (CCM) (4/6) checks the function of the electric auxiliary heater.
The central electronic module (CEM) (4/56) transmits information regularly to the climate control module (CCM), for example, about the permitted size of the current consumption.
The climate control module (CCM) uses this information to prioritize between its loads. The climate control module (CCM) also uses the information to calculate how much output must be used to activate the electrical additional heater (9/41).
The central electronic module (CEM) receives information from the climate control module (CCM) via the CAN network.
The central electronic module (CEM) checks that the output voltage is not too great. See CURRENT LIMITATION - CENTRAL ELECTRONIC MODULE (CEM)
The power consumption of the electric auxiliary heater is regulated via a pulse-width modulated signal from the central electronic module (CEM).
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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.