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.
Phone Module (PHM)
The main task of the phone module (PHM) is to manage voice calls.
The control module is behind the center console.
The phone module (PHM) communicates with components which are directly connected and with other control modules and components via serial communication. The phone module (PHM) uses the MOST network to communicate with other control modules. Diagnostic communication and software downloads are via the Controller area network (CAN).
The phone module (PHM) does not have its own keypad. The keypad and display for the infotainment control module (ICM) are used to manage menus.
The control module checks activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if the control module detects an error. In certain cases the control module replaces the faulty signal with a substitute value.
Any diagnostic trouble codes (DTCs) are stored in the control module memory. This information can be read off using VIDA via the data link connector (DLC) in the car.
If the phone module (PHM) is not powered, there will be no MOST network communication. The Infotainment Control Module (ICM) will then shut down all functionality on the MOST network.
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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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