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.
Can Bus Communication
The E46 utilizes the now familiar "twisted pair" CAN bus wiring configuration for drivetrain and instrument cluster communication interface. The MS 42.0 to GS 20 link is a dedicated CAN circuit. The MS 42.0 is the gateway for data exchange between the GS 20 and Mark 20 EI (traction control) and the instrument cluster. See Fig 1 .
CAN bus data exchange for the GS 20 includes:
- Engine Speed (input).
- Engine Temperature (input).
- Accelerator pedal position and rate of application (input).
- Engine intervention signalling (input and output).
- Shift delay for traction control and warm up phase (input).
- Active shift program (output).
- Cruise control requirements (input).
- Turn recognition (input).
- Current Range and program selection (output).
- Torque Converter lock up signalling (output).
- Transmission fault indication lamp (output).
NO RELATED
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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.