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.
The Controller Area Network (Can): Compatibility
The units must "speak" the same language and must be compatible with each other. A standardized communication protocol is used for this.
Signal configuration (sfg) contains the language between the units. If any module has a signal configuration which does not correspond to other units the module cannot communicate. This means that all the units must have compatible signal configuration.
To check this the central electronic module (CEM) transmits an identification number for its signal configuration over the controller area network (CAN). The other control modules receive this number and compare it with their own. If this identity does not correspond the control modules store a diagnostic trouble code (DTC). The signal configuration is occasionally modified so that the new messages are added and old messages removed.
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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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