CAN-Bus System
The Controller Area Network (CAN-bus) is the high-speed communication backbone connecting the E46 critical control modules.
Specifications
Section titled “Specifications”- Speed: 500 kbit/s
- Wiring: Twisted pair (CAN-H and CAN-L)
- Termination: 120-ohm resistors at each end of the bus
Connected Modules
Section titled “Connected Modules”- DME (engine management)
- EGS (automatic transmission, if equipped)
- ABS/DSC (braking and stability)
- IKE (instrument cluster)
- Steering angle sensor
Diagnosis
Section titled “Diagnosis”CAN-bus issues can cause multiple seemingly unrelated faults. Common causes:
- Corroded CAN-bus connector pins
- Chafed wiring causing short circuits
- Failed module pulling down the bus
- Measure resistance between CAN-H and CAN-L: should be ~60 ohms with all modules connected