BMW X5 E53 ABS, DSC and Brake Warning Lights On, and CAN Faults
Why do the X5 E53 ABS, DSC and brake lights come on at the same time?
Start with the fuses: a blown 5 A fuse lit all three lights. The DSC inactive and engine failsafe messages can also be caused by the mass air flow sensor, even if the fault code does not point directly to it.
What do the CAN ABS/DSC signal and CAN bus monitoring faults mean?
It is a fault in the CAN bus (the shared communication bus of the modules): some module is jamming it, and the transmission control does not get speed data from the ABS unit. Read the codes from all the modules on the bus, not just from the transmission control.
What is the likely fault if the ABS light, a gearbox fault and the speedometer stopping appear after a battery change?
Most likely the ABS unit's internal ground is intermittent and disturbs the CAN bus. First check the charging voltage, because too low a voltage can produce fault codes. If the unit works at times, repairing the ground may succeed; a permanently failed unit must be replaced.
What does the brake light in the instrument cluster mean when the code is zeitbegrenzte Passivschaltung?
The light relates to the brake pad wear warning, which is based partly on kilometres driven. The warning goes away only by resetting the counter, so resetting the fault code alone does not turn off the light.