26.07.2026, 17:50
Dear Freesker Support, or any other expert on the radar system:
can you help on this error code C21A909 for the Radar Module -Front center (MRR)???
It appeared after a front window replacement - and since caused issues (=fully down) of front collission assitant, lane assist, traffic light status indication
DTC report after my recent FCM calibration attached: ECU resets of FCM+Hydra+MRR, finished with a deep sleep . Software versions as well (MRR doesn't show up there)
Is it rather
a) a calibration issue?
or
b) a connection issue of wires/plugs (e.g. water in a plug; or simply plug was disconnected in a repair, but not properly reconnected)?
or
c) even a module hardware failure?
or maybe something completely different?
The interesting thing is that after calibrating the FCM with Freesker tool, the front collission assistant (including braking in close situtations), the lane assist, the traffic light status indicator started working again - so I was wondering how a front collission assistant incl braking could work without the Front center radar module, i.e. I think this module does work actually.
Nevertheless, these warning symbols keep on shining, and the error code C21A909 still remains :-(
Any hint and recommendation what to do next?
Thank you so much in advance!
can you help on this error code C21A909 for the Radar Module -Front center (MRR)???
It appeared after a front window replacement - and since caused issues (=fully down) of front collission assitant, lane assist, traffic light status indication
DTC report after my recent FCM calibration attached: ECU resets of FCM+Hydra+MRR, finished with a deep sleep . Software versions as well (MRR doesn't show up there)
Is it rather
a) a calibration issue?
or
b) a connection issue of wires/plugs (e.g. water in a plug; or simply plug was disconnected in a repair, but not properly reconnected)?
or
c) even a module hardware failure?
or maybe something completely different?
The interesting thing is that after calibrating the FCM with Freesker tool, the front collission assistant (including braking in close situtations), the lane assist, the traffic light status indicator started working again - so I was wondering how a front collission assistant incl braking could work without the Front center radar module, i.e. I think this module does work actually.
Nevertheless, these warning symbols keep on shining, and the error code C21A909 still remains :-(
Any hint and recommendation what to do next?
Thank you so much in advance!