I think your tech is wrong here. It is my understanding that when the light is "on" the system is inactive. Meaning, it will not react to a crash or anything else since it doesn't make decisions when it knows something is wrong.

I would have it retested by someone who understands the system better.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician