Set by the manufacturer, so it means different things on different makes. 1 make in the table below.
No make in this table matches that.
Each line is that manufacturer's own meaning for C2121. They are genuinely different faults, not rewordings of one, so a meaning listed against one make says nothing about the others. If your make is not listed, we do not hold it - your manufacturer's service information is the authority.
Manufacturer code meanings from kierandrewett/obd (b56a07a), used under the MIT licence. Copyright (c) Kieran Drewett. SpareRadar is not affiliated with the dataset's authors.