If you own a 2011 Smart Fortwo (or Forfour), you’ve probably seen the dreaded “TAN required” message when trying to program a new key, disable the speed limiter, or reset the radio. You might have searched for a — and landed here.

If you have a legitimate TAN but the car rejects it, consider:

2011 Smart Fortwo , a TAN code calculator is a specialized diagnostic tool used to generate 12-digit authorization codes required by the Mercedes-Benz DAS (Diagnosis Assistance System)

Unlocking dealer-only options like Cruise Control (Tempomat) , paddle shifters (steering wheel gearshift), or Softouch (automatic gear shifting mode).

: Sometimes, the paint code is noted in the owner's manual.

Synchronizing a new or used SAM (Signal Acquisition Compilation) unit or ECU to the car.