P2421: owner reports and bulletins

Powertrain (generic, all makes). We haven't written the explanation for this code yet. Below is what owners and manufacturers have filed with NHTSA.

Got P2421 on your scanner? Tell the mechanic your year, make, model and any symptoms and you'll get the likely cause and what to check first. Ask about this code.

What owners report to NHTSA

3 complaints filed with NHTSA mention P2421, 3 of them since 2015, across 2 different models. The component owners most often filed it under: fuel/propulsion system.

Manufacturer service bulletins that name P2421

8 technical service bulletins and manufacturer communications filed with NHTSA mention P2421, from 1 makes. A bulletin means the manufacturer has documented a known cause or a fix procedure for that model. Examples:

  • VOLKSWAGEN ATLAS (2022, 2023), bulletin 10241205: Customer states MIL-on, P2421 stored in ECM memory Customer states MIL-on, P2402 stored in ECM memory Customer states rattle from below the vehicle Customer states MIL-on, fault P04F0 stored in ECM memory Customer states…
  • VOLKSWAGEN PASSAT (2019, 2020, 2017, 2018), bulletin 10184286: Customer states MIL-on with P0556 Customer states MIL-on with P2421 Customer states MIL-on with Misfire code Customer states clutch pedal makes noise No crank, no start Customer states seat memory inoperative Customer st…
  • VOLKSWAGEN ATLAS CROSS SPORT (2021, 2020, 2019, 2017), bulletin 10186592: Customer states MIL-on with P2421 Customer states MIL-on with Misfire code Customer states clutch pedal makes noise No crank, no start Customer states no voice output during calls / micro phone inoperative Customer state…
  • VOLKSWAGEN TIGUAN (2020, 2021, 2019, 2017), bulletin 10185678: Customer states MIL-on with P0556 Customer states MIL-on with P2421 Customer states MIL-on with Misfire code Customer states clutch pedal makes noise No crank, no start Customer states no voice output during calls / micr…

Sources: NHTSA Office of Defects Investigation complaint database and manufacturer communications file, snapshots September 2026. A complaint or bulletin that mentions a code is a report about that vehicle, not a statement that the code has one cause.