P2421 on Volkswagen: How to Diagnose & Fix
Evaporative Emission System Vent Valve Stuck Open
1 Volkswagen model · 1 documented issue
P2421 on Volkswagen by model: symptoms, diagnosis and fix
Volkswagen bulletin 01-23-08 addresses specified fault codes on 2023 Taos vehicles with the DNKA 1.5T engine, within VIN range B2_PM000001 through B2_PM361324 and with listed ECM software. The codes are P2421, P2422, P2025, P24D6, P2B7B, P0456, P0169 and P30C0. The bulletin requires the applicable ECM update before diagnosing or replacing components for those codes.
Common Symptoms
- Check engine light / MIL on with one of the bulletin's listed EVAP fault codes stored
How to Fix
Have the dealer verify VIN, engine, stored codes and ECM software against bulletin 01-23-08 before applying its update-first procedure. Afterward, retest and diagnose any remaining symptoms using the appropriate repair information. Confirm warranty coverage separately: federal 8-year/80,000-mile coverage applies to specified major emissions components, not automatically to every EVAP valve or canister. Other manufacturer or state coverage may apply.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (1)
P2421 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P2421 mean on a Volkswagen?
P2421 stands for "Evaporative Emission System Vent Valve Stuck Open." The EVAP vent valve seals the charcoal canister so the PCM can pressurize/evacuate the EVAP system for leak testing. This generic code sets when the PCM determines the vent valve is stuck open, so the system cannot hold pressure/vacuum and leak testing fails. On Volkswagen it is documented across 1 model: Taos.
What are the most common causes of P2421?
The most common causes of P2421 are: Vent valve mechanically stuck open / debris contamination, Failed vent valve solenoid, Open control circuit holding valve de-energized, Damaged valve seat or spring. The specific cause varies by vehicle.
How much does it cost to fix P2421 on a Volkswagen?
Repair costs vary widely with the root cause and Volkswagen model; each issue on this page carries its own estimate where one is published.
Looking for P2421 on a different make?
View P2421 across all makes →Join 700+ subscribers following Au7o for vehicle insights and updates.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.