Sprinter OM654 engine warning light with P20F409 or P202E84: AdBlue leak, AdBlue injector or air in its line

Engine / equipment

OM654 2.0 diesel in the Sprinter (VS30) with 4th-generation SCR

Period mentioned

Model years 2023 and 2024 (built before 01/08/2024)

Symptoms

Engine warning light on, sometimes with an AdBlue warning, with codes P20F409 (AdBlue consumption too low) or P202E84 (fault of AdBlue metering valve 1, engine side). It happens more with frequent starts and stops.

Possible cause described

According to Mercedes-Benz XENTRY technical note LI49.20-N-079157: a leak in the AdBlue system, an internal fault of AdBlue injector no. 1 (metering valve, engine side) or an air pocket in its line. On model year 2023 and 2024 Sprinters, the design of the AdBlue line causes those air pockets; replacing the tank or the line does not fix it.

Check for the garage

The garage runs the guided tests for those codes, looks for leaks at the AdBlue tank, pump, line and injectors and checks the line does not touch the exhaust. If there is no leak and the injector passes its test, on 2023 and 2024 vans it is enough to reset the AdBlue pump learned values, run the SCR system start-up again and do a test drive of about 30 km; no parts need replacing.

Cost cited in the source

No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.

Sources from the original database