Subaru WRX 2015–2021 — technical service bulletin
Bulletin 09-131-25R · NHTSA communication 11022300 · issued Aug 11, 2025
Technical service bulletin
communication type
Electrical System
component
2015–2021
model years
7
vehicle entries
Official summary
This bulletin announces the diagnostic procedures and availability of reprograming files to rectify the following Diagnostic Trouble Codes (DTCs). • P2404: EVAP System Leak Detection Pump Sense Circuit Range/Performance. • P0420: Catalyst System Efficiency Below Threshold Bank 1. (not applicable for 15-18 models)
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.