# e3.4 · Trane · S8V2 — Residential gas furnace fault code lookup by brand For e3.4 · Trane · S8V2, brand is Trane; model / control board is S8V2; fault code is e3.4; fault name is Open pressure switch, 2nd stage, verified against its source on 2026-08-28. - **Brand:** Trane - **Model / control board:** S8V2 - **Fault code:** e3.4 _(verified: appears in the quote below)_ - **Fault name:** Open pressure switch, 2nd stage _(verified: appears in the quote below)_ ## What the source says > e3.4 Open pressure switch, 2nd stage ## Source - https://elibrary.tranetechnologies.com/public/residential-hvac/Literature/Installation%20Operation%20and%20Maintenance/FNR-SVX003A-EN_10312025.pdf Last verified: 2026-08-28. Review by: 2028-08-27. Part of [Residential gas furnace fault code lookup by brand](https://referencesource.org/residential-furnace-fault-codes-by-brand/).