OBD-II code · Powertrain (generic, extended)
P25A4 Fuel Mode Select Switch Circuit
General electrical fault on the fuel mode select switch — used on bi-fuel vehicles (CNG/LPG/H2/gasoline) so the driver can pick the active fuel. With the input invalid, the ECM falls back to the default fuel and disables operator-selectable switching.
Is it safe to drive with P25A4?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen or shorted switch wire
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.3–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Fuel Mode Switch
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.