MechanicDB
Fault Family System: Powertrain (P-Codes) 5 SAE Codes

Fuel Mode Select Switch

Diagnostic & Technical Explanation
Code P25A4 (Fuel Mode Select Switch Circuit) sets when the ECM sees an open, shorted, implausible, or intermittent signal from the driver's fuel-mode select switch used on bi-fuel vehicles to choose between gasoline and the alternative fuel (CNG/LPG/E85). Causes are worn switch contacts, a corroded connector in the dash harness, or chafed wiring between the switch and the fuel-selection module.

These 5 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 5 times.

Codes in this family (5)

CodeDefinitionRepair coverage
P25A4Fuel Mode Select Switch Circuit3 ranked fixes
P25A5Fuel Mode Select Switch Performance3 ranked fixes
P25A6Fuel Mode Select Switch Circuit Low3 ranked fixes
P25A7Fuel Mode Select Switch Circuit High3 ranked fixes
P25A8Fuel Mode Select Switch Circuit Intermittent/Erratic3 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here: