P0169
Incorrect Fuel Composition
Fuel composition (e.g. ethanol fraction on flex-fuel vehicles) outside expected range. Wrong fuel filled or sensor fault.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Wrong fuel filled (e.g. E85 in non-flex)Common
Parts involved
- Flex Fuel Sensor
P0169 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.