P25C2
Alternative Fuel Disable Signal Circuit High
The disable feedback signal sits above its valid window. Typical cause is a short to battery on the feedback wire or a failed pull-up in the input stage.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Feedback wire shorted to a B+ supplyCommon
- Pull-up resistor in the input stage failedLess likely
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Alt Fuel Control Module
- Wiring Harness
P25C2 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.