P0188
Fuel Temperature Sensor B Circuit High Input
Fuel temperature sensor B signal exceeds maximum. Shorted to voltage, open ground or open sensor. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Signal wire shorted to voltageCommon
- Sensor open-circuitPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Fuel Temperature Sensor B
- Sensor Wiring
P0188 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.