P0186Fuel Temperature Sensor B Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Fuel temperature sensor B is an NTC thermistor: the hotter the fuel, the lower its resistance and signal voltage. On diesels it sits in the injection pump, rail or return line; on Ford petrol direct-injection engines it is built into the rail pressure sensor, and GM uses digital rail temperature sensors on its direct-injection engines. Sensor B is the second measuring point, for example GM's 6.6 litre diesel sensor 2 or a second rail. P0186 is the plausibility check of sensor B, the counterpart of P0181 – presumably a comparison with a reference sensor after a long standstill, as GM documents for sensor A (8 h, 20 °C). No manufacturer using P0186 was found; the description rests on CARB and the sensor A strategy.
- What you may notice
- Check engine light on
- Usually no change in driving
- Likely causes
- LikelySensor drifting (characteristic shifted)
- PossibleComparison sensor wrong (charge air, coolant, intake air)
- PossibleContact resistance in the connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €300
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.