P0189Fuel Temperature Sensor B Circuit Intermittent
- 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. P0189 covers jumps or brief dropouts of sensor B, the counterpart of P0184. GM documents a gradient check for sensor A (new value outside a filtered window, 10 of 15 samples); no manufacturer using P0189 was found, so the description rests on CARB and that sensor A strategy. Loose contacts and wire breaks from vibration are the typical causes.
- What you may notice
- Check engine light on
- Jumping readings
- Likely causes
- LikelyLoose contact or weak terminal tension in the connector
- LikelyWire break or chafing from vibration
- PossibleSensor with internal dropouts
- 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: €30 – €350
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.