P0187Fuel Temperature Sensor B Circuit Low
- 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. P0187 means the signal of sensor B is below its valid range – with an analogue NTC a short to ground or very hot reading. GM's 6.6 litre diesel sets it below 0.60 V (above about 150 °C) for 5 s; GM's direct-injection petrol engines use a digital rail temperature sensor 2 and set it below a count of 145 in 50 of 62 samples, two trips – communication faults of these digital sensors have codes of their own.
- What you may notice
- Check engine light on
- Implausibly high fuel temperature in scan data
- Possibly starting problems
- Likely causes
- LikelySignal wire shorted to ground (chafing)
- LikelySensor shorted internally
- PossibleMoisture or corrosion in the connector
- RareEngine control module
- 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 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.