P0187
Fuel Temperature Sensor B Circuit Low
Fuel system (sensor)
Generic OBD-II
Low
What it means
P0187 means the fuel temperature sensor "B" circuit is reading below its normal voltage range — typically a short or a failed sensor. The ECM uses fuel temperature to compensate fueling for fuel density (most relevant on diesels). The effect on driving is usually minor, and the engine still starts, but the sensor or its wiring should be repaired to keep fueling accurate.
Low
Can I keep driving? Safe to drive — effects on running are usually minor; fix at your convenience, sooner on a diesel where fueling depends more on fuel temperature.
Common symptoms
What you'll notice
- Check-engine light on
- Slightly reduced fuel economy
- Occasional hesitation
- Often no noticeable change in how the car drives
Common causes
Most likely first
- Faulty fuel temperature sensor BLikely
- Short-to-ground in the sensor signal wiringCommon
- Corroded or loose sensor connectorCommon
- Less commonly, an ECM/PCM faultLess often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame data, then check the live fuel temperature value for an implausibly low reading.
- Measure the sensor's resistance against temperature specification.
- Inspect the signal wiring for a short-to-ground and check the connector.
- Replace the fuel temperature sensor if faulty, then clear and retest.
FAQ
Quick answers
Is it safe to drive with P0187?+
Yes. The fuel temperature sensor only trims fueling for fuel density, so a fault has little effect on everyday driving. Repair it at your convenience.
Can I just clear P0187?+
It returns until the sensor or wiring short is repaired. Since it's a low-circuit fault, look for a short-to-ground or a failed sensor.
Related codes
Often seen with P0187
Read & clear P0187 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX