Can you keep driving?
Can you keep driving?
Stop driving if any of these apply
- !The engine stalls, will not start, or develops a sharp fuel-control problem.
- !There is a fuel leak or a strong fuel smell.
What to check first
Step-by-step checks
- 1
Free - no tools
Confirm the exact sensor layout for the vehicle before ordering any parts
- 2
Free - no tools
Inspect the connector and harness for corrosion, broken pins, or rubbing through near the tank or rail
- 3
Basic tool needed
Compare the live reading to ambient temperature or warm-engine behavior if scan data is available
- 4
Basic tool needed
If the reading is stuck very low, check the wiring before replacing the sensor
- 5
Basic tool needed
If the sensor is built into a module, check whether the signal can be separated from the module side first
If the code returns
- -If the low reading persists after connector checks, the sensor or module is more likely.
- -If the code returns after a repair, verify the reading while moving the harness gently.
- -If another fuel-system code is also present, treat the two as related rather than separate.
Background
What this code means
P0187 is a generic fuel-temperature sensor code for sensor B.
On many vehicles, this sensor is part of the fuel composition or fuel-rail signal path, so the exact hardware layout matters.
The fuel temperature reading may sit implausibly cold or drop out while the vehicle otherwise seems normal.
Diagnosis
Common causes
Open circuit
A broken wire or bad connection can make the signal fall low or disappear.
Short to ground
The signal can be pulled lower than expected.
Failed sensor
The sensor can fail low and stop reporting correctly.
Module or harness issue
Some vehicles route the reading through a larger assembly.
Avoid these mistakes
What not to do
- xDo not replace the sensor until you have confirmed whether it is separate from a module or built into the fuel unit.
- xDo not ignore wiring or connector faults near the tank, rail, or composition sensor area.
Parts
Parts that may need replacing
See also
Related OBD codes
Source notes
Generic OBD-II (SAE J1979 / ISO 15031-5). P0187 was expanded around common fuel temperature sensor B low-input faults, including open circuits, short-to-ground conditions, and sensor failures.
This guide is written as a generic multi-make reference, so bulletin history, sensor locations, and repair order can still change by manufacturer and engine family.
This is generic OBD-II guidance and should not override vehicle-specific service information. Exact diagnosis and repair steps vary by make, engine family, and model year.
Last reviewed: 2026-04-10
Reference: Open reference