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P0187 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


A low input error of a fuel temperature sensor ‘B’ circuit is indicated by the P0187 DTC code. This code is part of OBD II, a system that monitors in real-time every aspect of the vehicle’s performance, emissions, fuel consumption, and other systems.


The OBDII system is activated by the P0187 code when it finds that a fuel temperature sensor ‘B’ circuit has sent an indication of cooler temperatures than expected. In order to provide the engine control module (ECM) with fuel temperature data from a fuel tank, the fuel temperature sensor plays an essential role.


The P0187 error code may appear for a variety of reasons, including the following:

  • Faulty Fuel Temperature Sensor: A malfunctioning or damaged fuel temperature sensor can produce inaccurate readings, indicating a lower fuel temperature.
  • Wiring Issues: Damaged, corroded, or disconnected wiring and connectors associated with the fuel temperature sensor can cause low input signals.  
  • Issues with the sensor circuit: Erroneous readings may be caused by short circuits or open circuits in the sensor circuit.
  • ECM Malfunction: The engine control module itself may malfunction in some rare circumstances, misinterpreting the sensor data and setting off the code.


The following signs and symptoms may appear in the car when the P0187 code is present:

  • Check Engine Light: The most noticeable symptom is the illumination of the Check Engine Light on the dashboard.
  • Reduced Fuel economy: A malfunctioning sensor can have a negative effect on fuel economy since the ECM uses fuel temperature information to optimize fuel supply.
  • Uneven Engine Performance: Because of erroneous sensor readings, the engine may idle unevenly or have trouble starting.


An experienced mechanic or expert will carry out the following procedures to diagnose the P0187 code:

  • OBD-II Scanner: An OBD-II scanner will be used to retrieve the trouble code and any related codes stored in the system.
  • Visual Inspection: The fuel temperature sensor, wiring, and connections will all be examined visually to look for any obvious problems.
  • Checking the Fuel Temperature Sensor: A multimeter will be used to test the sensor’s voltage and resistance to see if it is working properly.
  • Examining the wire: The technician will carefully look for corrosion or damage in the wire and connections.
  • ECM Testing: If all other parts are in working order, it could be necessary to test or reprogram the ECM.

Common mistakes

Some frequent errors to avoid throughout the diagnostic and repair procedures include:

  • Ignoring Wiring Inspection: By skipping a careful examination of the wiring and connectors, the problem’s underlying cause might be missed.
  • Replacing Components Unnecessarily: It’s essential to use a systematic process to correctly identify the defective part and prevent replacements that aren’t necessary.

How serious is this?

The severity of the P0187 code shall be determined on the basis of operating conditions and the seriousness of symptoms. While the vehicle may still be drivable, ignoring the issue could lead to reduced fuel efficiency and potential engine performance problems.

What repairs can fix the code?

repair manuals

Following diagnosis, the following fixes could be required to fix the P0187 code:

  • Replacing the Fuel Temperature Sensor: A new sensor must be installed if the old one is malfunctioning.
  • Wiring and Connector Repair or Replacement: Damaged parts will need to be repaired or replaced.
  • ECM Reprogramming or Replacement: The ECM could occasionally need to be reprogrammed or replaced.

Related codes

Other related codes that may accompany P0187 include P0186 (Fuel Temperature Sensor ‘B’ Circuit Range/Performance), P0185 (Fuel Temperature Sensor ‘B’ Circuit), and P0188 (Fuel Temperature Sensor ‘B’ Circuit High Input).


The problem with the fuel temperature sensor ‘B’ circuit is clearly indicated by the DTC code P0187. It is necessary to solve the problem immediately if this code appears, and there are symptoms such as reduced fuel efficiency or degraded engine performance. If you have an issue, seeking professional assistance from a qualified mechanic will help diagnose and resolve the problem so that your vehicle operates correctly and smoothly.

P0187 Code – What Does It Mean & How To Fix It