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P0188 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.


The P0188 DTC code for fuel temperature sensor ‘B’ relates to a high level of input error. This code shall be part of OBD II, which monitors various aspects of vehicle performance, fuel system, and emissions in real time.


The OBDII system will generate P0188 when it sees that the ‘B’ circuit in the fuel temperature sensor sends out a signal indicating higher than anticipated temperatures. The fuel temperature sensor shall bear responsibility for the transmission of critical information to the engine control module (ECMN) with respect to actual fuel temperatures in the fuel tank.


The P0188 problem 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 higher fuel temperature.
  • Wiring Problems: The fuel temperature sensor’s connections and wiring may be damaged, rusted, or disconnected, which might result in elevated input readings.
  • 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 symptoms may appear in the car when the P0188 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.
  • Engine Performance Problems: Due to erroneous sensor readings, the engine may sputter while idling or have trouble starting.


An experienced mechanic or expert will carry out the following procedures to diagnose the P0188 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 a P0188 code is dependent on the condition in which you drive and your level 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 P0188 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 P0188 include P0186 (Fuel Temperature Sensor ‘B’ Circuit Range/Performance), P0187 (Fuel Temperature Sensor ‘B’ Circuit Low Input), and P0185 (Fuel Temperature Sensor ‘B’ Circuit).


The P0188 DTC code indicates a problem with the fuel temperature sensor “B” circuit, which may have an impact on vehicle performance and fuel efficiency. It is important to address the problem promptly if you notice that a check engine light has been lit or experience any problems with vehicle performance. The problem can be diagnosed and dealt with, ensuring that your vehicle functions correctly and reliably if you need help from a qualified automotive professional.

P0188 Code – What Does It Mean & How To Fix It