P CODES (POWERTRAIN) P0100 - P0199 P0189

    Definition of Trouble Code P0189

    Trouble code P0189 refers to an issue with the Fuel Temperature Sensor B Circuit. This code indicates that the vehicle's Powertrain Control Module (PCM) has detected intermittent fluctuations or irregularities in the signal sent from the Fuel Temperature Sensor B to the PCM. The Fuel Temperature Sensor B is responsible for monitoring the temperature of the fuel inside the fuel tank, which is vital for maintaining efficient engine performance and preventing fuel-related issues.

    How to Diagnose Trouble Code P0189

    Diagnosing the P0189 trouble code involves a series of steps that can help identify the root cause of the problem. Before starting the diagnosis, make sure you have the appropriate tools, such as a digital multimeter, OBD-II scanner, and a repair manual specific to your vehicle make and model.

    Step 1: Scan the vehicle for codes

    Begin by using an OBD-II scanner to read and document any trouble codes and freeze frame data stored in the PCM. This information will be useful in identifying if there are any other related issues that need to be addressed.

    Step 2: Inspect the Fuel Temperature Sensor B and its wiring

    Locate the Fuel Temperature Sensor B, typically found on or near the fuel tank. Visually inspect the sensor for any signs of damage, corrosion, or loose connections. Also, check the sensor's wiring and connectors for fraying, melting, or corrosion. If any issues are found, repair or replace the affected components as necessary.

    Step 3: Test the Fuel Temperature Sensor B

    Using a digital multimeter, check the resistance of the Fuel Temperature Sensor B according to the specifications provided by the manufacturer. If the resistance is out of the specified range, replace the sensor. If the sensor tests within range, proceed to the next step.

    Step 4: Test the wiring and connectors

    With the multimeter, perform a continuity test on the wiring and connectors between the Fuel Temperature Sensor B and the PCM. If the wiring or connectors are found to be faulty, repair or replace them as necessary.

    How to Repair Trouble Code P0189

    After diagnosing the root cause of the P0189 trouble code, you can proceed with the necessary repairs. Here are some common repair options:

    1. Replace the Fuel Temperature Sensor B

    If the Fuel Temperature Sensor B was found to be faulty during diagnosis, replace the sensor to resolve the issue.

    2. Repair or replace damaged wiring or connectors

    Repair or replace any damaged or corroded wiring and connectors between the Fuel Temperature Sensor B and the PCM.

    3. Update the PCM software

    In some cases, updating the PCM software may resolve the P0189 trouble code. Check with your vehicle manufacturer for any available updates.


    Trouble code P0189 is related to intermittent issues with the Fuel Temperature Sensor B Circuit. By following the step-by-step diagnosis process and making the necessary repairs, you can resolve the problem and restore efficient engine performance. Always make sure to clear any stored trouble codes with the OBD-II scanner after completing repairs, and perform a test drive to ensure the issue has been resolved.

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