Technical Description of OBD-II Trouble Code
The circuit for the fuel level sensor “B” is experiencing intermittent issues.
What does that mean?
This diagnostic trouble code is applicable to all engines equipped with OBDII, but it is more commonly found in certain Hyundai, Infiniti, Isuzu, Kia, Mazda, Mercedes Benz, Nissan, and Subaru vehicles.
The fuel level sensor (FLS) is typically located in the fuel tank, specifically in the top part where the fuel pump module is situated. The FLS converts the mechanical fuel level into an electrical signal for the Powertrain Control Module (PCM). The PCM then communicates this information to other controllers through the vehicle’s data communication bus.
The PCM uses the voltage signal from the FLS sensor to determine the amount of fuel in the tank, monitor fuel usage, and calculate fuel economy. This trouble code is triggered when the input voltage does not match the normal operating voltages stored in the PCM’s memory, even for a brief moment. It also checks the voltage signal from the FLS sensor during the initial Key On phase.
P2069 may be set due to mechanical issues (such as incorrect fuel level rationality or refueling the vehicle with the ignition switch on) or electrical issues (FLS sensor circuit). These factors should not be overlooked during the troubleshooting process, especially when dealing with an intermittent problem.
The troubleshooting steps may vary depending on the manufacturer, type of FLS sensor, and wire colors. Consult a vehicle-specific repair manual to determine the location of the “B” circuit.
Other related trouble codes for the fuel level sensor B circuit include:
Severity & Symptoms
The severity of the issue depends on the type of failure. Mechanical failures are more severe, while electrical failures can be compensated for by the PCM. Compensation usually results in the fuel gauge constantly reading empty or full.
Symptoms of a P2069 engine code may include:
Potential Causes
The common causes for this code to be triggered are:
Diagnostic and Repair Procedures
It is recommended to start by searching for any technical service bulletins (TSBs) related to your specific vehicle. The vehicle manufacturer may have a PCM flash/reprogram to address this issue, so it’s worth checking before proceeding with other steps.
Next, locate the Fuel Level Sensor (FLS) in your vehicle. It is usually found in the fuel tank or the top part of the fuel tank / fuel pump module. Once located, visually inspect the connector and wiring for any signs of scraping, rubbing, bare wires, burn spots, or melted plastic. Disconnect the connector and carefully examine the terminals inside for any signs of burning or corrosion. If needed, clean the terminals using electrical contact cleaner and a plastic bristle brush. Apply electrical grease to ensure proper contact.
If you have a scan tool, clear the diagnostic trouble codes from memory and check if the P2069 code returns. If it does not, then the issue was most likely related to the connections.
The fuel tank connections are the most common area of concern for this code, as they often experience corrosion issues.
If the P2069 code does return, further testing of the FLS sensor and its circuits is necessary. With the Key Off, disconnect the electrical connector at the FLS sensor. Connect a Digital Voltmeter (DVOM) black lead to the ground or low reference terminal at the FLS sensor wiring harness connector. Connect the red lead of the Digital Voltmeter to the signal terminal at the FLS sensor wiring harness connector. Turn the Key On Engine Off and check the manufacturer’s specifications. The voltmeter should read either 12 volts or 5 volts. Wiggle the connections to see if there are any changes. If the voltage is incorrect, repair the power or ground wire, or replace the PCM.
If the previous test passed, connect one lead of an ohmmeter to the signal terminal at the FLS sensor and the other lead to the ground or low reference terminal at the sensor. The ohmmeter reading should not be zero ohms or infinite. Refer to the manufacturer’s specifications for the resistance of the sensor to accurately test the resistance to fuel level. Wiggle the connector at the Fuel Level Sensor while monitoring the resistance. If the ohmmeter readings do not pass, replace the FLS.
If all previous tests have passed and the P2069 code persists, it is likely that the FLS sensor has failed. However, a failed PCM cannot be ruled out until the FLS sensor has been replaced. If unsure, seek assistance from a trained automotive diagnostician. PCMs must be programmed or calibrated to the vehicle for correct installation.
