Fuel Level Sensor B Circuit High
Diagnostic trouble code P2068 indicates that the powertrain control module (PCM) has detected a voltage signal from the secondary fuel level sensor (Sensor B) that is higher than the manufacturer's specified maximum parameter. This typically means the sensor circuit is open or shorted to voltage, preventing the PCM from accurately determining the fuel level in that portion of the tank.
This code is generally a low severity issue as it does not affect the engine's drivability or safety. However, because the fuel gauge may read incorrectly, the driver risks running out of fuel unexpectedly.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Erratic or inaccurate fuel gauge readings
- Fuel gauge always reads full
- Fuel gauge always reads empty
- Vehicle runs out of fuel despite the gauge showing fuel available
Likely causes
- Faulty fuel level sensor B (sending unit)
- Open circuit in the fuel level sensor B wiring
- Short to voltage in the fuel level sensor B circuit
- Corroded or damaged electrical connector at the fuel pump module
- Mechanical failure of the fuel level sensor float arm
- Faulty Powertrain Control Module (PCM) or instrument cluster (rare)
What to check before replacing parts
Scan for codes and monitor the fuel level sensor B data PID with a scan tool.
Look for: Check if the voltage or percentage reading is stuck at a maximum value regardless of the actual fuel level in the tank.
Inspect the wiring harness and connectors leading to the fuel tank/pump module.
Look for: Look for broken wires, chafing, corrosion, or loose pins that could cause an open circuit or short to voltage.
Disconnect the fuel level sensor B connector and test for reference voltage and ground.
Look for: A multimeter should show the correct reference voltage (usually 5V) and a solid ground. If voltage is present on the signal wire when disconnected, there is a short to voltage in the harness.
Perform a sweep test on the fuel level sensor B using a multimeter.
Look for: Measure the resistance across the sensor terminals while manually moving the float arm (if accessible). The resistance should change smoothly without dropouts or infinite readings.
Bypass the sensor by jumping the signal and ground wires at the connector (if applicable to the system design).
Look for: Observe the scan tool data or fuel gauge; if the reading drops to zero or empty, the wiring and PCM are likely good, indicating a failed sensor.
This page explains the generic P2068 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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