P3056 on 2016 Buick Regal — Battery Current Sensor Circuit Malfunction (Toyota/Lexus hybrid)
1 vehicles · 1 makes
Most Reported On
P3056 is an OBD-II diagnostic trouble code meaning “Battery Current Sensor Circuit Malfunction (Toyota/Lexus hybrid).” P3056 is a manufacturer-specific code, and its dominant usage is on Toyota and Lexus hybrids, where it means Battery Current Sensor Circuit Malfunction. A current sensor mounted on the negative cable of the high-voltage hybrid battery pack measures the amperage flowing in and out of the pack, and the battery ECU uses that 0-5V signal to calculate the battery's state of charge. The code sets when the sensor's signal fails a range or rationality check, turning on the check engine/hybrid warning light; per Toyota's fail-safe chart the car still enters READY mode and drives normally, so you may notice nothing beyond the warning light or slightly erratic charge behavior. Ignoring it leaves the hybrid system unable to accurately track battery charge, which can mean reduced fuel economy, unpredictable charge/discharge behavior, and accelerated wear on an expensive HV battery pack. Note that the same code number means something different on other makes — on GM vehicles with stop/start it is DC/DC Converter Actuator Voltage 2 Performance, and some Volkswagens use it for an exhaust gas pressure sensor circuit fault — so always confirm against your specific make. This code is most commonly reported on 2016 Buick Regal.
Common Causes
Diagnostic Tools
To diagnose P3056, you'll need an OBD-II scanner. Here are our recommendations at every price point.
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FAQ
What does P3056 mean?
P3056 stands for "Battery Current Sensor Circuit Malfunction (Toyota/Lexus hybrid)." P3056 is a manufacturer-specific code, and its dominant usage is on Toyota and Lexus hybrids, where it means Battery Current Sensor Circuit Malfunction. A current sensor mounted on the negative cable of the high-voltage hybrid battery pack measures the amperage flowing in and out of the pack, and the battery ECU uses that 0-5V signal to calculate the battery's state of charge. The code sets when the sensor's signal fails a range or rationality check, turning on the check engine/hybrid warning light; per Toyota's fail-safe chart the car still enters READY mode and drives normally, so you may notice nothing beyond the warning light or slightly erratic charge behavior. Ignoring it leaves the hybrid system unable to accurately track battery charge, which can mean reduced fuel economy, unpredictable charge/discharge behavior, and accelerated wear on an expensive HV battery pack. Note that the same code number means something different on other makes — on GM vehicles with stop/start it is DC/DC Converter Actuator Voltage 2 Performance, and some Volkswagens use it for an exhaust gas pressure sensor circuit fault — so always confirm against your specific make.
What are the most common causes of P3056?
The most common causes of P3056 are: Failed HV battery current sensor on the negative cable of the hybrid battery pack (most common Toyota/Lexus fix), Damaged, open, or shorted wiring in the battery current sensor circuit inside the HV battery assembly harness, Loose, corroded, or poorly seated battery current sensor or battery ECU connector terminals, Faulty battery ECU (hybrid battery energy control module), On GM stop/start vehicles: weak 12V battery, poor ground connections, or a failing DC/DC converter (different definition of the same code). The specific cause varies by vehicle.
How much does it cost to fix P3056?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by P3056?
Au7o has documented P3056 across 1 vehicle models from 1 manufacturers: Buick.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.