P3056 on Buick
Battery Current Sensor Circuit Malfunction (Toyota/Lexus hybrid)
P3056 on Buick vehicles indicates battery current sensor circuit malfunction (toyota/lexus hybrid). Au7o has documented this code across 1 Buick model — most commonly on Regal. 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.
Common Causes of P3056
- •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)
P3056 on Buick by Model
Buick Regal(1 issue)
- Sudden Loss of Electric Power Steering Assist (Recall)2016
GM recalled certain 2016 Regals (built Aug 2015 – Feb 2016) because a defective circuit board in the electric belt-drive rack-and-pinion steering gear could cause a sudden loss of power steering assist, sharply increasing steering effort and crash risk. Owners have also reported steering jolting or locking at speed. Beyond the formal recall, electric power steering faults (e.g., P3055/P3056 'Steering Assist Reduced' messages) are reported on later Regals.
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View P3056 across all makes →Frequently Asked Questions
What does P3056 mean on Buick?▼
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. On Buick specifically, this code is documented across 1 model.
What causes P3056 on Buick vehicles?▼
Common causes on Buick: 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). Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P3056 on a Buick?▼
Repair costs vary widely depending on the root cause and specific Buick model.
Which Buick models have P3056 documented?▼
Au7o has documented P3056 on 1 Buick model: Regal.