P3056 on Buick: How to Diagnose & Fix
Battery Current Sensor Circuit Malfunction (Toyota/Lexus hybrid)
1 Buick model · 1 documented issue · 1 critical
P3056 on Buick by model: symptoms, diagnosis and fix
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.
Common Symptoms
- 'Steering Assist Reduced' warning message
- Sudden heavy/stiff steering
- Steering jolting or pulling to one side
- Loss of power assist at speed
How to Fix
Under recall 21510, dealers replace the electric belt-drive rack-and-pinion steering gear assembly free of charge. Non-recall failures require diagnosis of the steering rack motor/module and replacement.
Find a Buick dealer
Choose to share your location for this search, or enter an area below. Your search location is sent to Google to find dealers.
Open Buick dealer map in Google Maps ↗Call to confirm they service Buick vehicles and check your VIN, recall eligibility, parts availability, and appointment options.
Sources for this issue (1)
P3056 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P3056 mean on a 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 it is documented across 1 model: Regal.
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 on a Buick?
Repair costs vary widely with the root cause and Buick model; each issue on this page carries its own estimate where one is published.
Looking for P3056 on a different make?
View P3056 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.