P0B43: Hybrid/EV Battery Voltage Sense B Circuit High

P0B43 sets when cell voltage channel B reads higher than a lithium-ion cell can physically reach in service, so the controller blames the measurement path. GM documents the criteria for its battery energy control module: cell voltage B at 4.8 V or above for 1.4 s within a 2 s window, Type A, one trip, with open sense line, communication and balancing faults ruled out first. Beyond GM, no manufacturer documents P0B43 publicly; FCA's sister code P0B3E for channel A shows that software in the battery controller can cause such readings. CARB treats battery voltage sensors as monitored input components. Overcharged cells use separate cell voltage codes. Low, range and open faults of channel B are P0B42, P0B41 and P0B40.

High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

Symptoms

MIL and hybrid warning on
Charging or electric drive limited

Most likely causes

Open sense line letting the input float high
Battery controller software misreading the channel
Measurement input of the cell monitoring chip failed

What to check, in order

Start with the simplest. You can tick off each step.

Read the codes with a hybrid-compatible scanner and write down the freeze frame data
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Make sure the battery cooling air intake is clean
Check the 12 V auxiliary battery, which can also trigger warnings
Leave any high-voltage measurements to a specialized repair shop

Good to know

It can trigger limp mode.
It affects emissions.

What each character of P0B43 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
B: Subsystem depends on the code range
43: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0B43?

If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.

What causes code P0B43?

The most common causes are: open sense line letting the input float high; battery controller software misreading the channel; measurement input of the cell monitoring chip failed.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.