Powertrain, generic · Hybrid propulsion

P0B43 Hybrid/EV Battery Voltage Sense B Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

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.

Likely causes

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

Symptoms

  • MIL and hybrid warning on
  • Charging or electric drive limited

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€50–5,000
Time0.2–6 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

hv battery voltage sense bwiring harnessbms

Related codes

P0B40P0B41P0B42P0B3EP0B17

References: gsi.ext.gm.com, law.cornell.edu.