Powertrain, generic · Hybrid propulsion

P0B12 Hybrid/EV Battery Pack Current Sensor B Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

P0B12 covers a current sensor B signal that jumps or drops out in a way real current cannot, typically from a loose connector, a chafed signal wire or noise on the sensor ground. No manufacturer documents this exact code publicly. GM monitors its sensor B channel with the range limits P0B10 and P0B11 and compares it with sensor A through P0B13, which fails above a 10 A difference in 400 of 500 samples, Type A; an erratic channel often shows up there first. CARB requires circuit and rationality monitoring for hybrid battery inputs. Because the fault comes and goes, the code may be the only trace, but during dropouts the controller can still cut battery power or light a warning.

Likely causes

Loose connector or poor terminal contact at the current sensor
Chafed signal or ground wire
Electrical noise on the sensor ground

Symptoms

  • Intermittent hybrid or EV warning
  • Short power reductions during dropouts
  • Code stored without lasting symptoms

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–1,200
Time1–4 h

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

Parts involved

hv battery pack current sensor bwiring harnessbms

Related codes

P0B0EP0B0FP0B10P0B11P0B13P0AC3

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