Powertrain, generic · Hybrid propulsion

P0B75 Hybrid/EV Battery Voltage Sense L Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

With P0B75 the battery controller rejects channel L because it reads above any value a real cell or block can reach. GM's lithium-ion systems in the 2016 Volt and the 2019 tables set it at 4.8 V or more over 1.4 s in a 2 s window, Type A, one trip; GM's BAS Plus mild hybrid at above 4.65 V in 7 of 10 samples, Type B. On the 2012 two-mode trucks, block 12 must exceed 23 V in 15 of 20 samples, sampled every 100 ms, before the code is stored as Type B. The pairing with P0B74 helps diagnosis: low points to a short downward, high to contact with a higher tap or a floating input. While it is active, charging and regeneration are normally limited to protect the pack.

Likely causes

Channel L lead touching a higher tap
Floating measuring input after an open reference line
Real overvoltage of the cell after a charging fault

Symptoms

  • Charging and regeneration limited
  • MIL and hybrid or EV warning

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–6,000
Time1–8 h

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

Parts involved

hv battery voltage sense lwiring harnessbms

Related codes

P0B72P0B73P0B74P0B76P0B70P0B7A

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.