Powertrain, generic · Hybrid propulsion

P0B5C Hybrid/EV Battery Voltage Sense G Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B5C marks an out-of-range high reading on cell sense channel G. For a technician the quickest plausibility check is arithmetic: the sum of all cell or block readings should match the pack voltage, so a single channel that reads far too high while the total stays normal is a sensing fault. GM formalises the limits as 4.8 V or more for 1.4 s within 2 s in the battery energy control module of its lithium-ion systems, Type A, one trip, and as more than 23 V for block 7 of the 2012 two-mode trucks and SUVs, 15 of 20 samples, Type B, two trips. Overcharged cells are flagged by other codes. Until the fault is fixed, battery power and charging are limited.

Likely causes

Channel G sense lead touching a higher cell tap
Faulty measuring input or reference in the module
Contamination or moisture on the monitoring board

Symptoms

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

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€50–5,000
Time0.3–6 h

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

Parts involved

hv battery voltage sense gwiring harnessbms

Related codes

P0B59P0B5AP0B5BP0B5DP0B57P0B61

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