Powertrain, generic · Hybrid propulsion

P0B84 Hybrid/EV Battery Voltage Sense O Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B84 is stored when channel O sits above the upper limit of a credible cell voltage. For GM lithium-ion packs that limit is 4.8 V, held 1.4 s in a 2 s window, Type A; the 2016 program with a separate sense module tolerates up to 4.90 V and counts 14 failures in 18 samples, also Type A. GM's BAS Plus mild hybrid uses a lower ceiling of 4.65 V and a Type B rating. On the 2012 two-mode hybrids the reading belongs to NiMH block 15, which must exceed 23 V in 15 of 20 samples. For the driver the effect is a warning and a battery that is no longer charged fully or used for electric drive. Since true overvoltage is rare, the measuring lead and the input of the monitoring electronics are checked first.

Likely causes

Sense lead O shorted to a higher cell tap
Monitoring input of channel O reading too high
Cell overcharged because balancing failed

Symptoms

  • MIL and battery warning
  • Charging ends early
  • Less electric assist

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 owiring harnessbms

Related codes

P0B81P0B82P0B83P0B85P0B7FP0B89

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