Powertrain, generic · Hybrid propulsion

P0B89 Hybrid/EV Battery Voltage Sense P Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B89 covers the opposite case to P0B88: the voltage reported on channel P is above the plausible range. GM's 2012 two-mode hybrids assign P to NiMH block 16 and set the code when the block exceeds 23 V in 15 of 20 samples at 100 ms, Type B, provided no battery controller fault P0A1F is active. In lithium-ion systems GM sets 4.8 V or more for 1.4 s in 2 s as the limit, Type A, while the BAS Plus mild hybrid reacts above 4.65 V. GM's 2016 program with a separate sense module allows up to 4.90 V. Overcharging is unlikely to be the cause because the controller stops charging well below these values; a sense lead reaching a higher tap or an input fault is the usual explanation. Expect restricted charging.

Likely causes

Lead P in contact with a higher cell tap
Input fault in the cell monitoring electronics
Genuine overvoltage of the cell or block

Symptoms

  • Charging restricted
  • MIL and hybrid 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 pwiring harnessbms

Related codes

P0B86P0B87P0B88P0B8AP0B84P0B8E

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