Powertrain, generic · Hybrid propulsion

P0B70 Hybrid/EV Battery Voltage Sense K Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B70 says that cell voltage K reads too high to be genuine. GM's 2019 battery energy control module sets it at 4.8 V or more, held for 1.4 s within 2 s, as a Type A fault with immediate MIL, and only when no communication loss, open sense line or internal module fault takes precedence. The same principle appears with other numbers elsewhere at GM: 4.65 V and 7 of 10 samples on the BAS Plus mild hybrid, 23 V for nickel-metal hydride block 11 on the 2012 two-mode trucks. The difference to P0B6F is the direction, not the location: a high reading typically comes from a lead touching a higher potential, a low one from a short to a lower one. Charging is usually blocked while it is active.

Likely causes

Channel K lead in contact with a higher tap
Floating measuring input after loss of its lower reference
Cell monitoring chip fault

Symptoms

  • Charging blocked
  • MIL and power limitation

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 kwiring harnessbms

Related codes

P0B6DP0B6EP0B6FP0B71P0B6BP0B75

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