Powertrain, generic · Hybrid propulsion

P0B8F Hybrid/EV Battery Voltage Sense Q Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B8F closes the channel Q group and stands for a sense Q signal that is erratic rather than absent or out of range. No manufacturer documents this code publicly. GM's tables for sense Q, from the 2011 Volt to the 2019 battery controllers, list circuit, range, low and high monitors only, and the Ford Fusion bulletin ends four channels earlier at N. CARB 1968.2 forms the basis: it calls for monitoring of the battery voltage sensors in a hybrid energy storage system and for codes that lead a technician to the faulty part. Physically, an erratic Q reading would point to an unstable connection between tap and measuring chip, such as a cracked crimp, a damaged flexible circuit or a cold solder joint. The next channel, R, starts at P0B90.

Likely causes

Cracked crimp at the channel Q tap
Damaged flexible circuit between cells and monitoring board
Cold solder joint at the measuring chip

Symptoms

  • Sporadic hybrid or EV warning
  • Power briefly reduced, normal after restart

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–5,000
Time1–8 h

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

Parts involved

hv battery voltage sense qwiring harnessbms

Related codes

P0B8BP0B8CP0B8DP0B8EP0B8AP0B94

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