Powertrain, generic · Hybrid propulsion

P0B9E Hybrid/EV Battery Voltage Sense T Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B9E would describe a sense T signal that flickers. It lacks any public manufacturer documentation. Even the 2012 two-mode trucks, whose last NiMH block is channel T, monitor it only for range, low and high, and GM's lithium-ion controllers add a circuit test but no intermittent one. The requirement behind the whole code family comes from CARB 1968.2: battery voltage sensors of a hybrid energy storage system are monitored components, and manufacturers must store separate codes that lead to the smallest part replaceable in service. A technician facing this code would wiggle-test the channel T wiring while watching the cell voltage live and look for a reading that dips or spikes for a fraction of a second.

Likely causes

Loose or spread terminal in the channel T connector
Connection that opens with temperature changes
Electrical interference coupling into sense lead T

Symptoms

  • Intermittent warning lamp
  • Occasional brief loss of electric drive

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 twiring harnessbms

Related codes

P0B9AP0B9BP0B9CP0B9DP0B99P0BA3

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