Powertrain, generic · Hybrid propulsion

P0B9C Hybrid/EV Battery Voltage Sense T Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B9C signals that sense T reads too low. On the 2012 two-mode trucks this is block 20, and because no block 21 exists the low test there looks at block 20 alone: below 2 V in 15 of 20 samples, Type B, while channels R and S each need their upper neighbour to read low as well. GM's lithium-ion controllers from the 2016 Volt to 2019 work with 0.2 V or less for 1.4 s within 2 s, Type A, the 16OBDG02 programme with under 0.20 V in 14 of 18 samples, and the eAssist mild hybrid with 1.4 V in 7 of 10 samples, Type B. Open sense line faults are evaluated first. For the driver the result is a warning and reduced power until the cause is repaired.

Likely causes

Sense lead T shorted to ground or a lower potential
Weak or discharged NiMH block 20 on two-mode packs
Failed measuring input for channel T

Symptoms

  • MIL and hybrid warning
  • Reduced power, engine may not shut off on hybrids

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 twiring harnessbms

Related codes

P0B9AP0B9BP0B9DP0B9EP0B97P0BA1

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