Powertrain, generic · Hybrid propulsion

P0B5B Hybrid/EV Battery Voltage Sense G Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

When P0B5B appears, the battery controller has seen cell sense channel G at a level no usable cell would show, and it shuts down or restricts electric operation to stay on the safe side. GM documents the trigger for its lithium-ion systems as cell voltage G at or below 0.2 V for 1.4 s in a 2 s window, Type A, with the test held off while communication, open line or balancing faults are active. On the 2012 two-mode hybrids channel G is block 7, and the code needs blocks 7 and 8 together under 2 V in 15 of 20 samples, Type B. Sense wiring, connector pins and the monitoring input deserve attention before the cells, which have their own cell voltage codes.

Likely causes

Channel G sense line shorted to a neighbouring line
Damaged or backed-out pin in the monitoring connector
Failed measuring input on the monitoring module

Symptoms

  • Hybrid system warning and MIL
  • Electric drive disabled or restricted

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€50–5,000
Time0.3–6 h

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

Parts involved

hv battery voltage sense gwiring harnessbms

Related codes

P0B59P0B5AP0B5CP0B5DP0B56P0B60

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