Powertrain, generic · Hybrid propulsion

P0BB1 Hybrid/EV Battery Voltage Sense X Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0BB1 means the battery controller sees too much voltage on sense X. In GM's 2019 battery energy control module the threshold is 4.8 V or more, held for 1.4 s within a 2 s window, and the code is Type A, so the MIL comes on in the first trip. The 16OBDG02 programme allows up to 4.90 V and needs 14 failing samples out of 18, while the eAssist battery treats anything above 4.65 V in seven of ten samples as a Type B fault. These tests are suppressed while an open sense line or a lost communication with the cell monitoring slave is active. A real cell at that voltage would be dangerously overcharged, so a wiring fault towards the neighbour cell or a defective input is the more frequent finding.

Likely causes

Sense lead X shorted to the next higher cell
Measuring input X drifting high
Cell X genuinely over voltage

Symptoms

  • MIL in the first trip
  • Charging and regenerative braking disabled

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 xwiring harnessbms

Related codes

P0BAEP0BAFP0BB0P0BB2P0BACP0BB6

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