Powertrain, generic · Hybrid propulsion

P0BB4 Hybrid/EV Battery Voltage Sense Y Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0BB4 is a plausibility code: the controller compares how the Y reading changes over time with the behaviour of all other cells. In the 16OBDG02 programme a sample counts as failed when the pack average moves by more than 0.022 V but Y has not trended at least 0.002 V the same way; 35 such results in 40 evaluations set a one-trip Type A fault. The 2019 hybrid powertrain control processor 2 uses the same frame with a 0.005 V trend. For the 2016 Volt the window is 7 s in 8 s. A frozen analogue input or a software problem in the battery controller are the typical findings, while a real cell defect is rarer. Unlike P0BB3, the signal is present, so the car usually keeps driving.

Likely causes

Analogue input Y frozen at one value
Battery controller software fault
Weak cell Y with sluggish voltage response

Symptoms

  • MIL, vehicle still drivable
  • Battery power occasionally limited

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–5,000
Time0.5–6 h

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

Parts involved

hv battery voltage sense ywiring harnessbms

Related codes

P0BB3P0BB5P0BB6P0BB7P0BAFP0BB9

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