Powertrain, generic · Hybrid propulsion

P0BAA Hybrid/EV Battery Voltage Sense W Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Here the W reading is not missing but implausible: it fails to follow the rest of the pack. GM's 2019 hybrid powertrain control processor 2 watches for the average cell voltage to move more than 0.022 V between samples and then expects channel W to trend at least 0.005 V in the same direction; 35 failures in 40 samples at 100 ms give a Type A fault. The 16OBDG02 programme applies the same logic with 0.002 V. The eAssist system is more tolerant and only asks the cell to move half as far as the others once the average shifts more than 0.045 V, 20 of 40 samples, Type B. In the 2011 Volt tables W appears as sensor 23 of the rationality check. Drivers often notice nothing beyond the warning lamp.

Likely causes

Measuring input for W frozen at a fixed value
Battery controller software needing an update
Cell W reacting differently to load because of ageing

Symptoms

  • Warning lamp with little change in driving
  • Possibly limited regeneration or electric assist

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 wwiring harnessbms

Related codes

P0BA9P0BABP0BACP0BADP0BA5P0BAF

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