Powertrain, generic · Hybrid propulsion

P0BAF Hybrid/EV Battery Voltage Sense X Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0BAF covers a sense X signal that is electrically present yet does not behave like a real cell. For model year 2016 GM documents two versions in the same booklet. The Volt controller fails it when X moves in a different direction from the pack average, or by less than 0.005 V while that average moves more than 0.022 V, for 7 s within 8 s, Type A. The ELR variant samples every 200 ms, needs average movement above 0.006 V and fails after 20 of 40 samples, one trip. The eAssist hybrid asks for at least half of the average change, Type B over two trips, and GM's 2019 processor uses a 0.005 V trend test. Since the check pauses during circuit, low or high faults, P0BAF points to a stuck measurement rather than a broken wire.

Likely causes

Sense X value stuck while the pack voltage changes
Calibration of the battery controller requiring reprogramming
Cell X with deviating internal resistance

Symptoms

  • MIL without obvious driving change
  • Reduced electric range in some cases

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 xwiring harnessbms

Related codes

P0BAEP0BB0P0BB1P0BB2P0BAAP0BB4

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