Powertrain, generic · Hybrid propulsion

P0B72 Hybrid/EV Battery Voltage Sense L Circuit

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B72 reports an open circuit on voltage sense L, the twelfth channel. One detail sets it apart from its neighbours: GM's 2011 hybrid tables list every open sense line code from P0B3B upward except P0B72 (and P0B90), so the early system did not use it, while L's range, low and high codes were present. Later GM tables include it. The BAS Plus mild hybrid sets it when lines N and N-1 fall below 1.4 V with a change above 0.5 V in 200 ms, 7 of 10 samples, Type B; the 2019 battery energy control module uses its adjacent-cell, balancing and splice tests within 0.6 s, Type A. Ford's Fusion plug-in hybrid bulletin for 2019-2020 includes P0B72 and replaces the traction battery.

Likely causes

Open sense lead, crimp or cell tap on channel L
Internal traction battery failure, pack replacement (Ford Fusion PHEV)
High-resistance splice or bus bar joint

Symptoms

  • No start or no ready mode
  • Battery or hybrid system warning
  • Charging aborted

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€80–8,000
Time0.5–8 h

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

Parts involved

hv battery voltage sense lwiring harnessbms

Related codes

P0B73P0B74P0B75P0B76P0B6DP0B77

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov.