Powertrain, generic · Hybrid propulsion

P0B4D Hybrid/EV Battery Voltage Sense D Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P0B4D sets when cell sense channel D reports more voltage than the cell or block behind it can deliver. GM's limits are 4.8 V or more for 1.4 s within 2 s on lithium-ion packs (battery energy control module, Type A, one trip) and above 23 V for block 4 of the 2012 two-mode hybrids (15 of 20 samples, Type B, two trips). A practical first check is live data: if channel D sits far above its neighbours while the pack voltage and the other channels look normal, the fault is in the sense path, not in the cells. Typical findings are a sense lead that contacts a higher tap or a damaged measuring input. The controller limits power until the code is repaired.

Likely causes

Channel D sense lead contacting a tap of higher potential
Damaged measuring input in the monitoring electronics
Moisture or contamination on the monitoring board creating leakage paths

Symptoms

  • MIL and battery system warning
  • Reduced acceleration and regenerative braking
  • Charging power limited or charging refused

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€50–5,000
Time0.3–6 h

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

Parts involved

hv battery voltage sense dwiring harnessbms

Related codes

P0B4AP0B4BP0B4CP0B4EP0B48P0B52

References: gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.