Powertrain, generic · Hybrid propulsion

P0B48 Hybrid/EV Battery Voltage Sense C Circuit High

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

No healthy lithium-ion cell reaches 4.8 V, which is why GM's battery energy control module treats a channel C reading of 4.8 V or more for 1.4 s within a 2 s window as a sensing fault and stores P0B48, Type A, one trip. On the 2012 two-mode full-size hybrids the threshold is scaled to a nickel-metal hydride block: block 3 above 23 V in 15 of 20 samples, Type B, two trips. Because the controller cannot trust the reading, it usually narrows the allowed charge and discharge power to protect the cells. For the driver this means less electric assist and possibly no plug-in charging. A cell that is really overcharged triggers separate cell voltage codes, not this one.

Likely causes

Channel C sense line touching a tap of higher potential
Failed measuring input or reference in the monitoring electronics
Monitoring software fault, check for controller updates

Symptoms

  • MIL and hybrid or EV system warning
  • Reduced charge and discharge power
  • Plug-in 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 cwiring harnessbms

Related codes

P0B45P0B46P0B47P0B49P0B43P0B4DP0ABD

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