P0B4DHybrid/EV Battery Voltage Sense D Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- 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.
- What you may notice
- MIL and battery system warning
- Reduced acceleration and regenerative braking
- Charging power limited or charging refused
- Likely causes
- LikelyChannel D sense lead contacting a tap of higher potential
- PossibleDamaged measuring input in the monitoring electronics
- RareMoisture or contamination on the monitoring board creating leakage paths
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €50 – €5,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.