P0BB1Hybrid/EV Battery Voltage Sense X 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
- P0BB1 means the battery controller sees too much voltage on sense X. In GM's 2019 battery energy control module the threshold is 4.8 V or more, held for 1.4 s within a 2 s window, and the code is Type A, so the MIL comes on in the first trip. The 16OBDG02 programme allows up to 4.90 V and needs 14 failing samples out of 18, while the eAssist battery treats anything above 4.65 V in seven of ten samples as a Type B fault. These tests are suppressed while an open sense line or a lost communication with the cell monitoring slave is active. A real cell at that voltage would be dangerously overcharged, so a wiring fault towards the neighbour cell or a defective input is the more frequent finding.
- What you may notice
- MIL in the first trip
- Charging and regenerative braking disabled
- Likely causes
- LikelySense lead X shorted to the next higher cell
- PossibleMeasuring input X drifting high
- RareCell X genuinely over voltage
- 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: €100 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.