P0BB4Hybrid/EV Battery Voltage Sense Y Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0BB4 is a plausibility code: the controller compares how the Y reading changes over time with the behaviour of all other cells. In the 16OBDG02 programme a sample counts as failed when the pack average moves by more than 0.022 V but Y has not trended at least 0.002 V the same way; 35 such results in 40 evaluations set a one-trip Type A fault. The 2019 hybrid powertrain control processor 2 uses the same frame with a 0.005 V trend. For the 2016 Volt the window is 7 s in 8 s. A frozen analogue input or a software problem in the battery controller are the typical findings, while a real cell defect is rarer. Unlike P0BB3, the signal is present, so the car usually keeps driving.
- What you may notice
- MIL, vehicle still drivable
- Battery power occasionally limited
- Likely causes
- LikelyAnalogue input Y frozen at one value
- PossibleBattery controller software fault
- RareWeak cell Y with sluggish voltage response
- 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: €80 – €5,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.