P0B20Hybrid/EV Battery Pack Voltage Sense D Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P0B20 sets when pack voltage measurement D falls below its plausible minimum. The cause is usually electrical: a sense lead shorted to ground, an interrupted fuse or resistor in the measurement path, or a damaged controller input. No manufacturer documents P0B20 publicly. GM shows the analogous check on channel A, where its BECM sets P0ABC once pack-side voltage stays under 24 V for 1.6 s within 2 s, Type A, one trip. CARB requires out-of-range monitoring of battery voltage sensors in hybrid storage systems. The high counterpart is P0B21, plausibility faults are P0B1F. An implausibly low reading can block precharge, so the vehicle may not become ready.
- What you may notice
- Vehicle may not reach Ready or may shut down the high-voltage system
- MIL and hybrid/EV system warning on
- Battery power limited, reduced electric drive or assist
- Likely causes
- LikelySense lead of channel D shorted to ground
- PossibleFuse or resistor in the sense path open
- PossibleMeasurement input of the battery controller defective
- 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 – €2,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.