P0BB1 code meaning
Hybrid/EV Battery Voltage Sense X Circuit High
Powertrain system Generic code P0Bxx codes Check engine light
What P0BB1 means
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.
P0BB1 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 8 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0BB1
- MIL in the first trip
- Charging and regenerative braking disabled
Common causes of P0BB1
- Most likelySense lead X shorted to the next higher cell
- PossibleMeasuring input X drifting high
- Less likelyCell X genuinely over voltage
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery voltage sense xWiring harnessBms
What each part of P0BB1 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| B | Area: hybrid propulsion. |
| B1 | The exact fault in that area. |
What to do next
- Note P0BB1 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0BB1
What does P0BB1 mean?
P0BB1 means "Hybrid/EV Battery Voltage Sense X Circuit High". P0BB1 means the battery controller sees too much voltage on sense X. It is a generic code, so it means the same on every make.
Is it safe to drive with P0BB1?
Drive gently and only to a workshop. With P0BB1 the car can go into limp mode (reduced power) to protect itself.
Will P0BB1 fail an emissions test?
Yes, it can. P0BB1 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0BB1 to fix?
Difficulty: workshop only. A typical repair takes 1 to 8 hours of work. This is a job for a workshop.
Will P0BB1 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.