P0B8B marks an open circuit on voltage sense Q, the seventeenth channel. In GM's BAS Plus mild hybrid tables Q is the first channel whose open test is blocked by code P1B37 instead of P1B36, which suggests it sits in the next measuring group of the battery interface module; the criterion stays lines N and N-1 below 1.4 V with a change above 0.5 V in 200 ms, 7 of 10 samples, Type B. GM's 2019 battery controller uses 0.8 s in a 1.6 s window, the 2016 version 0.6 s, both Type A with the 1.3 V and 36 mV criteria. The 2011 Volt list includes P0B8B as well. The two-mode NiMH trucks have no circuit code for block 17. Ford does not list it. Typically the vehicle restricts or blocks electric operation until repaired.
High severity. Can I keep driving?If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
Symptoms
- MIL and service vehicle message
- Electric operation blocked or limited
- Fuel consumption rises on hybrids
Most likely causes
- Sense lead Q open between cell tap and module
- Loose or corroded connector at the second measuring group
- Fault in the battery interface module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It can trigger limp mode.
- It affects emissions.
What each character of P0B8B means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- B: Subsystem depends on the code range
- 8B: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0B8B?
If the car still runs, drive as little as possible and go to a specialized repair shop. Do not touch the orange cables: they carry high voltage.
What causes code P0B8B?
The most common causes are: sense lead Q open between cell tap and module; loose or corroded connector at the second measuring group; fault in the battery interface module.
Related codes
- P0B8CHybrid/EV Battery Voltage Sense Q Circuit Range/Performance
- P0B8DHybrid/EV Battery Voltage Sense Q Circuit Low
- P0B8EHybrid/EV Battery Voltage Sense Q Circuit High
- P0B8FHybrid/EV Battery Voltage Sense Q Circuit Intermittent/Erratic
- P0B86Hybrid/EV Battery Voltage Sense P Circuit
- P0B90Hybrid/EV Battery Voltage Sense R Circuit
Sources
- gsi.ext.gm.com: 13OBDG05C Hybrid Diagnostics
- gsi.ext.gm.com: 19OBDG01 Hybrid Diagnostics
- gsi.ext.gm.com: 16OBDG01 Hybrid Diagnostics
- gsi.ext.gm.com: 11OBDG01 HYBRID Diagnostics
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.