P0BB0: Hybrid/EV Battery Voltage Sense X Circuit Low

When channel X reads too low, P0BB0 is stored. In GM's eAssist mild hybrid the battery interface module sets it below 1.4 V in seven of ten samples at 200 ms, provided the 12 V system is above 8.8 V and the group fault P1B38 is not active, as a two-trip Type B fault. The 2011 Volt and the 16OBDG02 programme work with a far lower limit of about 0.2 V, the latter in 14 of 18 samples at 100 ms, Type A. That difference reflects the cell chemistry and how much voltage a healthy cell can lose. Because an open lead is caught first by P0BAE, a stand-alone P0BB0 is more often a short in the sense harness, a failed input or a cell that has collapsed. Expect reduced power and blocked charging.

Symptoms

• Hybrid system warning and MIL
• Electric assist or propulsion reduced
• Charging not possible

Most likely causes

• Short between sense lead X and a lower potential
• Defective measuring channel X in the monitoring electronics
• Cell X collapsed or internally shorted

What to check, in order

Start with the simplest. You can tick off each step.

1. Read the codes with a hybrid-compatible scanner and write down the freeze frame data
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Make sure the battery cooling air intake is clean
4. Check the 12 V auxiliary battery, which can also trigger warnings
5. Leave any high-voltage measurements to a specialized repair shop

Good to know

• It can trigger limp mode.
• It affects emissions.

What each character of P0BB0 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• B: Subsystem depends on the code range
• B0: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0BB0?

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 P0BB0?

The most common causes are: short between sense lead X and a lower potential; defective measuring channel X in the monitoring electronics; cell X collapsed or internally shorted.

Related codes

• P0BAEHybrid/EV Battery Voltage Sense X Circuit
• P0BAFHybrid/EV Battery Voltage Sense X Circuit Range/Performance
• P0BB1Hybrid/EV Battery Voltage Sense X Circuit High
• P0BB2Hybrid/EV Battery Voltage Sense X Circuit Intermittent/Erratic
• P0BABHybrid/EV Battery Voltage Sense W Circuit Low
• P0BB5Hybrid/EV Battery Voltage Sense Y Circuit Low

Sources

• gsi.ext.gm.com: 13OBDG05C Hybrid Diagnostics
• gsi.ext.gm.com: 16OBDG02 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.