P0B48: Hybrid/EV Battery Voltage Sense C Circuit High

No healthy lithium-ion cell reaches 4.8 V, which is why GM's battery energy control module treats a channel C reading of 4.8 V or more for 1.4 s within a 2 s window as a sensing fault and stores P0B48, Type A, one trip. On the 2012 two-mode full-size hybrids the threshold is scaled to a nickel-metal hydride block: block 3 above 23 V in 15 of 20 samples, Type B, two trips. Because the controller cannot trust the reading, it usually narrows the allowed charge and discharge power to protect the cells. For the driver this means less electric assist and possibly no plug-in charging. A cell that is really overcharged triggers separate cell voltage codes, not this one.

Symptoms

• MIL and hybrid or EV system warning
• Reduced charge and discharge power
• Plug-in charging refused

Most likely causes

• Channel C sense line touching a tap of higher potential
• Failed measuring input or reference in the monitoring electronics
• Monitoring software fault, check for controller updates

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. Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
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 P0B48 means

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

Frequently asked questions

Can I keep driving with code P0B48?

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 P0B48?

The most common causes are: channel C sense line touching a tap of higher potential; failed measuring input or reference in the monitoring electronics; monitoring software fault, check for controller updates.

Related codes

• P0B45Hybrid/EV Battery Voltage Sense C Circuit
• P0B46Hybrid/EV Battery Voltage Sense C Circuit Range/Performance
• P0B47Hybrid/EV Battery Voltage Sense C Circuit Low
• P0B49Hybrid/EV Battery Voltage Sense C Circuit Intermittent/Erratic
• P0B43Hybrid/EV Battery Voltage Sense B Circuit High
• P0B4DHybrid/EV Battery Voltage Sense D Circuit High
• P0ABDHybrid/EV Battery Pack Voltage Sense A Circuit High

Sources

• gsi.ext.gm.com: 19OBDG01 Hybrid Diagnostics
• gsi.ext.gm.com: 12OBDG06 Hybrid Diagnostics
• law.cornell.edu: 13 CCR 1968.2

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.