P0B64: Hybrid/EV Battery Voltage Sense I Circuit Range/Performance

P0B64 is a rationality fault: channel I is connected and reads a believable number, yet it does not move with the other cells. GM's 2016 Chevrolet Volt compares the movement of each cell with the average; if channel I does not follow when the average moves by more than 0.022 V, 7 out of 8 seconds fail the check, Type A. The 2019 hybrid powertrain control processor 2 tables keep the idea but count samples, 35 failures out of 40 at 100 ms. On the 2012 two-mode trucks the same code belongs to nickel-metal hydride block 9, whose scaled value must stay within 70 V of the pack voltage. Because the input is alive but stuck or drifting, a software update or the monitoring board is a likelier fix than wiring.

Symptoms

• MIL on, vehicle drives normally
• Reduced hybrid assist or electric range

Most likely causes

• Channel I measuring input frozen at a constant value
• Battery controller software misjudging the channel
• High-resistance cell tap damping the signal

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. Compare the reading with other engine data while varying the engine speed.
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 P0B64 means

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

Frequently asked questions

Can I keep driving with code P0B64?

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 P0B64?

The most common causes are: channel I measuring input frozen at a constant value; battery controller software misjudging the channel; high-resistance cell tap damping the signal.

Related codes

• P0B63Hybrid/EV Battery Voltage Sense I Circuit
• P0B65Hybrid/EV Battery Voltage Sense I Circuit Low
• P0B66Hybrid/EV Battery Voltage Sense I Circuit High
• P0B67Hybrid/EV Battery Voltage Sense I Circuit Intermittent/Erratic
• P0B5FHybrid/EV Battery Voltage Sense H Circuit Range/Performance
• P0B69Hybrid/EV Battery Voltage Sense J Circuit Range/Performance

Sources

• gsi.ext.gm.com: 16OBDG01 Hybrid Diagnostics
• 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.