P0BAF: Hybrid/EV Battery Voltage Sense X Circuit Range/Performance

P0BAF covers a sense X signal that is electrically present yet does not behave like a real cell. For model year 2016 GM documents two versions in the same booklet. The Volt controller fails it when X moves in a different direction from the pack average, or by less than 0.005 V while that average moves more than 0.022 V, for 7 s within 8 s, Type A. The ELR variant samples every 200 ms, needs average movement above 0.006 V and fails after 20 of 40 samples, one trip. The eAssist hybrid asks for at least half of the average change, Type B over two trips, and GM's 2019 processor uses a 0.005 V trend test. Since the check pauses during circuit, low or high faults, P0BAF points to a stuck measurement rather than a broken wire.

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 without obvious driving change
Reduced electric range in some cases

Most likely causes

Sense X value stuck while the pack voltage changes
Calibration of the battery controller requiring reprogramming
Cell X with deviating internal resistance

What to check, in order

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

Read the codes with a hybrid-compatible scanner and write down the freeze frame data
Compare the reading with other engine data while varying the engine speed.
Make sure the battery cooling air intake is clean
Check the 12 V auxiliary battery, which can also trigger warnings
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 P0BAF means

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

Frequently asked questions

Can I keep driving with code P0BAF?

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 P0BAF?

The most common causes are: sense X value stuck while the pack voltage changes; calibration of the battery controller requiring reprogramming; cell X with deviating internal resistance.

Related codes

Sources

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.