P0AC1: Hybrid/EV Battery Pack Current Sensor A Circuit Low

P0AC1 is set when the output of the pack current sensor falls below the valid window, so that the converted current would be an impossible discharge or charge value. GM documents it in several hybrid tables. In the 2016 and 2019 versions the Hall-effect sensor fails when the result is below -365.1 A for 8 of 10 samples at 25 ms with system voltage above 10.2 V; the code is Type A with MIL on the first trip. An earlier GM pack in the 2013 table uses an output below 0.2 V, equal to about -230 A, with 7 of 10 samples and Type B. Typical causes are a lost supply or a signal shorted to ground. P0AC2 is the high side and P0AC0 the plausibility check.

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

Hybrid system or check engine warning on
Electric drive limited or vehicle will not go ready

Most likely causes

Sensor 5 V supply open or shorted
Signal wire shorted to ground
Hall current sensor failed internally

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
With the connector unplugged, check whether the signal wire is making contact with ground.
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 P0AC1 means

P: Powertrain: engine and transmission
0: Generic code: same on every make
A: Hybrid or air and fuel
C1: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0AC1?

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 P0AC1?

The most common causes are: sensor 5 V supply open or shorted; signal wire shorted to ground; hall current sensor failed internally.

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.