P0A8C indicates that the output voltage of the 14 V power module, the DC/DC converter supplying the 12 V network of a hybrid or EV, fluctuates beyond what the control strategy accepts instead of settling at its target. Possible reasons include a poor 12 V connection, an aged 12 V battery that no longer buffers the network, or a regulation problem inside the converter. No manufacturer documents this code publicly; GM's APM tables only cover low, high and performance faults of the same voltage (P0A8D, P0A8E, P0A8F). For the driver, flickering lights, resets of electronic units or start/stop being disabled are typical. Unlike P0A8D/P0A8E the average voltage may still be normal.
Medium severity. Can I keep driving?If the battery warning light comes on, you could get stranded. Turn off electrical accessories and go straight to a repair shop.
Symptoms
- Flickering lights or display resets
- Charging or hybrid system warning
- Start/stop disabled
Most likely causes
- Loose or corroded 12 V battery terminal or ground strap
- Aged 12 V battery no longer buffering the network
- Unstable regulation inside the DC/DC converter
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P0A8C means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- A: Hybrid or air and fuel
- 8C: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0A8C?
If the battery warning light comes on, you could get stranded. Turn off electrical accessories and go straight to a repair shop.
What causes code P0A8C?
The most common causes are: loose or corroded 12 V battery terminal or ground strap; aged 12 V battery no longer buffering the network; unstable regulation inside the DC/DC converter.
Related codes
- P0A8B14 Volt Power Module System Voltage
- P0A8D14 Volt Power Module System Voltage Low
- P0A8E14 Volt Power Module System Voltage High
- P0A8F14 Volt Power Module System Performance
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.