P0A8F means the 14 V power module (DC/DC converter for the 12 V network) does not perform as expected even though its signals are electrically in range. GM's 2013 eAssist tables use it as a correlation test: with the APM commanded on and ignition voltage 9 to 32 V, the APM's own low-voltage reading and the run/crank voltage measured by the controller must agree within 4.5 V. A larger difference over 3.75 s in a 5 s window sets the code as Type B, two trips to MIL. A high resistance in the 12 V output path or ground, a drifting sensor or a converter that cannot hold its target can all cause this. P0A8D and P0A8E cover sensor circuit low/high faults.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- MIL and charging/hybrid warning
- Low or fluctuating 12 V voltage
Most likely causes
- High resistance in 12 V output cable, fuse link or ground
- Drifting voltage sensor in the module
- Converter unable to hold its target voltage
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- It affects emissions.
What each character of P0A8F means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- A: Hybrid or air and fuel
- 8F: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0A8F?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P0A8F?
The most common causes are: high resistance in 12 V output cable, fuse link or ground; drifting voltage sensor in the module; converter unable to hold its target voltage.
Related codes
- P0A8B14 Volt Power Module System Voltage
- P0A8C14 Volt Power Module System Voltage Unstable
- P0A8D14 Volt Power Module System Voltage Low
- P0A8E14 Volt Power Module System Voltage High
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.