P0A8E: 14 Volt Power Module System Voltage High

P0A8E signals too high a voltage at the 14 V power module, the DC/DC converter supplying the 12 V side. In GM's 2013 eAssist tables it is the circuit-high check of the APM low-voltage sensor: a reading above 20 V for 1.5 s within a 2 s window, with ignition voltage 9 to 32 V, sets the code, and it passes below 19.5 V. GM rates it Type B, so the MIL comes on after two failing trips. Since the network should sit around 14 V, a reading over 20 V usually means a sense line shorted to a higher potential or a faulty sensor; a genuinely over-regulating converter would also threaten bulbs and modules. P0A8D is the low counterpart, P0A8F compares the sensor with the ignition voltage.

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

MIL and charging/hybrid warning
Very bright lights or failing bulbs if overvoltage is real
Converter may be shut down

Most likely causes

Voltage sense line shorted to a higher potential
Voltage sensor inside the power module failed
Converter regulating its output too high

What to check, in order

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

Measure the voltage with the engine off and running
Check the sensor's ground and make sure the signal wire is not receiving voltage from another circuit.
Clean and tighten the terminals
Check the accessory belt
Run a battery load test
Check the alternator wiring

Good to know

It affects emissions.

What each character of P0A8E means

P: Powertrain: engine and transmission
0: Generic code: same on every make
A: Hybrid or air and fuel
8E: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0A8E?

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 P0A8E?

The most common causes are: voltage sense line shorted to a higher potential; voltage sensor inside the power module failed; converter regulating its output too high.

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.