P0A09: DC/DC Converter Status Circuit Low

The status signal that the DC/DC converter sends to the hybrid control module stays below its expected range, typically from a short to ground, an open line read as low, or a converter that pulls its status output down because of an internal fault. Mitsubishi uses P0A09 on the 2012-2013 i-MiEV for a DC-DC converter fault; its bulletins tie it to a failed on-board charger that blows the high-voltage fuse feeding the converter, after which the 12 V battery and drive battery stop charging. That usage predates the current split into P0A08, P0A09 and P0A10. Siblings: P0A08 covers the general circuit fault, P0A10 a signal stuck high. Expect warning lights and a 12 V battery that slowly runs flat.

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

Power unit, battery or hybrid warning light on
12 V battery not charged, voltage drops
On EVs the drive battery may also stop charging

Most likely causes

Blown high-voltage fuse feeding the converter, e.g. after an on-board charger failure (Mitsubishi i-MiEV)
DC/DC converter internal fault pulling the status output low
Status line shorted to ground or chafed harness
Faulty input stage in the hybrid/EV control module

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

Repair difficulty: hard
It can trigger limp mode.

What each character of P0A09 means

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

Frequently asked questions

Can I keep driving with code P0A09?

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 P0A09?

The most common causes are: blown high-voltage fuse feeding the converter, e.g. after an on-board charger failure (Mitsubishi i-MiEV); dC/DC converter internal fault pulling the status output low; status line shorted to ground or chafed harness.

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.