P0A09 on GMC
DC/DC Converter Status Circuit Low
P0A09 on GMC vehicles indicates dc/dc converter status circuit low. Au7o has documented this code across 1 GMC model — most commonly on Hummer EV SUV. This code is found on hybrid and electric vehicles and indicates a low status signal from the DC/DC converter, the device that steps the high-voltage battery's power down to the 12-volt level needed to run lights, accessories, and charge the 12V battery. The converter reports its operating status to the vehicle's computer, and a low signal means it isn't operating or communicating as expected. Because the 12V system depends on this converter, problems can lead to a dead 12V battery, stalling, or no-start conditions. Causes typically include the converter itself, its wiring and connectors, or low system voltage.
Common Causes of P0A09
- •Faulty DC/DC converter (often integrated in the inverter assembly)
- •Open or shorted wiring in the DC/DC converter circuit
- •Poor electrical connection or corroded connector
- •Weak or failing 12V auxiliary battery
- •Converter over/under-voltage or overheating fault
- •CAN/communication fault to the converter
- •Faulty PCM/hybrid control module (rare)
P0A09 on GMC by Model
GMC Hummer EV SUV(1 issue)
- DC Fast Charging Speed Reduction and Charge Port Issues2024-2026
Some Hummer EV SUVs experience slower-than-expected DC fast charging speeds and intermittent charge port communication failures. The vehicle's 800V architecture should support 350 kW charging, but software limitations and battery temperature management can reduce speeds significantly. The charge port door actuator can also fail, preventing the port from opening. CCS connector fit issues at some public charging stations cause the vehicle to reject the charge session.
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View P0A09 across all makes →Frequently Asked Questions
What does P0A09 mean on GMC?▼
P0A09 stands for "DC/DC Converter Status Circuit Low." This code is found on hybrid and electric vehicles and indicates a low status signal from the DC/DC converter, the device that steps the high-voltage battery's power down to the 12-volt level needed to run lights, accessories, and charge the 12V battery. The converter reports its operating status to the vehicle's computer, and a low signal means it isn't operating or communicating as expected. Because the 12V system depends on this converter, problems can lead to a dead 12V battery, stalling, or no-start conditions. Causes typically include the converter itself, its wiring and connectors, or low system voltage. On GMC specifically, this code is documented across 1 model.
What causes P0A09 on GMC vehicles?▼
Common causes on GMC: Faulty DC/DC converter (often integrated in the inverter assembly), Open or shorted wiring in the DC/DC converter circuit, Poor electrical connection or corroded connector, Weak or failing 12V auxiliary battery, Converter over/under-voltage or overheating fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0A09 on a GMC?▼
Repair costs vary widely depending on the root cause and specific GMC model.
Which GMC models have P0A09 documented?▼
Au7o has documented P0A09 on 1 GMC model: Hummer EV SUV.