P0A09 on GMC: How to Diagnose & Fix
DC/DC Converter Status Circuit Low
1 GMC model · 1 documented issue
P0A09 on GMC by model: symptoms, diagnosis and fix
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.
Common Symptoms
- DC fast charging capping at 100-150 kW instead of 350 kW
- Charge port door not opening
- Charging session ending prematurely
- Unable to initiate charging at some stations
- Battery preconditioning not activating before arrival at charger
How to Fix
Pre-condition the battery for DC fast charging by enabling the "target charge station" feature in navigation — this warms the battery to optimal temperature before arrival. Ensure the latest OTA software update is installed, as GM has improved charging algorithms. For charge port door issues, the actuator can be replaced under warranty. Try multiple charger brands if one consistently fails to connect.
Sources for this issue (1)
P0A09 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0A09 mean on a 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 it is documented across 1 model: Hummer EV SUV.
What are the most common causes of P0A09?
The most common causes of P0A09 are: 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). The specific cause varies by vehicle.
How much does it cost to fix P0A09 on a GMC?
Repair costs vary widely with the root cause and GMC model; each issue on this page carries its own estimate where one is published.
Looking for P0A09 on a different make?
View P0A09 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.