What Does C1775 Mean?
The DC-DC converter, which steps down high-voltage battery power to 12V for the vehicle's accessory systems, has failed. This is a critical component in hybrid and electric vehicles. Without it, the 12V battery will drain and vehicle systems will lose power.
Safety Warning
Vehicle may lose all 12V power including lights, ABS, and power steering. Do not drive. The 12V battery will deplete quickly without the converter, potentially stranding the vehicle.
Common Causes
40%
Internal failure of the DC-DC converter power electronics
25%
Overload on the 12V system drawing excessive current through the converter
20%
Poor connection at the DC-DC converter input or output terminals
15%
HV battery voltage too low to allow proper DC-DC conversion
Diagnostic Steps
1
Step 1: Measure the 12V system voltage with the vehicle in READY mode — it should read 13.5-14.5V, indicating the DC-DC converter is charging. Below 12.5V suggests the converter is not functioning.
2
Step 2: Check the HV battery state of charge and voltage — verify it is within the normal operating range for the vehicle.
3
Step 3: Inspect the DC-DC converter connections — check both the HV input and 12V output terminals for tightness and corrosion.
4
Step 4: Monitor 12V system current draw to rule out a parasitic drain overloading the converter.
5
Step 5: If the converter is confirmed failed, replacement is required — this is a high-voltage component requiring HV-certified technician procedures.
Estimated Repair Cost
$800 - $3,000
Parts + labor, varies by vehicle and location
The DC-DC converter, which steps down high-voltage battery power to 12V for the vehicle's accessory systems, has failed. This is a critical component in hybrid and electric vehicles. Without it, the 12V battery will drain and vehicle systems will lose power.
The most common cause of C1775 (DC-DC Converter Failure) is: Internal failure of the DC-DC converter power electronics
Typical repair costs for C1775 range from $800 to $3,000, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle may lose all 12V power including lights, ABS, and power steering. Do not drive. The 12V battery will deplete quickly without the converter, potentially stranding the vehicle.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1775 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Chassis
System
Hybrid/Electric Power Conversion
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
