TROUBLE IN ABS SYSTEM?

Perform the following steps to improve the connection of the EBCM Ground:

Remove the EBCM Ground. The EBCM Ground is located on the frame beneath the driver's side door. If multiple grounds are found in this location, the EBCM ground can be identified as the heavy (12-gauge) wire.
Clean the area, front and back, using a Whiz WheelÂ.
Install the ground, then the washer and then the bolt to the frame.
Important: It is important to use the bolts, washers and nuts specified in this bulletin. These parts have been identified due to their conductive finish.

Install a washer and nut to the back side of the frame.
Tighten
Tighten the nut to 9 NÂ m (79 lb in).

Cover the front and back side of the repair area using Rubberized Undercoating.
An additional check can be made to ensure a good connection for the Battery Cable to Frame ground. It is possible for this ground to cause similar symptoms with the ABS as described above.

Try this first and let me know if it worked.

The code C0265 on a 2001 Chevrolet Tahoe indicates an issue with the Electronic Brake Control Module (EBCM) circuit. So, I have seen the ABS control module go out and cause this code. here is a video on how to change it out:

https://youtu.be/lUotkKXG9dY?si=jEtEfDdomXIAFN6G

Let us know if you need anything else.