Multiple ABS Codes

Hello all. Looking for some advice on some ABS codes. I recently had the heater core replaced in my son's 2008 Urbanrunner, and after the replacement we got the ABS dash light and the following codes:

C1223 - Malfunction in ABS system
U0073 - Control Module Communication Sys Off
U0123 - Lost Communication with Yaw Rate Sensor Module
U0124 - Lost Communication with Lateral Acceleration Sensor Module
U0125 - Lost Communication with Steering Angle Sensor Module

I'm no expert, but it seems odd that all of these sensors could go bad all at once, especially after having the dash ripped open. It seems to me like he may have left something disconnect while reassembling the dash. Any thoughts on what this could be?

The AC shop is declining to take a look at it so I'm on my own to figure this out.

 

First thing I would do is look for any unattached plugs or harnesses. They may have failed to reconnect something.

EDIT: FWIW, this is what AI says:
Those codes suggest the ABS system is having trouble communicating with multiple sensors over the CAN bus (Controller Area Network), which is the wiring network that lets vehicle modules talk to each other.

Given that the codes all popped up after a heater core replacement, it’s highly likely that a wiring harness or ground connection was disturbed under the dash. Here’s what I’d check:

• Loose or disconnected ground wires (especially behind the dash or in the center console area)
• Unplugged or damaged connectors related to the yaw rate sensor or steering angle sensor
• Pinched or stretched CAN wiring during reassembly
• Relevant fuses like ABS, ECU-IG, and GAUGE

Since U0073 (Bus Off) means the entire CAN communication line is down, the issue is almost certainly physical — not a failed sensor. I’d start by rechecking everything that was moved during the heater core job, especially around the HVAC box and center console.

 

A good shop or dealership can do a deep dive and diagnose a specific issue. Thing happened to my 2022 and it was one of the wheel speed sensors being faulty. Good luck.

 

First place to start, I second this 100%