ABS Module not communicating [SOLVED]

[Christian]

Hello everyone,
I’m trying to diagnose why my abs module is not communicating with the ECU in my car, nor will it communicate with my diagnostic tool.
2006 Toyota Highlander Hybrid Limited

It started yesterday, in snowy weather, I went to the store then went back to my car and lights start flashing for ABS and Hybrid system. I started with checking fuses for ABS, all of them are in good shape (none blown), then I pulled the battery lead to reset the computer and to no avail it’s still not there. I didn’t want to call for a tow since it wasn’t far from home, of course the brake pedal wasn’t very responsive and steering was a little stiffer than usual. When I got back I ran diagnostic for codes and and the ABS was not communicating, Hybrid Control, EMPS and Cruise Control popped up for the ABS (CODES: U0121 & U0129 ).
U0121: Lost communication with anti-lock brake system (abs) control module :: Current
U0129: Lost communication with brake system control module :: Current

Audible symptoms being intermittent clicking from the module

I’m hoping it’s not a faulty module, but I want to check everything I possibly can. I need to find the correct wiring diagrams (I’ve attached what I could find online).
Can someone help with which wires I should check and any other ideas they may have?
I’ll appreciate any responses and I’ll reply quickly to all of you, Thank you

Topic

[Christian]

UPDATE:

I did some digging around and found the brake control power supply (located in the rear left corner of the trunk under the paneling), and found some moisture in the compartment it sits. I noticed the edge was bulging a bit so I disconnected it and found some exploded resistors. Seeing as though this is likely the problem and needs to be replaced either way, I’m going to replace it and bring an update on the situation when that time comes.

Pictures included for anyone’s curiosity

[Christian]

Received a used replacement Brake Control Power Supply Module today and popped it in. No luck though.. Same issues as before

The plug looks clean, fuses all look good, and codes are still current

Anyone out there?

[Christian]

After testing the CAN wires on that circuit (all reading 60ohms), checked all powers and grounds to the Skid control ECU. All of them were good, so I ordered a used replacement skid control ecu (found the same part number from a 2007 highlander hybrid). When replacing the ecu I unhooked the negative on the battery for it, swapped it out. Once I cleared the codes, there was no longer any ‘current’ codes, no lights, and the brakes and power steering work better than they have in a long time .
Lastly, I had to do the zero calibration on the new unit.

I did not have to go to a dealer or use special software to have any calibration done on the ecu (zero point calibration done with diagnostic tool), I’m not sure if that’s because I used an ecu from the same model (off by a year), or because it does not require it.

Happy I got my car back, if anyone has questions on the process, lemme know.

[Author]

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