Yaris 2004: ABS issue

[YarisPie]

Hello. I've had an ABS issue on my French-built Yaris hatchback aut 1.3 2004 for a good while now.

Issue

- The ABS system kicks in during slow rolls with light pressure on the brake pedal.

To rule out the rear

-A few weeks ago I got both rear wheel bearings changed; it had no effect on the ABS issue. The bearings had to be changed anyway.

Visual inspection

- Last weekend I inspected both front sensor cables for cracks or outer wear. 
I noticed that the left one had the number 89543-0D010 in white and the right one had the number 89542-0D010 in yellow.

Question

- Since one is white and one is yellow, does it indicate which one is the sensor OEM? Or are the different colors irrelevant?

Also, the left one looked way newer compared to the right one.

So far

- Been to multiple garages that used different scan tools on the car without being able to tell which wheel is causing the issue.

Other

- Two garages also inspected the tone rings and told me they were completely fine.

I've had the issue with both of my OEM Yaris wheels with nearly new and balaced tires.

I've also changed front and rear brake pads about 6 months ago.

Trying to figure out which front side to focus on first. Thanks!