ABS and other bulbs are on

Have you removed the cowl tray that runs across the rear of the engine compartment? If not you need to do that. This requires removing the windshield wiper arms, removing the cover over the tray, removing the windshield wiper motor, then finally removing the tray. Disconnect the 12V battery first, by removing the negative cable where it bolts to the body.

Then you should be able to find the skid control ECU which is part of the brake actuator assembly. The brake actuator assembly has multiple steel brake lines connected to it.

 

The picture you posted was fuzzy and I could not see if any steel brake hydraulic lines are bolted to the part. If you do not see this, keep looking.

The sound is abnormal. I don't know whether it is caused by the braking system. Now that you have the cowl removed, maybe you can pin down its source by listening at the engine compartment, if you get someone to help you depress the brake pedal or do whatever is required to invoke the sound.

 

Yes, I believe you have located the brake booster with master cylinder, which includes the skid control ECU.

 

good luck!

 

1. Since you have a JDM model, maybe it uses a different skid control ECU and a different wiring harness. I assume your repair manual came from the TMS USA techinfo.toyota.com website?

2. Did you try to retrieve the DTC, then clear them to see what happens?

 

My 2010 manual has a drawing of the skid control ECU connector which matches the photo of your wiring harness connector.

The skid control ECU assembly is designated A58 and the part number is 90980-12828.

Referring to your photo, pin #1 is the large pin in the bottom far right. Pin #15 is the medium sized pin in the bottom far left. The little pins on the bottom row are numbered #3 (on the right side) through #14 (on the left)

Pin #16 is above pin #3 while pin #27 is above pin #14, regarding the little pins on the row above the bottom row.

Pin #28 is the medium sized pin above pin #15, far left.

Pin #29, upper far right large pin, is above pin #1.

The little pins on the top row are numbered #31 on the right and end with #42 on the left. That is where you will find pins #34 and #35. Measure the resistance across those pins of the wiring harness connector.

There is no need to turn the car on while the wiring harness connector is removed. The 12V battery should have been disconnected prior to removing that connector. Using Mini VCI, you will need to clear whatever codes were logged, after you reconnect the wiring harness connector to the skid control ECU.

 

The 62 ohm reading shows that the skid control ECU is able to connect to the other two ECUs which each have 120 ohm terminators across the comm line. Two 120 ohm resistors in parallel will measure ~60 ohms. Therefore, the failure of communication is probably due to the ECU.

However, you can try cleaning the ECU terminals. Buy a can of electrical contact cleaner and spray the wiring harness connector as well as the ECU terminals. Or if you don't have that easily available, use 91% isopropyl alcohol that you can buy from your local drugstore (at least this is the case in the US) and use that to clean the terminals, using a Q-tip. Do not allow any cotton residue to remain on the terminals.

Then reconnect and see what happens. Use Mini VCI to clear any stored DTC and then drive the car around.

 

I suggest you use Mini VCI to make sure no DTC are logged and clear anything in history.

Since the only code you previously identified is U0129, lack of communications is the only known issue and the comm is via the two pins.

Drive the car and see whether the same DTC reappears or if a new code is logged.