t2d2

iTrader: (8)

I was looking at this post and noticed that little jumper on the lower right of the diagnostics box. When I had my intake manifold off a couple weeks ago, I was cleaning up various stuff that had fallen down there over the years and found a little pin jumper thingie under the diagnostics box that fit some of the terminals perfectly, so I set it aside in my testing kit in case it's useful in the future.

But seeing that photo, I immediately recognized the mystery jumper. Sure enough, it fits those two terminals. I had to look up what WA and WB signify, since I've never done anything on the car requiring attention to those. I found that they're for the ABS (anti-lock braking) system, but couldn't find much more than that. WA = ABS ECU, WB = ABS relay.

https://www.clublexus.com/forums/ls4...ml#post8223544
https://www.clublexus.com/forums/rx-...ml#post6556359

My guess is, the jumper is supposed to be in place otherwise ABS is deactivated? Wouldn't one expect to get a CEL in that case? Actually, scratch that, I see the ABS codes are separate from the engine codes. That second link above (RX300 thread) sounds like it's just a matter of jumpering the Tc and E1 pins (as opposed to E1 and TE1 for engine CELs) with the WA-WB jumper removed.

I'm curious if the jumper was removed because something in the ABS system isn't working or if someone dropped it down there and couldn't recover it...

t2d2

iTrader: (8)

The ABS and Cruise lights blink constantly with Tc/E1 jumpered and the WA-WB jumper removed. Constant blinking on engine CEL means no codes stored, so that's encouraging assuming I followed the right procedure.

Anyone know whether having that WA-WB jumper removed disables the ABS system? I've yet to do any uber emergency breaking that would tell me if it's been working or not.

t2d2

iTrader: (8)

Found this:

http://www.justanswer.com/lexus/3q85...97-causes.html

That would seem to confirm that the WA-WB jumper is normally in place and is only removed to retrieve ABS codes.