A new problem… ABS, VSC TRAC, VSC OFF, Brake, and Active TRAC lights all on…

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This has not been a good couple of days for the Cruiser. After changing my tstat over the weekend and chasing down my low voltage problem, now I’ve got all five of these ABS/traction lights on. They popped on this afternoon while driving. No alarm, and no CEL.

Brake performance is fine, and the ATRAC system is not activating. In fact, car drives perfectly normal. The brake pump/accumulator repressurizes in 37 seconds from a full bleed-down, so no issue there. What is puzzling abs frustrating is that I can’t seem to get it to display an ABS code. I jumpered the engine bay diagnostic port, but neither the ABS light nor the VSC lights blink. Of course, there are no OBD codes present.

Does this indicate a bad ABS computer, as others have experienced? Any reason why I can’t get the codes via the jumper method, or alternative methods to try. As always, thank you sincerely in advance.
 

Hugh Heifer

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Techstream did not identify mine. Turned out the ABS computer went bad. Took a while to figure it out. Brakes acted normal.
It could even be a gas cap.
I think if you search Christmas tree you may find some other randomness.

Also disconnect your battery for a bit then reconnect to see if it persists.

Without a code i am thinking no 02 issues
 
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BullElk

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I had the same thing occurring on the last LX I bought. The previous owner got a quote from the dealership of $3500 to replace a module. Maybe the VSC module. Located above accelerator. I used that to negotiate a smokin cheap price. I disconnected the module, cleaned circuit board and plugged it back in. I’ve never seen the lights since.
 
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Techstream did not identify mine. Turned out the ABS computer went bad. Took a while to figure it out. Brakes acted normal.
It could even be a gas cap.
I think if you search Christmas tree you may find some other randomness.

Also disconnect your battery for a bit then reconnect to see if it persists.

Without a code i am thinking no 02 issues
Yes, I've had similar issues on our Sequoia with an emissions-related CEL deactivating the VSC system. One time on our previous '06, it was the secondary air injection system, and on our current '03 Sequoia, a bad gas cap. Both times, the trucks went into limp mode. Of course, there was a CEL and OBD code in both cases. On the Cruiser right now, no CEL, no OBD code, and no limp mode. Thus, I am also thinking that there is no O2/emissions issue.

I had the same thing occurring on the last LX I bought. The previous owner got a quote from the dealership of $3500 to replace a module. Maybe the VSC module. Located above accelerator. I used that to negotiate a smokin cheap price. I disconnected the module, cleaned circuit board and plugged it back in. I’ve never seen the lights since.
I've been through this thread in detail:
Fix for ABS, VSC TRAC, VSC OFF, & Brake lights remain on no CEL, or how to repair an ECU - https://forum.ih8mud.com/threads/fix-for-abs-vsc-trac-vsc-off-brake-lights-remain-on-no-cel-or-how-to-repair-an-ecu.1122305/

This is exactly describing my issue. Considering that my ABS, VSC, and ATRAC systems are all non-functional, but the car is otherwise running/driving normally--ATRAC is not activating, brakes are working within spec, etc.--logic would suggest that the entire ABS/VSC/ATRAC module is faulty/not communicating, as @FJRyder describes. Also, the fact that the diagnostic port jumper to read the codes is not returning any codes--no blinks at all--seems to support that hypothesis.

While I am waiting for my Techstream cable, I am going to pull the module and pop it open and test the ceramic resonator, which seems to be the common failure point. I'll clean it, too, and maybe it will give me at least some temporary function.

@BullElk, out of curiosity, how did you clean your circuit board? Thanks!
 

Hugh Heifer

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If you determine you want to switch out a module try to find a used one. Pennies on the dollar compared to a new one and they so infrequently fail you will probably be okay with a used one for the life of your truck. I bought a new ABS computer and it was crazy expensive. I could have had one here in the classified for $150 but was so surprised by the diagnosis I did not even think to look in classified.
 

BullElk

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Excellent! Was it very dirty?
I could not tell it was dirty. I also cleaned the pin connector plug. That probably had more to do with it connecting and working properly than anything else.

I am trying to remember something else about that circuit board and with whom I talked to about it but…. There is a particular piece on the board that goes out causing the lights to come on and that piece can be replaced. There is a thread somewhere about a fellow mudder, I think in California, that can replace that particular piece for a reasonable price. Maybe someone else knows who that is.

Hopefully your issue is just a dirty or loose connector.
 
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I could not tell it was dirty. I also cleaned the pin connector plug. That probably had more to do with it connecting and working properly than anything else.

I am trying to remember something else about that circuit board and with whom I talked to about it but…. There is a particular piece on the board that goes out causing the lights to come on and that piece can be replaced. There is a thread somewhere about a fellow mudder, I think in California, that can replace that particular piece for a reasonable price. Maybe someone else knows who that is.

Hopefully your issue is just a dirty or loose connector.
Yes... that is the thread I linked to in post #6. There are three microcontrollers in the module, one each for ATRAC, VSC, and ABS. They each need an independent clock signal to function. Two of them use a quartz oscillator (like a quartz watch), and the third uses a ceramic resonator. Apparently, it's the ceramic resonator that commonly fails.

(Note: I am just parroting this verbatim from @FJRyder's excellent thread. I deserve no credit!)

I am psyching myself up to possibly replace that resonator chip... hopefully it doesn't come to that!
 
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Update… I got Techstream up and running on my laptop, and my cable should be arriving from Amazon tomorrow. In the meantime, I pulled the module from the under the dash to inspect, clean, and test.

Board and pin connectors look clean; no obvious signs of damage or corrosion.
6F8EE7A5-74B3-418A-9609-54BAB9060EEC.jpeg


The component that @FJRyder identified in his thread—the ceramic resonator—is the tiny chip in the lowermost left hand corner in my pic. Next to/below the word AISIN.

Using the resistance figures from @FJRyder, I measured the resonator with my DMM.

Left leg to center (gnd):
3BD7B600-714A-4A1B-9E30-5E9A0EF6529E.jpeg


Right leg to center:
86E652BD-F1A8-4C50-8F3C-3F77E5E7B9E9.jpeg


Left leg to right leg:
11564658-6AC2-4DFA-B3D3-A57F582CA647.jpeg


Except for the last figure—which is still out of spec—these are very similar to @FJRyder’s readings. I don’t want to jump to conclusions, but I am anticipating that Techstream will confirm no communication with the ABS/VSC mode. I’ll update as soon as my cable arrives and I can test with Techstream. I’ll update when I can test…
 
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Except for the last figure—which is still out of spec—these are very similar to @FJRyder’s readings. I don’t want to jump to conclusions, but I am anticipating that Techstream will confirm no communication with the ABS/VSC mode. I’ll update as soon as my cable arrives and I can test with Techstream. I’ll update when I can test…
This is definitely a bad resonator. It needs to be replaced. Left leg to right leg should be in the mega ohms.
 

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