2007 Avalon. Speedometer quit working, "ABS", "BRAKE", Check Engine" Lights

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Once the ABS module is communicating I think the tool will work fine on this car. The lack of communication is a good sign the ABS module is hosed. As Clinebarger said check power and ground to it first.
 

AlphaOmega

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@Trav, @clinebarger, @The Critic,

So I have received now a 2nd used ABS pump + computer combo for my 2007 Avalon with optional traction and stability control. For the life of me I can separate computer from the pump. I undo the bolts the supposedly hold computer to pump body and pry and pry and pry to no avail!

Both combo units have one corner of the computer as if welded to the pump body. I mangled computer's plastic body of the first unit by hammering screwdriver between it and the pump body all around the perimeter and still want able to separate the two!!

Now I have a 2nd used combo from eBay and still no success splitting computer from the pump! Is there a trick a separating the two? The YouTube video I've seen makes it seem very easy, like so (2:20):



PXL_20211204_201043655.jpg
 
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It's possible that the Motor power connection is soldered to the Board instead of it having 2 Spade connections. If that's the case, You'll need to replace the entire unit & bleed the brakes.

I haven't personally ran across this on a Toyota, But if the Module doesn't easily pry off the Motor Connection.....It about has to be soldered.
 
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DEFINITELY take the time to inspect all 4 harnesses to the wheel speed sensors. The fronts are probably the first to go since they deal with the additional twisting from steering. Really, you’d want to test for continuity as well, not just physically. You’d have to have a manual or physically trace them to find the other end to trace it through.

for it to work, and then not work, also suggests the fickle nature of a physical problem.

all of the lights lit up, and the Speedo, and the odo, rely on vehicle speed data.
 
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AlphaOmega

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DEFINITELY take the time to inspect all 4 harnesses to the wheel speed sensors. The fronts are probably the first to go since they deal with the additional twisting from steering. Really, you’d want to test for continuity as well, not just physically. You’d have to have a manual or physically trace them to find the other end to trace it through.

for it to work, and then not work, also suggests the fickle nature of a physical problem.

all of the lights lit up, and the Speedo, and the odo, rely on vehicle speed data.

It's NOT an intermittent issue. I've driven a 1000+ miles since it happened. Just the speedometer and odometer don't work. Everything else does. "ABS", "Brake", and "check engine" lights are always on. My scanner gets "communication error" when trying to read codes from ABS module.

Do you know if ABS computer is splittable from the ABS pump on an 07 Avalon with optional VSC? There are videos on YouTube were people easily separate them on cars with just ABS, but without VCS
 

AlphaOmega

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It's possible that the Motor power connection is soldered to the Board instead of it having 2 Spade connections. If that's the case, You'll need to replace the entire unit & bleed the brakes.

I haven't personally ran across this on a Toyota, But if the Module doesn't easily pry off the Motor Connection.....It about has to be soldered.

If you watch just for 10 seconds the video in post #43, from 2:22, you can see how easily he splits computer from the pump body. That car does not have VCS, I believe. Mine, with VCS had a just about identical looking pump+computer. It's attached with 4 screws to the body - just like on the car in the video in post #43.

On both used units that I've received from eBay, after I remove the 4 screws, I can lift the computer about 1 cm at 3 corners, but not 4th! Could it be soldered just on that one corner?? But not be soldered at all on cars with just ABS, but without VCS?

Thanks!
 
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It's NOT an intermittent issue. I've driven a 1000+ miles since it happened. Just the speedometer and odometer don't work. Everything else does. "ABS", "Brake", and "check engine" lights are always on. My scanner gets "communication error" when trying to read codes from ABS module.

Do you know if ABS computer is splittable from the ABS pump on an 07 Avalon with optional VSC? There are videos on YouTube were people easily separate them on cars with just ABS, but without VCS
My error - I thought it worked well then didn’t. Ok. The communication error between ABS and ECU is telling. Either the ECU isn’t seeing the ABS unit or the ABS unit isn’t seeing the ECU and responding how the ECU expects. This could be a problem with either of the units (Does the ABS unit have power? Is the fuse good?) I’m not sure if the communication for this is on one of the communication buses or if it’s a direct line - if I was in your shoes, I’d be looking for some kind of schematic to identify how they talk, and start with inspecting connectors, making sure all the pins are at the right height.

ABS Splittable? That I don’t know.

-m
 
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@Trav, @clinebarger, @The Critic,

So I have received now a 2nd used ABS pump + computer combo for my 2007 Avalon with optional traction and stability control. For the life of me I can separate computer from the pump. I undo the bolts the supposedly hold computer to pump body and pry and pry and pry to no avail!

Both combo units have one corner of the computer as if welded to the pump body. I mangled computer's plastic body of the first unit by hammering screwdriver between it and the pump body all around the perimeter and still want able to separate the two!!

Now I have a 2nd used combo from eBay and still no success splitting computer from the pump! Is there a trick a separating the two? The YouTube video I've seen makes it seem very easy, like so (2:20):



View attachment 80050

If you already buggered one why not finish it off by prying the cover off by any means to see what it is that is holding it?
 

AlphaOmega

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If you already buggered one why not finish it off by prying the cover off by any means to see what it is that is holding it?

Once again, I am amazed at the absence of forum support for technical troubleshooting and DIY for Toyota. Barren forums, full of dead-end threads on technical issues vs an older Merc or BMW, that have support galore. Luckily one useful individual showed up on a Lexus forum, who provided me with the following:

You can't just unbolt computer from ABS body on some Toyota models (presumably those with optional VCS) . In my case Toyota doesn't want you too.

1. 1st you have to cut the top off
#1.jpeg


2. Once that's done the board is exposed. One has to de-solder 64 joints to remove it
#2.jpg


3. After de-soldering joints, board comes out:
#3.jpeg


4. Here is the 1st guilty party that is preventing computer from separating from ABS body:

Inked#4_LI.jpg


5. And the wire (2nd guilty party) that connects the pump to computer must also be uncrimped:
Inked$5_LI.jpg


Jeez, almost a week searching internet, across 3 different forums, but glad I now know the answer: need to replace the whole assembly and bleed the brakes
 
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Yeah, not a lot for Toyota sites, just fanboi's talking about how good they are. TBH I've always thought these were disposable products, not really meant for long term usage.
 
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To be honest, I have never seen anyone have a reason to disassemble the two sections. Can I ask why?
 
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Once again, I am amazed at the absence of forum support for technical troubleshooting and DIY for Toyota. Barren forums, full of dead-end threads on technical issues vs an older Merc or BMW, that have support galore. Luckily one useful individual showed up on a Lexus forum, who provided me with the following:

You can't just unbolt computer from ABS body on some Toyota models (presumably those with optional VCS) . In my case Toyota doesn't want you too.

1. 1st you have to cut the top off
View attachment 80295

2. Once that's done the board is exposed. One has to de-solder 64 joints to remove it
View attachment 80296

3. After de-soldering joints, board comes out:
View attachment 80297

4. Here is the 1st guilty party that is preventing computer from separating from ABS body:

View attachment 80298

5. And the wire (2nd guilty party) that connects the pump to computer must also be uncrimped:
View attachment 80299

Jeez, almost a week searching internet, across 3 different forums, but glad I now know the answer: need to replace the whole assembly and bleed the brakes
They didn't make that easy did they.
 

AlphaOmega

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To be honest, I have never seen anyone have a reason to disassemble the two sections. Can I ask why?

I did not do it, a person on a Lexus forum did and provided pictures. I've just reposted them here and regurgitated his commentary. I assume he was just very curious why on his Lexus the ABS computer is not detachable from ABS body, when there are several+ videos on YouTube showing how easy it is to separate the computer. The are also several repair services that advertise online repairing your the ABS computer or selling you a repaired ABS computer. This repair, as far as I understand, is only applicable to ABS modules without vehicle stability assist and traction control. In those cars ABS computer detaches easily from the ABS assembly.

Here's an example of one such service offered:
Screenshot_20211207-123913.jpg


They specifically indicate to remove computer and only send it and not the whole assembly to them:
Screenshot_20211207-123922.jpg


They didn't make that easy did they.

There must be a good enough technical reason why Toyota does not want the computer to be separated from ABS assembly on vehicles with VSC and traction control. Don't know what it might be
 
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It's clear the VSC type and the non-VSC are completely different. The body is a different shape, the plug is different, the lines don't match.
 

AlphaOmega

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It's clear the VSC type and the non-VSC are completely different. The body is a different shape, the plug is different, the lines don't match.

I initially thought the difference was the same as between the Camry and the Avalon cars themselves - size and shape wise they are different, but otherwise totally identical.
 
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Once again, I am amazed at the absence of forum support for technical troubleshooting and DIY for Toyota.

ive run into similar with Lexus. Unless it’s tires, wheels, or stereo upgrades, the common mantra is often, “the guys that designed it know better than you do. Take it to a dealer.” Granted, of the toyota products I’ve known, by the time a part fails, it’s usually Totally Done and not worth the time to resurrect it.

add Volvo, Jeep and Chrysler vans to the list of excellent forum support. Having owned all three, they have solid communities. The Jeep guys go nuts, even the older ones, with board resolders and other in-the-weeds threads.
 
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ive run into similar with Lexus. Unless it’s tires, wheels, or stereo upgrades, the common mantra is often, “the guys that designed it know better than you do. Take it to a dealer.” Granted, of the toyota products I’ve known, by the time a part fails, it’s usually Totally Done and not worth the time to resurrect it.

add Volvo, Jeep and Chrysler vans to the list of excellent forum support. Having owned all three, they have solid communities. The Jeep guys go nuts, even the older ones, with board resolders and other in-the-weeds threads.
Toyota doesn’t make it easy for people to reverse engineer and hack - it’s like a Apple product except for planned obsolescence and hostility towards 3rd party repair. There was someone who tried to modify the audio system on a new Subaru - the installer said even a Tesla was easier. The Japanese tend to engineer to reduce long-term cost(not anymore), the Germans tend to engineer for engineering’s sake.

Add VW, Mercedes and even Range Rovers to the second list. Hell, there’s people hacking away at Teslas - if you know a little HTML/CSS, JavaScript(and node.js), C# and some electrical skills.
 
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“the Germans tend to engineer for engineering’s sake.”

LOL - indeed! Electric brake vacuum pump backing up a Venturi pump supplying vacuum to the brake booster in a naturally-aspirated vehicle? yes…., looking at you, Volvo….
 
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