Are you absolutely sure the scanner(s) used by both shops were able to read both transmission and abs codes, including showing live data for both the transmission and abs?

 

Yes I am. I observed the scan process. They were able to select the car, model, engine and whether it was a Bosch or Denso ABS. Mine is Bosch. Both guys were baffled that there were lights on and no abs codes.

 

Does disconnecting the battery make any difference?

 

No. Tried many times. Note that there is no ECS light, only ABS and Brake light.

 

I hate to keep kicking a dead scan tool here, but when you say full scan, how full is a full scan to you? And when you say ECS, do you mean ECM as in engine control module? Or does ECS refer to electronic stability control? ECS is a new one to me. Did I miss altogether?

The reason I ask, is because when I read full scan, I'm expecting that to mean absolutely every module was checked for codes. I'd not only look at modules turning lights on, but also the ECM, the BCM, and even the instrument panel cluster. I'd be looking for lost communication codes in any and all modules as a start. That or circuit open/shorted codes.

With or without a scan tool, I'd want to look at wiring harnesses anywhere I can find them in the engine bay. See what you can under the dash, and look for any evidence of wiring damage. Rub throughs near sharp edges & corners, green crusty oxidations, burnt wiring, rodent dining, etc... If the car has a known accident history, pay attention to places where the body shop may have been working near harnesses.

One last sneaky thing I can think to try is pulling fuses, one at a time, for the ABS module and the instrument cluster. Pull a fuse and go for a test drive, see if/what changes. If no change, plug that fuse back in and pull the other; wash, rinse, repeat. It might not work for the cluster though. Depending on the factory installed bells & whistles, anti theft might need the cluster alive to even start the car. Keep in mind, this is only something to do after you absolutely know there are no codes to chase. Once you start pulling fuses, you introduce codes, and they don't need to be mistaken for actual problems. If, by chance, pulling the ABS or cluster fuse does restore normal shifting, you can start looking at that module and it's wiring as a root problem.

 

Thanks for your interest. And oops, somehow my 81 year old brain has created a new warning light. What I mean is NO CEL. I will see if I can edit my original post.

Both these shops used large tablet style scanners. I don't remember the manufacturers of the tablets. But both had built in information about the car. Both shops are pretty big and long established in town. It took them several minutes to run the tests so I am pretty sure these were full scans. And both of the men who did it run the shops and appear very experienced.

My first impulse was to check for wire damage, inspect sensors etc. Car has always been garaged and lives in California. No corrosion at all

One piece of new information. I disconnected ABS module and started car. Still have ABS and Brake light, no CEL, however speedometer no reads ZERO instead of 10 MPH.

I will work though your suggestions today. Thanks again

 

Find a shop with a big tablet style Snap-on scanner, supposedly the company that writes Snap-on software is the same company that writes the TIS software for Toyota. Codes are great but did anyone drive it while logging some data like vehicle speed and transmission parameters then review the logs for issues? It could be as simple as a bad vehicle speed sensor.

 

Just had a chance to drive. Yes, unplugged ABS connector, and, now shifts and drives normally. Speedometer reading zero. My thinking is that somehow the ABS was feeding bad info to the speedometer and transmission which was causing driveability problems.

 

Further info. I have driven quite a bit this afternoon with the ABS cable disconnected and the driveability is normal. Brakes normal. ABS, Brake lights on and speedometer still "0".

I have located a used ABS control module on EBay that is the exact part number of the Bosch unit on my car. I am thinking of buying it and transferring the control module to the pump assembly on my car. (1) Is that a sensible idea? (2) If I do that will the control box have to be re-programmed? It's only $90 so it seems like a good gamble to me since we really don't know what the problem is. Thoughts anybody?

 

I can't tell you if it would need a reflash, but I'm 90% on board with trying another ABS module regardless. I'm still a stickler for a certain amount of circuit testing before spending any money on anything on eBay. California car or not, powers, grounds, and communication circuits should always be tested before firing the parts cannon. Voltage drop testing is what I always recommend. I have little use for Ohm meters as they never test a circuit under live, loaded conditions. I would even settle for simple testing with a test light. That's for basic powers and grounds, though. Communication circuits need a scope to see a waveform. Do a visual inspection on the pins & terminals of the connector at the ABS module, too. Look for all the other stuff I recommended in my previous post no matter how California your car is.

One last thing you might be able to try on your own is to disconnect wheel speed sensors at each wheel and see if the speedometer settles back down. Reconnect the ABS module to the harness. Disconnect one wheel speed sensor at a time and reconnect if the speedometer stays stuck at 10 MPH. If you disconnect one and find the speedometer back at zero, leave that sensor disconnected and go for a test drive with everything else reconnected. If you regain normal driving AND your speedometer, that speed sensor you disconnected is shorted. It won't shut off the ABS light as you just created a new code by leaving a sensor disconnected. The ABS module can at least send valid wheel speed data to the cluster from the other three sensors.

There's always a chance that's an excercise in chasing your tail. I'd then, at least, look for the other end of the speed sensor connectors to have what's called a bias voltage. I can't provide any specs, but you can always use a little Sesame Street logic. Test for voltage across all four connectors; see if one of these things is not like the others. They may not have the same voltage across all four connectors. They should at least be the same from side to side. That assumes Toyota does run a bias voltage on the sensor circuits to detect opens. I'd also test the sensor wires going back to the module. This would be an OK place for an Ohm meter. Just test at each wheel speed sensor connector for unwanted continuity to ground.

After that, if you want to fire another module at it, it's not a terrible gamble. But eBay does make it more of a gamble. You're buying a used part that might also be a faulty part. Finding bad parts and trying to fix them with more bad parts makes you second guess yourself into unbridled confusion. The best I can recommend is that you look at the seller history for good feedback and see if used car parts are what the guy primarily sells. Outside of eBay, I'll let you do your own Googling on Toyota ABS module pattern failures. Try to find some valid concensus that ABS modules are a pattern failure part.

Having said that, can any owners of older Camrys on this forum speak to any repair history on their own cars that point at ABS module replacements?

 

 

you do not need a reflash and do not swap the whole abs module, there's like 4 screws that hold the electrical part to the hydraulic part. just swap the electrical part over. it works 100 percent as i have done this on countless 07 to 11 Camrys and Avalon's. plus you wont have to re bleed the brakes

 

That's my plan. Not much at risk. Thanks.

 

Speed sensor was always my first guess but all I did so far was a visual inspection. But that doesn't explain the lack of codes from the two fancy scanners. I did do voltage check on the pins of the ABS connector and found two of them had 12v (don't remember which two), one was ground and one showed nothing.

Anyhow, I ordered the used part understanding I may have wasted $86 dollars, and I'll give changing over the module part and see what happens. Should be here tomorrow. Meanwhile I'll do as many of the checks that you suggest as I can

I flew big jets for 36 years and you don't have to tell me how elusive troubleshooting can be. Incidentally, ECS was a warning light on 767 and my old brain substituted ECS for for CEL my first confused post

Can't thank you enough for your help.

 

But that doesn't explain the lack of codes from the two fancy scanners.

It happens more than you'd think. I'm happy for you that you've at least got a reasonable direction in your diagnosis.

 

I would check the resistances on the cable going the trans. probably at the module so you can test the cable also. What trans does this use...U151E?

 

I don't know trans designation. How is best way to determine? It's a US built 2004 3.0 XLE. Wouldn't they all be the same? When I changed the speed sensors, I discovered they were both on top of trans, one near the engine and one near the battery box. They were identical magnetic "plug-in" sensors. Does that tell you anything?

 

….I don't know trans designation. How is best way to determine?…

There should be a sticker/label on the driver side door with lots of info. on it, including the type of transmission the vehicle has.

 

Did you have a new battery installed? Check the ground cable from the battery to the body of the car To make sure it's tight. Any other work done on it recently?

 

Battery not new but normal voltage and powerful starts. No other work done recently. And like I said, this started after a normal local drive and sitting in a parking place for an hour. Came out and the warning lights were on and the car would not reverse and went only forward in first and second gear with speedometer stuck on 10 mph.

 

Problem SOLVED!! Many thanks to those of you who helped me work through this problem. I received the used ABS module I purchased on eBay to and transferred the controller to the valve body. Instant success. No lights and all functions and braking are normal.

It was not necessary to re-program the module as I feared, but I was able to obtain the exact part number from the exact model of car that I transferred to.

The saddest part of the story is that speaking with 5 different shops I got analysis so variable and all so wrong up to and including "need a new transmission and I'll put in a used one for $2400". In the end, the used part was $86. Of course, I did spend $21 for the VSS which didn't help. Anyhow, thanks again Toyotanation.

 

Don't thank us just yet. The bill is in the mail...😁

But seriously, I'm happy to hear you won.

 

Some final thoughts on problem solved. Looking back at the original faults, there were two keys that were not initially obvious. (1) the speedometer reading constant 10 mph any time the engine was on. (2) No codes showing with ABS and Brake light on.

The light bulb moment was when I disconnected the ABS module and found that the speedometer went to zero and the transmission and driveability went to normal. That indicated that somehow the ABS module was signaling the speed to the car at a constant 10 and that was preventing the transmission from up shifting. Another clue was that the lack of ABS codes meant that the ABS module wasn't communicating with scanner.

Anyhow, if you have been following, I purchased a used ABS module - exact part number from 2004 Camry V6 - and transferred the ABS electrical module to the brake pump assembly and the problem has been solved. A bonus being that the brake module did not require reprogramming.

Thanks again to those who helped along the thought process.

 

One more thought. This link to a video that shows exactly what I did to replace the ABS electronics.