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Regen brakes don't work anymore!

Old 11-01-17, 07:36 AM
  #16  
MikePalm
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The slip light has started flashing quite often while stopping regularly. The switching between regen brakes and normal brakes will happen several times per stop.

They opened a new Lexus about an hour away so I decided to give them a shot. They said my front left ABS ring is cracked and it will cost about 1200 dollars to replace.

I will gladly pay if this will fix all the braking problems. I'm just worried it will only fix the slip light flashing problem which activated the abs.

Anyone here think I should not have them do this?

Last edited by MikePalm; 11-01-17 at 07:39 AM.
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Old 11-01-17, 07:04 PM
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Your in Sweden, here in the states we have many small auto repair places that specialize in foreign cars, like the Toyota/Lexus. I have found their labor rates to be much lower than the dealer. When working on my car they only use Lexus parts. You are going to be spending quite a bit more I would think having the dealer work on the car. I would look for someone other than the dealer for repairs like you need. Just my opinon.
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Old 11-02-17, 09:00 AM
  #18  
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A bad abs ring will cause the electronic brakes to be very confused. You will need to fix just to troubleshoot any braking issue.

ABS ring is part of the axle half shaft. Just order a $110 rebuilt shaft and have any shop install it. https://www.ebay.com/itm/Cardone-Ind...UdJ3sQ&vxp=mtr
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Old 11-02-17, 03:03 PM
  #19  
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Yep, there is no such thing as ABS ring replacement. Especially, for $1200. It's pasturing on ignorance.

I just wanted to mention something. BRAKES as such have nothing to do with regeneration. brakes are identical to conventional hydraulic brakes. All regeneration is done in PSD - Power Split Device. Easy way to check if regeneration works is to roll downhill or under momentum and toss gear shifter into B mode. Needle should drop down into charging area and stay there for some time.

What OP experienced sounded like air in ABS block or in brake booster/actuator. If there was a mechanical issue, like a bad ring or, even more common, dirty ABS sensor, surely, it will prevent normal ABS module function and confuse ECM to place PSD into regenerative mode or not. To be honest, I am not even sure how a solid metal excitor ring, aka ABS ring, hidden inside the hub, can get damaged. Now, dirty it gets easy. So do ABS sensors heads. They are very easy to get out and clean.
That said, keep in mind that brake system on those cars can be bled ONLY with Techstream scanner employed. ONLY. Brake booster pump, actuator and ABS block components must be moved by scanner in order to bleed air out.

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Old 11-04-17, 07:46 AM
  #20  
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I will try to find a rebuilt or used axle here and have an independent shop put it in. I will report back here to let everyone know if it fixes the problem. Thanks!
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Old 11-04-17, 02:19 PM
  #21  
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Why? New axle is $107 Amazon. I have driver side one coming Tuesday. With warranty and all that.
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Old 11-08-17, 03:14 PM
  #22  
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Once the Legal Team at Lexus HQ chokes over hearing that their representative told you “...that "its an old car" and "its good enough to just have the regular friction brakes for now"...” — you may get a sheepish call from someone with some brains that your hybrid system may be at fault.

Note that the hydraulic brakes and the regeneration (of kinetic energy back into the Traction Battery) are deeply related - and one does not and cannot be allowed to simply work singularly. Here’s an example of the Toyota/Lexus ECB-R brake and Regeneration contribution for a normal stop:




And here’s an example of a more aggressive stop:






OPERATION DESCRIPTION according to Toyota:

(a) ECB (Electronically Controlled Brake):
The skid control ECU receives signals from the pedal stroke sensor, master cylinder sensor and wheel cylinder pressure sensor. Based on these signals, the skid control ECU calculates necessary braking force for each wheel. The necessary hydraulic pressure braking force signal is sent to the hybrid control ECU via CAN communication. The skid control ECU receives a braking force (regenerative braking force) signal from the hybrid control motor via CAN communication. The ECU calculates the necessary hydraulic pressure braking force based on the necessary braking force and regenerative braking force.
Necessary hydraulic pressure is supplied to each wheel by adjusting the brake accumulator (hydraulic pressure source) pressure with each solenoid valve. If there is a problem with the braking function, the normally operating parts will maintain brake control as a fail-safe.

(b) ABS with EBD and Enhanced VSC:
The skid control ECU receives a vehicle speed signal from each speed sensor and detects wheel's slip condition and then sends a control signal to the solenoid.
The solenoid valve controls each wheel cylinder's hydraulic pressure and optimizes hydraulic pressure allocation to each wheel cylinder.

(c) BA (Brake Assist):
The skid control ECU receives the brake pedal stroke sensor signal and hydraulic pressure signal from the master cylinder pressure sensor and determines whether brake assist operation is necessary or not. If it is determined that brake assist operation is necessary, the ECU changes target hydraulic pressure applied to each wheel.

The following table further illustrates the total interdependency of the Hybrid and Skid control ECU's:



You may wish to argue that it is unsafe to drive the car when it is not working as designed.

Last edited by NateJG; 11-08-17 at 07:58 PM.
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Old 11-11-17, 03:33 PM
  #23  
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Thank you for the great info on your reply NateJG!

It makes me even more annoyed at the dealership I took it to first. They kept saying that the regenerative brakes don't matter and its perfectly safe without them. And they were also 100% sure the ABS was working fine...with a broken abs ring, haha.

I mentioned to the person at Lexus Sweden headquarters that if my car crashes with my 2 small kids in it that probably wouldn't be too good for lexus in court. He said he is not a mechanic but he will trust the dealer who said the car was just old. Unlike the good old USA, companies are not very scared by legal action here, probably because the courts are much more reasonable here.

The new axle is on its way from the states (could not buy a remanufactured cv shaft here, only lexus' $800 one) and will be installed December 22nd. I will report back then.
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Old 12-21-17, 11:49 AM
  #24  
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Default Problem fixed

Got the new axle installed and everything is back to normal. Very disappointed with the Lexus dealer that told me there was nothing to do about it. But happy that it's finally fixed now.

Thank you to everyone that contributed to try to help me along the way. Much appreciated!
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Old 12-24-17, 07:42 PM
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Thanks for posting the follow-up.
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Old 05-17-18, 01:57 PM
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Hi. Can you please tell me the exact piece you exchanged?
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Old 01-12-19, 03:42 AM
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MikePalm Again, i insist : Can you please tell me the exact piece you exchanged? I have exactly the same problem with my Highlander 2008 , I want to fix it. Thank you.

Last edited by kye04; 01-12-19 at 03:47 AM.
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Old 01-12-19, 07:46 AM
  #28  
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Originally Posted by kye04 View Post
MikePalm Again, i insist : Can you please tell me the exact piece you exchanged? I have exactly the same problem with my Highlander 2008 , I want to fix it. Thank you.
I have been having a similar issue in my rx400h. MikePalm has not been on the forum since 2017. A little googling shows he is a swedish-american basketball player, but I don't see him on any other forums so I can't reach out to ask if his problems are still resolved. Anyway, he states that the dealer said the ABS ring was cracked. smassey321 then pointed out the ABS ring is part of the axle half shaft, a ~$110 part. MikePalm says in his last post that he replaced the axle and the car is back to normal now.

So it would seem the ABS ring was in fact the fault causing little/no regen braking issue, did not throw any codes or turn on any warning lights, and the solution was to replace the ABS ring via a new half shaft axle.

that being said, you should inspect your ABS rings if possible to find which one has potential damage.

Last edited by mnewxcv; 01-12-19 at 07:49 AM.
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Old 01-12-19, 03:44 PM
  #29  
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@mnewxcv THANK YOU for your reply. I will look into this. Please tell me something : you said in the beginning of your replay , i quote" I have been having a similar issue in my rx400h " .
How did you fixed that ,the same way , replacing half shaft axle ?
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Old 01-12-19, 05:11 PM
  #30  
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Originally Posted by kye04 View Post
@mnewxcv THANK YOU for your reply. I will look into this. Please tell me something : you said in the beginning of your replay , i quote" I have been having a similar issue in my rx400h " .
How did you fixed that ,the same way , replacing half shaft axle ?
I haven't fixed it yet. I have gotten used to it to be honest. I looked at some data from Techstream on a short drive today and didn't notice any discrepancy between my 4 abs sensor speed readouts, however the polling rate was like 4 seconds. I may try cleaning all the sensors to see if that helps anything.
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