Originally Posted by HtownBlue

The brand of the scanner is Creader or Cread@r VII by Launch. I think that's the brand. That's what the box says.

Originally Posted by engin_ear

Something definitely bothering me about this solution. i currently have the same problem, rear left wheel. Found metal filings all over the sensor outside, and inside when i removed it as well. Cleaned it off, no difference.

The only ways this proposed solution can be effective is:
A) if the sensor has lost some magnetism and therefore needs to be moved closer to the tone ring - but doesn't seem like there's much clearance there. New sensors should clear up that problem, if that were the case, and all reports are that they do not.
or:
B) If the tone (reluctor) ring has been worn down abrasively. This is where the teeth are worn and not as high, so the signal magnitude is less. This seems to be the issue in my case - hence all the metal filings.

I'm going to replace bearings and axles at 168,000 miles anyway, and see what happens.

It's not clear to me why a new sensor would need to be filed and moved in closer to the ring, unless one or both of them is old/worn.

Originally Posted by HtownBlue

Situation and background:

2.5 YEARS AGO....Yes 2.5 YEARS AGO....in a far far land somewhere in Texas.....

I replaced my front bearings. During this procedure I obviously disconnected the entire front end including the ABS/Speed sensor on the front of the car.
Bearings eliminated the noise (whomp whomp whomp sound) issue I was having. But strangely another enemy entered my story. The day after I reassembled everything, I noticed something very odd.

When coming to a stop, while slowing down, and under 4 mph just as the vehicle was coming to stop the ABS WOULD ACTIVATE AND THE PEDDLE WOULD FLUCTUATE etc. The vehicle would come to stop of course normally, but the ABS would activate prematurely. It would flutter ONLY AT VERY LOW SPEEDS WHEN COMING TO A STOP, usually after driving at normal speeds such as coming to stop signs and lights.

Strange. So I take off speed sensors in front and clean them and make sure they are bolted on properly. Thinking this would solve problem.....but no. Still there.

So I thought maybe when I was disassembling the front hubs etc. I damaged the sensors. So I purchased NEW SENSORS and thought, bam, this will solve issue. NOPE. The enemy is still present and causing mayham.

So at this point I am at a loss. Not sure how to solve this issue. So I live with this inconvenience of the ABS consistently activated when coming to a stop but only at very slow speeds.

Finally after about 8 months I say screw it I will take it to the dealer to have them steal my money and tell me it was something stupid. So they check it out. They say sensors are all reporting data and that I have an issue with the ABS module. That makes zero sense because the ABS module is ONLY ACTIVATED WHEN THE SYSTEM TELLS IT TO. NOT TO MENTION THE ABS MODULE WOULD NOT BE WORKING AT ALL. OH mine was working all right. TOO OFTEN. And quite well. So I tell the dealer to screw off and they don't know what they are talking about. Enemy still plagues me for another 4 months.

After some research I discover that it could be the TONE RING which looks like a hollow gear on the axle that fluctuates the magnetic signal on the sensor. This "on and Off" fluctuation of the magnet on the speed sensor and how quickly it happens determines the speed reading. So it makes sense how this could somehow be the issue. That said, I have ZERO DESIRE TO REPLACE MY AXLES at the moment. That is a B*&^CH of a job.

4 more months go by. And guess what....the enemy is still there and as fate would have it I have to replace the axles due to CV clicking and vibration upon acceleration at high speeds.
F&*K!!! I do not want to do this job. Absolute nightmare of a job, but the bright side is that I would have BRAND NEW TONE RINGS ON BOTH FRONT AXLES. This will surely solve my abs/speed sensor problems! The Enemy will finally lose!
Except he didn't. After hours of pain removing the passenger side axle, and replacing, the new tone ring DOES NOTHING DIFFERENT. GRRRR..

Now I am stumped. another 4 months. Same garbage. Then I read that some parts manufactured in Asia for Lexus could have bad wiring in them. So I buy new sensors AGAIN. I knew I was wasting my money but hell, at this point I just want the damn thing working right. New sensors.....AND FAIL!!!! Nope. Still there.

So back to ANOTHER DEALER. They tell me that everything is normal and they cannot find out why it is doing what it is doing. They offer to so kindly replace my entire system for 2500 dollars. Oh how nice of them. They don't know how to fix it but will gladly take my money. Umm nope.

So now I am pissed. 4 months pass again. I read that I can buy a scanner system from China that will read nearly every sensor and system that Lexus has. It is only made in China because of licensing issues, but will read and communicate with my system almost identical to the 5000 dollar Lexus / Toyota Dealer Scan Computers. So I order it. But takes a while to get in.
2 months pass and it arrives. This machine is awesome. I can read data off almost every sensor in my vehicle and LIVE DATA AT THAT. I can read and erase ABS codes which standard scanners cannot do. I can read AC codes and sensors. This machine is legit!
That said I am able to pull up all 4 abs/speed sensors and view there live data. The actual readings they are giving out at that moment. So I go for a drive.....

Here is what I find. All 3 of my sensors are operating normally. My front right wheel however is not. As I approach 3.5 MPH or below it suddenly drops to 0. NO MPH while the others remain at 3...2....1 etc. as I decelerate.
SO I FOUND THE CAUSE. YAY right? Wrong. I have already replaced this sensor twice. I know I have a working sensor because it gives me readings at higher speeds.

WTH man!!!???? So from this point I hit the books. I read anything and everything about ABS sensors. You have active sensors and passive sensors. Active sensors read speeds at low MPH while passive usually do not read below 5 or 6 MPH. I'll save you the entire lessons. I learned a ton. I know exactly how these systems work and how they make the brakes fluctuate and flutter and why they do. All this knowledge but still no way to defeat my enemy.

Now I research some more. I find that some people have encountered similar issues in other vehicles when the sensor either became loose or for whatever reason was not mounted properly. But mine were mounted properly and tight. I promise. BUT......there is a reason that people would have that issue. These sensors can be very very sensitive. And if there is junk on the sensor, or if the sensor is out of place it will give off bad readings. Active sensors are even more sensitive.
So why is my sensor acting up? Well it turns out that the distance between the sensor and tone rings can effect output sensitivity. Maybe this is the issue.

But how on earth do I bolt the sensor closer to the tone ring on the axle when it bolts flat onto the knuckle housing? It has 1 10mm bolt that holds it in place while the sensor portion inserts into a hole that exposes the tone ring on the axle.
The only way to get the sensor closer to the tone ring is to manually file down the seating edge of the sensor where it contacts the knuckle. This will effectively make the sensor "longer" as the sensor will protrude through the hole further seeing as the the seated edge was filed down approximately 1 mm. Thus making the sensor 1mm longer.

So I take off sensor from knuckle. File down the entire seated edge along with the edge that goes around the cylindrical sensor portion. This in turn places the magnetic sensor closer to the tone ring. Bolt back in.

Hooked up fancy all knowing Chinese scanner and bring up all wheel abs sensors on my live data feed. Go for a drive. As I slow to stop at a light I watch the sensors. All 4 read: 6.......5........4.......waiting for abs activation.....BUT NO.......3......2.......1.......0!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

VICTORY!!!!!! I drive around in celebration trying to get the enemy to come back and show himself! NOPE. HE GONE!!!! And so is my ABS premature activation issue.

BOOOOOM!!!!! I win. HE loses. GAME OVER!!!!!

Originally Posted by Santi10

I am having the same problem. Brought my GS350 to the Lexus dealer and they said that I needed all new rotors and brake pads, which by the way were replaced 15 months ago. One of the reasons that I will not buy another Lexus.