Erratic deceleration on '12 LS460 L AWD
#1
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Erratic deceleration on '12 LS460 L AWD
Just bought a pre-owned 2012 LS 460L AWD with just over 50K miles on it. It's my third LS (all bought pre-owned), and it's head and shoulders nicer than my '90 and '99 LS'es (which I drove 310K and 270K miles in Houston traffic)!
After driving the "new" LS for about a month, it's clear there is something very strange going-on with the drive-train and/or brakes. Here's the symptoms...
1st problem...
At 60 mph, I let off the accelerator AND off the brake and let the car "coast down"... It slows down as expected until it gets to about 35 MPH, and then it feels as if I were applying brakes (even though I'm NOT). It slows down RAPIDLY between 35 to about 22 mph. Then at 22 mph it seems to "release" and the deceleration returns to a more gradual amount. It's almost like the transmission or drivetrain down-shifted into a lower gear between 35 and 22 mph (causing more deceleration) and then shifted into neutral at about 22 mph. However, I've watched the tach, and the engine revs don't indicate that the transmission has down-shifted. The engine revs remain at what you would expect for a car that's coasting to a stop. So whatever is going-on isn't "noticed" by the engine. And so I assume it's a problem in the transmission, diff(s) or even the brakes (even though I'm not applying the brakes).
2nd problem (maybe related to the 1st)...
When crawling along at 2 to 5 mph in very heavy stop-and-go traffic (a typical morning commute) it's almost impossible to come to a gradual, smooth stop. At very low speeds, the brakes seem to be "all off" or "all on".
Has anyone else seen these symptoms? I'm guessing that it's an issue with the AWD - maybe the "center diff" or something related. Either that, or the brakes are spontaneously applying themselves.
But is it a problem or simply part of the normal operation? And is there any additional/recommended service for the AWD, especially considering it now has 50K miles on it???
Thanks in advance!
DadCat
After driving the "new" LS for about a month, it's clear there is something very strange going-on with the drive-train and/or brakes. Here's the symptoms...
1st problem...
At 60 mph, I let off the accelerator AND off the brake and let the car "coast down"... It slows down as expected until it gets to about 35 MPH, and then it feels as if I were applying brakes (even though I'm NOT). It slows down RAPIDLY between 35 to about 22 mph. Then at 22 mph it seems to "release" and the deceleration returns to a more gradual amount. It's almost like the transmission or drivetrain down-shifted into a lower gear between 35 and 22 mph (causing more deceleration) and then shifted into neutral at about 22 mph. However, I've watched the tach, and the engine revs don't indicate that the transmission has down-shifted. The engine revs remain at what you would expect for a car that's coasting to a stop. So whatever is going-on isn't "noticed" by the engine. And so I assume it's a problem in the transmission, diff(s) or even the brakes (even though I'm not applying the brakes).
2nd problem (maybe related to the 1st)...
When crawling along at 2 to 5 mph in very heavy stop-and-go traffic (a typical morning commute) it's almost impossible to come to a gradual, smooth stop. At very low speeds, the brakes seem to be "all off" or "all on".
Has anyone else seen these symptoms? I'm guessing that it's an issue with the AWD - maybe the "center diff" or something related. Either that, or the brakes are spontaneously applying themselves.
But is it a problem or simply part of the normal operation? And is there any additional/recommended service for the AWD, especially considering it now has 50K miles on it???
Thanks in advance!
DadCat
#2
Pole Position
Hello Dadcat, congrats on your recent acquisition of a 4LS. Based on your experience with the LS, you have truly enjoyed the fruits of this highly reliable automobile. It would be great to see inside and outside pics of your car.
For the 1st "problem", my car has done that occasionally, as if it downshifted into too-low a gear while coasting, but it is so rare that I have not investigated it carefully. But your guess of a transmission issue seems reasonable. Maybe the system just needs an update. As for the 2nd "problem", are you saying the brakes are grabby? It is a common occurrence with this car, and takes some getting used to. Some folks have noticed that the grabbiness goes away after switching to Centric rotors.
Since you have a pre-owned (CPO?) car, just have the dealer take a look. It appears that you are experiencing these issues all the time, so they must be easy to replicate.
For the 1st "problem", my car has done that occasionally, as if it downshifted into too-low a gear while coasting, but it is so rare that I have not investigated it carefully. But your guess of a transmission issue seems reasonable. Maybe the system just needs an update. As for the 2nd "problem", are you saying the brakes are grabby? It is a common occurrence with this car, and takes some getting used to. Some folks have noticed that the grabbiness goes away after switching to Centric rotors.
Since you have a pre-owned (CPO?) car, just have the dealer take a look. It appears that you are experiencing these issues all the time, so they must be easy to replicate.
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Thanks! I looked for a CPO 2012 for a long time before I found this non-CPO at a Mercedes dealer. But I did buy a warranty, which should cover the repairs (unless it's brake pads). I'll give it a few months and then take it to a Lexus dealer and have them service the trans/diffs and look at the brakes. What are Centric rotors?
I wanted a 2012 because I'm not a big fan of the hour-glass grill they introduced in 2013 (not to criticize your 2014 - it's just a matter of tastes).
BTW: my 2012 is also Obsidian with Black leather. So I think we mostly have the same taste!
DadCat
I wanted a 2012 because I'm not a big fan of the hour-glass grill they introduced in 2013 (not to criticize your 2014 - it's just a matter of tastes).
BTW: my 2012 is also Obsidian with Black leather. So I think we mostly have the same taste!
DadCat
#4
Long shot, but is the car equipped with the pre-collision system or radar cruise control?
As to the braking, comotiger is right about the brakes being grabby. I remember when I took a test drive before I bought my car. My wife was in the back seat and she asked me why I was stomping on the brakes. I said I wasn't, its just that they were so much touchier than my Infiniti Q45a.
As to the braking, comotiger is right about the brakes being grabby. I remember when I took a test drive before I bought my car. My wife was in the back seat and she asked me why I was stomping on the brakes. I said I wasn't, its just that they were so much touchier than my Infiniti Q45a.
#6
Try bumping it into neutral just after lifting off the throttle and see if it still behaves oddly. That will narrow the issue down to brakes or driveline dragging vs. a transmission issue. Once that's determined, you will have more ammo to inform the technician where to look first.
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#8
Pole Position
Thanks! I looked for a CPO 2012 for a long time before I found this non-CPO at a Mercedes dealer. But I did buy a warranty, which should cover the repairs (unless it's brake pads). I'll give it a few months and then take it to a Lexus dealer and have them service the trans/diffs and look at the brakes. What are Centric rotors?
I wanted a 2012 because I'm not a big fan of the hour-glass grill they introduced in 2013 (not to criticize your 2014 - it's just a matter of tastes).
BTW: my 2012 is also Obsidian with Black leather. So I think we mostly have the same taste!
DadCat
I wanted a 2012 because I'm not a big fan of the hour-glass grill they introduced in 2013 (not to criticize your 2014 - it's just a matter of tastes).
BTW: my 2012 is also Obsidian with Black leather. So I think we mostly have the same taste!
DadCat
I wasn't a fan of the monster grille on the 2013+, but it has grown on me. In fact I had a 2012 SWB for several months before upgrading to the 2014 LWB for all the goodies (BSM, RCTA, DRCC, LKA, UltraLux...), some of which are not available pre-2013 (BSM, RCTA).
Welcome again, and look forward to the pics. Sounds like a great car and buy!
#9
I have the exact same car as you.
It's a know issue for the AWD manufactured in 2012. Those drive axles are not properly balanced, creating the vibration decelerating. You can test this by putting the car in neutral as it does it. If it disappears, you found it!
Both my front axles were changed under warranty. They fight it a bit, cuz it's a costly repair, but they will do it.
It's a know issue for the AWD manufactured in 2012. Those drive axles are not properly balanced, creating the vibration decelerating. You can test this by putting the car in neutral as it does it. If it disappears, you found it!
Both my front axles were changed under warranty. They fight it a bit, cuz it's a costly repair, but they will do it.
#10
I have the exact same car as you.
It's a know issue for the AWD manufactured in 2012. Those drive axles are not properly balanced, creating the vibration decelerating. You can test this by putting the car in neutral as it does it. If it disappears, you found it!
Both my front axles were changed under warranty. They fight it a bit, cuz it's a costly repair, but they will do it.
It's a know issue for the AWD manufactured in 2012. Those drive axles are not properly balanced, creating the vibration decelerating. You can test this by putting the car in neutral as it does it. If it disappears, you found it!
Both my front axles were changed under warranty. They fight it a bit, cuz it's a costly repair, but they will do it.
https://www.clublexus.com/forums/ls-...30-40-mph.html
My '13 vibrated significantly while decelerating at highway speeds. I had the front driver side axle replaced by the dealer under warranty. Smooth as silk now!
Last edited by droclex; 03-17-17 at 05:59 PM.
#11
Lexus Fanatic
As stated by others above, switching my rotors and pads to Centric premium completely eliminated my grabby brakes. They are now nice and linear and smooth.
Get a transmission flush from your dealer. It's good maintenance and the dealer can reflash your trans ECU at the same time.
Get a transmission flush from your dealer. It's good maintenance and the dealer can reflash your trans ECU at the same time.
#12
Racer
As stated by others above, switching my rotors and pads to Centric premium completely eliminated my grabby brakes. They are now nice and linear and smooth.
Get a transmission flush from your dealer. It's good maintenance and the dealer can reflash your trans ECU at the same time.
Get a transmission flush from your dealer. It's good maintenance and the dealer can reflash your trans ECU at the same time.
#13
Lexus Fanatic
Chris, I understand braking is smoother for those that went the Centric route. Why is that exactly? I can see how different composition can affect squealing and/or amount of brake dust, but how do different rotors and brake pads eliminate the grabbiness? I am glad it does, I just don't understand the why please.
#14
Intermediate
Chris, I understand braking is smoother for those that went the Centric route. Why is that exactly? I can see how different composition can affect squealing and/or amount of brake dust, but how do different rotors and brake pads eliminate the grabbiness? I am glad it does, I just don't understand the why please.
There's apparently also a "low dust" OEM pad option that would be easier on those negatives while sacrificing some of that grabbiness (aka effective braking force).
In my last few cars, I went to ceramic brake pad compound pads to chose a different set of compromises.
Ceramics tend to brake "smoother" and with less dust.
I've found that they tend to be noisier/grabbier when they're cold (as in winter cold).
That all goes away once you've done a bit of braking or once the engine heat has warmed the front end.
I've had my 460 a month now and can't wait to get the OEM pads out and some ceramics in.
Soon...
#15
Racer
As I understood it, the default OEM brake pads offer a "high friction" compound that's optimized for maximum braking. The tradeoff seems to be higher dust and noise, and at low speed, the grabbiness most of us despise.
There's apparently also a "low dust" OEM pad option that would be easier on those negatives while sacrificing some of that grabbiness (aka effective braking force).
In my last few cars, I went to ceramic brake pad compound pads to chose a different set of compromises.
Ceramics tend to brake "smoother" and with less dust.
I've found that they tend to be noisier/grabbier when they're cold (as in winter cold).
That all goes away once you've done a bit of braking or once the engine heat has warmed the front end.
I've had my 460 a month now and can't wait to get the OEM pads out and some ceramics in.
Soon...
There's apparently also a "low dust" OEM pad option that would be easier on those negatives while sacrificing some of that grabbiness (aka effective braking force).
In my last few cars, I went to ceramic brake pad compound pads to chose a different set of compromises.
Ceramics tend to brake "smoother" and with less dust.
I've found that they tend to be noisier/grabbier when they're cold (as in winter cold).
That all goes away once you've done a bit of braking or once the engine heat has warmed the front end.
I've had my 460 a month now and can't wait to get the OEM pads out and some ceramics in.
Soon...
I remember when ceramic pads were only on exotic cars. That was back in the 90s. It feels special putting ceramic pads on the LS, even if it's more commonly available now. I'll post back with my experience and hope it matches the positive experience you and others have had.
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