Air suspension and sport vs. comfort
04-24-17, 12:00 PM
#1
Lexus Test Driver
Thread Starter
Air suspension and sport vs. comfort
I've had my '08 LS L for about six months, and I still can't tell a difference between 'sport' and 'comfort' settings. I consider myself sensitive to vehicle changes, and the difference in the MRC system in the '05 Cadillac STS I used to have was, while not blatantly obvious, you could definitely tell.
Since getting the FakeStream, I've found the RR damper assembly has a fault in a sensor - Damping force control circuit code C1733. I'm almost certain it was the right-rear.
The thing is, the suspension's height is fine, though it does feel as if it's always on 'sport'. The ride definitely isn't as cushy as I expected, though the last LS I rode in was back in 1994, an LS400, which felt identical to a W126 Mercedes.
Sure, I've played with my suspension's height settings a little, but before I even considered the FakeStream, it felt like that switch wasn't connected to anything but the light in the instrument cluster.
I thought I could feel a difference on large suspension extension, freeway speed, 'humps', but only on rebound and even then, the difference might have been 5 MPH in speed.
Anyone know what this control circuit code means and if there is any way to remedy it (I'm really hoping the answer is not "a new damper").
Thanks!
Since getting the FakeStream, I've found the RR damper assembly has a fault in a sensor - Damping force control circuit code C1733. I'm almost certain it was the right-rear.
The thing is, the suspension's height is fine, though it does feel as if it's always on 'sport'. The ride definitely isn't as cushy as I expected, though the last LS I rode in was back in 1994, an LS400, which felt identical to a W126 Mercedes.
Sure, I've played with my suspension's height settings a little, but before I even considered the FakeStream, it felt like that switch wasn't connected to anything but the light in the instrument cluster.
I thought I could feel a difference on large suspension extension, freeway speed, 'humps', but only on rebound and even then, the difference might have been 5 MPH in speed.
Anyone know what this control circuit code means and if there is any way to remedy it (I'm really hoping the answer is not "a new damper").
Thanks!
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mckellyb (04-24-17)
04-24-17, 04:38 PM
#3
Agreed. Definitely noticeable.
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mckellyb (04-24-17)
04-24-17, 05:46 PM
#4
Lexus Test Driver
Found this:
C1733
DETECTION CONDITION
When either of the following is detected:
C1733
DETECTION CONDITION
When either of the following is detected:
- An actuator open-circuit signal is detected for at least 1 second when the actuator operates.
- An actuator short-circuit signal is consecutively detected 8 times when the actuator operates.
- Harness or connector
- Rear shock absorber control valve RH (Rear damping force control actuator RH)
- Suspension control ECU
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mckellyb (04-24-17)
04-24-17, 09:54 PM
#5
Lexus Test Driver
Thread Starter
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mckellyb (04-25-17)
04-25-17, 09:38 AM
#7
Likely the system will default to full-stiff mode when a fault is detected, as that is the safest setting for high-speed maneuvers. GM's Autoride electronic 2-mode shock system does this, as I've had an intermittent SERVICE SUSPENSION note in the display on my Denali for years and it rides noticeably harsher when the fault message is active.
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mckellyb (04-25-17)
Trending Topics
07-01-17, 04:01 AM
#8
Lexus Test Driver
Thread Starter
Update:
I removed the rear seat and moved the parcel shelf enough to gain access to the top of the RR strut.
Removed the damper actuator, put the 'new' one in its place. Hmmm, no change.
Must be the suspension computer...bummer.
I leave the rear seat out, go up front and take apart the passenger's side of the dash. Oh, there are different computers depending on the suspension (normal air vs. sport), and I bought the wrong one. Well, let me see if this changes anything.
Nope!
Okay...and why didn't I think of this, earlier?! Measure voltage at a corner you know works. Ah, 5.3V at every terminal save for the ground.
I check the RR...nothing at any terminal, and no continuity between ground and the chassis. Well...let's start tracing wires!
Tug...wiggle...tug...wigg...hold on. Oh, it's merely not latched at a connector.
/facepalm
I check it all one more time, sure enough, the code is gone, I verify the actuator works (the original one) with it off the strut, and it does. Turn everything back off, swap the computers back out, so I'm back to 100% original, and reassembly is the reverse of disassembly.
At least I fixed the glove box while I had everything apart.
And, OH!!!! This is how an LS is supposed to ride...not with the damping turned up to 17 all the time.
There are 17 different levels of damping, all independent of each other, and it's a trip to see what the car is doing via the Fakestream. At no time did I get any corner to '17', even on 'sport'. Think of '17' as the autocross setting.
YAY FOR PORPOISING!!!
Finally, it's cushy. Based on where the loose connection was, it's entirely possible that wire was never connected.
I removed the rear seat and moved the parcel shelf enough to gain access to the top of the RR strut.
Removed the damper actuator, put the 'new' one in its place. Hmmm, no change.
Must be the suspension computer...bummer.
I leave the rear seat out, go up front and take apart the passenger's side of the dash. Oh, there are different computers depending on the suspension (normal air vs. sport), and I bought the wrong one. Well, let me see if this changes anything.
Nope!
Okay...and why didn't I think of this, earlier?! Measure voltage at a corner you know works. Ah, 5.3V at every terminal save for the ground.
I check the RR...nothing at any terminal, and no continuity between ground and the chassis. Well...let's start tracing wires!
Tug...wiggle...tug...wigg...hold on. Oh, it's merely not latched at a connector.
/facepalm
I check it all one more time, sure enough, the code is gone, I verify the actuator works (the original one) with it off the strut, and it does. Turn everything back off, swap the computers back out, so I'm back to 100% original, and reassembly is the reverse of disassembly.
At least I fixed the glove box while I had everything apart.
And, OH!!!! This is how an LS is supposed to ride...not with the damping turned up to 17 all the time.
There are 17 different levels of damping, all independent of each other, and it's a trip to see what the car is doing via the Fakestream. At no time did I get any corner to '17', even on 'sport'. Think of '17' as the autocross setting.
YAY FOR PORPOISING!!!
Finally, it's cushy. Based on where the loose connection was, it's entirely possible that wire was never connected.
07-01-17, 05:49 AM
#9
Lexus Fanatic
God you got it fixed! I knew something wasn't right lol
07-01-17, 07:06 AM
#10
Racer
Update:
I removed the rear seat and moved the parcel shelf enough to gain access to the top of the RR strut.
Removed the damper actuator, put the 'new' one in its place. Hmmm, no change.
Must be the suspension computer...bummer.
I leave the rear seat out, go up front and take apart the passenger's side of the dash. Oh, there are different computers depending on the suspension (normal air vs. sport), and I bought the wrong one. Well, let me see if this changes anything.
Nope!
Okay...and why didn't I think of this, earlier?! Measure voltage at a corner you know works. Ah, 5.3V at every terminal save for the ground.
I check the RR...nothing at any terminal, and no continuity between ground and the chassis. Well...let's start tracing wires!
Tug...wiggle...tug...wigg...hold on. Oh, it's merely not latched at a connector.
/facepalm
I check it all one more time, sure enough, the code is gone, I verify the actuator works (the original one) with it off the strut, and it does. Turn everything back off, swap the computers back out, so I'm back to 100% original, and reassembly is the reverse of disassembly.
At least I fixed the glove box while I had everything apart.
And, OH!!!! This is how an LS is supposed to ride...not with the damping turned up to 17 all the time.
There are 17 different levels of damping, all independent of each other, and it's a trip to see what the car is doing via the Fakestream. At no time did I get any corner to '17', even on 'sport'. Think of '17' as the autocross setting.
YAY FOR PORPOISING!!!
Finally, it's cushy. Based on where the loose connection was, it's entirely possible that wire was never connected.
I removed the rear seat and moved the parcel shelf enough to gain access to the top of the RR strut.
Removed the damper actuator, put the 'new' one in its place. Hmmm, no change.
Must be the suspension computer...bummer.
I leave the rear seat out, go up front and take apart the passenger's side of the dash. Oh, there are different computers depending on the suspension (normal air vs. sport), and I bought the wrong one. Well, let me see if this changes anything.
Nope!
Okay...and why didn't I think of this, earlier?! Measure voltage at a corner you know works. Ah, 5.3V at every terminal save for the ground.
I check the RR...nothing at any terminal, and no continuity between ground and the chassis. Well...let's start tracing wires!
Tug...wiggle...tug...wigg...hold on. Oh, it's merely not latched at a connector.
/facepalm
I check it all one more time, sure enough, the code is gone, I verify the actuator works (the original one) with it off the strut, and it does. Turn everything back off, swap the computers back out, so I'm back to 100% original, and reassembly is the reverse of disassembly.
At least I fixed the glove box while I had everything apart.
And, OH!!!! This is how an LS is supposed to ride...not with the damping turned up to 17 all the time.
There are 17 different levels of damping, all independent of each other, and it's a trip to see what the car is doing via the Fakestream. At no time did I get any corner to '17', even on 'sport'. Think of '17' as the autocross setting.
YAY FOR PORPOISING!!!
Finally, it's cushy. Based on where the loose connection was, it's entirely possible that wire was never connected.
07-01-17, 07:23 AM
#11
Lexus Fanatic
Remember the system is active, so 17 separate settings the computer will determine at each wheel what level is needed based on mode and driving conditions. When you enter a hard turn the system may attribute 17 to the outside front, 15 to the outside rear to level out the lean. The damping rate is always changing per corner when the system is working properly.
That's the awesome thing about that sort of system, my coil springs for instance they have to engineer the struts, springs and static dampers to deliver a good ride/handling balance in all conditions which equals compromise. A good air setup doesn't have to compromise nearly as much because going straight it can be soft, and then the system will adapt when you brake, accelerate or turn firming up what needs to be firmed up. Pretty cool. I wish the damn thing were more reliable lol.
That's the awesome thing about that sort of system, my coil springs for instance they have to engineer the struts, springs and static dampers to deliver a good ride/handling balance in all conditions which equals compromise. A good air setup doesn't have to compromise nearly as much because going straight it can be soft, and then the system will adapt when you brake, accelerate or turn firming up what needs to be firmed up. Pretty cool. I wish the damn thing were more reliable lol.
07-01-17, 02:09 PM
#12
Lexus Test Driver
Thread Starter
FatherTo1, each damper has 17 different settings. The system must not have separate setting variables for both compression and rebound damping, but rather, 17 complimentary combos.
When I got to a nearby school parking lot, I opened up the laptop and played around trying to get any corner to '17' with the opposite one showing '1'.
Best I could do was '15' and '1'.
The difference in all of them being set to '17' all the time versus how it should be...I almost can't believe an OEM managed to get truly marshmallow-like cruising ride in the same suspension as one which would be harsh in a semi-aggressive, mid-size sport sedan.
SW15LS, what truly sold me on properly executed air suspension was driving an '05 Jaaaaag XJ Super V8.
It was super-smooth, cloud-like, going straight, however, on a wide street in an empty industrial area, going about 40 MPH, I tugged strongly at the wheel and the car stayed disturbingly flat and changed direction startlingly quickly.
When I got to a nearby school parking lot, I opened up the laptop and played around trying to get any corner to '17' with the opposite one showing '1'.
Best I could do was '15' and '1'.
The difference in all of them being set to '17' all the time versus how it should be...I almost can't believe an OEM managed to get truly marshmallow-like cruising ride in the same suspension as one which would be harsh in a semi-aggressive, mid-size sport sedan.
SW15LS, what truly sold me on properly executed air suspension was driving an '05 Jaaaaag XJ Super V8.
It was super-smooth, cloud-like, going straight, however, on a wide street in an empty industrial area, going about 40 MPH, I tugged strongly at the wheel and the car stayed disturbingly flat and changed direction startlingly quickly.
07-02-17, 01:08 PM
#13
Hearing these details make me almost regret not getting the air system. I think I was just turned off of the hype here how undependable they can be and the cost of them. Truth be told I kind of wanted the feature but, didn't want to deal with the wife when I had to pull $3500 from the accounts because of an issue like this.
When I shopped for my LS460L (had to be an L), 2 of them I took for a ride had Air but, one when I hit a pot hole in the test drive, it bottomed out. That scared me right away on the car. I did try different settings while on my 25 min, ALONE test drive on one of them, I noticed no change no matter what I set it at, so there must of been an issue.
Still glad you got it fixed and besides time, it didn't cost you anything. Love simple fixes...
When I shopped for my LS460L (had to be an L), 2 of them I took for a ride had Air but, one when I hit a pot hole in the test drive, it bottomed out. That scared me right away on the car. I did try different settings while on my 25 min, ALONE test drive on one of them, I noticed no change no matter what I set it at, so there must of been an issue.
Still glad you got it fixed and besides time, it didn't cost you anything. Love simple fixes...
07-02-17, 02:35 PM
#14
Lexus Fanatic
All in all I would take the air, but really the coil suspension rides very similarly, and the reliability headaches aren't worth it IMHO.
07-03-17, 09:05 AM
#15
Lexus Test Driver
Thread Starter
It's been about a week, and surprisingly, I leave it on 'comfort' most of the time. Totally soft, borderline-floaty ride. The middle 'normal' setting is okay, but typically, I want either as much isolation as possible, or I was tighter, sport-suspension.
In fact, I wish 'sport' were about 40% more aggressive than it is, but I now know how to fake it out, though it requires a few bolts and work underhood.
If you have air and want autocross-tight settings, do this:
Before starting the car after stopping and shutting off the engine, open the hood, remove the starboard (right, as you're driving) side of the underhood plastic cover, unbolt the gold-tone cover which covers the top of the strut (12 mm socket, I think), disconnect the electrical connector on the strut, done. The computer turns all of them to '17' when you come to a stop. I have to believe this is so the suspension is as stiff as possible in case of a hard launch.
The computer, by default, will not adjust any of the others, and the RF is easiest to access. You can put everything but the electrical connector back where it was and button things up.
It's very, very different. It was almost enough to put me off the car when I test-drove it, but I could see it was, if nothing else, going to be tauter and more-responsive than expected, which I'd rather have if given a binary choice of 'hard' or 'soft' suspension.
In fact, I wish 'sport' were about 40% more aggressive than it is, but I now know how to fake it out, though it requires a few bolts and work underhood.
If you have air and want autocross-tight settings, do this:
Before starting the car after stopping and shutting off the engine, open the hood, remove the starboard (right, as you're driving) side of the underhood plastic cover, unbolt the gold-tone cover which covers the top of the strut (12 mm socket, I think), disconnect the electrical connector on the strut, done. The computer turns all of them to '17' when you come to a stop. I have to believe this is so the suspension is as stiff as possible in case of a hard launch.
The computer, by default, will not adjust any of the others, and the RF is easiest to access. You can put everything but the electrical connector back where it was and button things up.
It's very, very different. It was almost enough to put me off the car when I test-drove it, but I could see it was, if nothing else, going to be tauter and more-responsive than expected, which I'd rather have if given a binary choice of 'hard' or 'soft' suspension.