2007 LC “VX” (2 Viewers)

[GTV]

I have to get this sorted today. Please help!

I first marked the fluid level on the reservoir. Truck was cold.
Unbolted the top link and confirmed the sensor arms were moving freely.
Reinstalled the links on the bottom of the slot (they were already very close to the bottom).
Extended the links about 1/4” on each side.
Took it for a short 5-10 minute drive. Still rides like crap.
Popped the hood, fluid level went up slightly, 1 notch or so.
Measured the front end height, it’s now about 22 1/2”, about 5/8” higher than it was before.
How can the fluid level go up and the truck raises?? How can I extend the links and the truck raises? This makes no sense.

I want to give AHC a chance but we are not off on the right foot so far
Going to try to read the sensor resistance next.

 

[GTV]

I’m good with mechanicals but electrically challenged, luckily my uncle is a retired electrician. The sensor plugs were easy to find, on the top of the fenders like @uHu said they would be.

The ohm meter is not registering anything on either sensor. The needle does not budge. What does this mean? Both sensors are bad?

 

[LndXrsr]

Sounds like a sensor issue as mentioned before. Could be one or both, usually just one unless you've got really terrible luck. Could try swapping front sensor bodies side to side and see what you get. If the sensors are causing a fault in the system and AHC is not working, the TEMS (damping control knob, Comfort-Sport) may also be deactivated leading to the least damping and giving you that "pogo-stick" feel. Also, if the AHC reservoir is low, there's a chance the PO sucked some air into the system which could mess with all of this.

I know you're not in a position to do so right now, but the truck really needs a fluid flush and measurements with Techstream or equivalent. You could try to find someone in the area who has one of the more advanced generic OBDII readers and see if you can get access to the AHC channel readouts (pressure, height readings, etc). If you could get that info, you could diagnose a sensor issue much more easily and try to make your trip manageable.

 

[FxFormat]

AHC Pogo stick might be sign of bad accumulators, are you able to read the neutral pressures at all? You'll need techstream or try to find a repair garage with one of these Matco Maxo scanner, that's what we use at my shop and it's able to read Neutral pressures and all that AHC related stuff.

As for dog smell, the molecules are embedded into the fibers, you'd have to pull the entire carpet outside of the vehicle and give it a good shampoo, i used a Bisel deep cleaner and it got the smell out of my last LC.. Good luck, truck looking good, these little things are what comes with the purchase, i've never bought a used car that didn't need something done.

 

[LndXrsr]

There are a few devices that can read AHC info besides Techstream. Most common that I've seen are iCarsoft, OBDLink and VGate. Might check a local AutoZone or similar to see if their reader can get you any info. Sunday won't get you many shops or dealers available.

 

[A LEXUS BLEDEL]

Your next step is an AHC flush, it' $75 in fluid and about 30 min to an hour in time. Not really much else you can do until you diagnose all components of the AHC starting with the cheapest as well as most likely culprit. You'll just need to drive it as is until you can get fluid and flush the system properly and then you can accurately determine the next steps.
AHC is worth keeping as long as all globes/ accumulator/ AHC pump work. That is all dependent on the quality of the suspension fluid.

 

[GTV]

I appreciate the advice so far! I don’t have techstream yet. Silly me I thought I could get this thing home without it

I came across this thread and decided to run another test.

Long story short when I unplug the drivers sensor nothing changes. When I unplug the passenger side sensor the front end slams down nearly to the bump stops. That tells me that the drivers sensor is bad (please correct me if I’m wrong). I repeated this test multiple times, consistent results. Even slammed to the ground the ride quality was drastically improved. Fluid level went up above the full mark, this tells me that the system should have enough to function, at least until I get it home. I’d have to search the thread again but I believe 2001LC did a full fluid flush about 35k miles/2 years ago. Should it need it again?

Anyway we decided to try the ohmmeter test again because we weren’t confident with the results we got the first time. This time around the drivers side showed much less resistance than the passenger side (roughly 3k ohms on the drivers side and 8k on the passenger). We don’t know exactly what to make of that, please advise.

At any rate I decided to remove the drivers sensor and inspect it. Everything looked perfect inside so we made sure it was clean and put it back together. We tested resistance again at the sensor and we got the same low (3k-ish ohm) readings.

Reinstalled the sensor and went for a drive. The AHC light moved from N to L (first time I’ve seen it do that!) and the ride quality was very much improved. Not as good as I would expect AHC to ride but definitely tolerable. When I returned I measured the front end at 22”. Still much too high, especially for “Low” mode. Fluid level was below the line but higher than it was in the beginning.

Being that the thing now has an acceptable ride quality I’m tempted to leave tomorrow morning as planned. If it starts acting up I can try to find a sensor and swap it out... if that is indeed the issue. What do you think?

 

[LndXrsr]

Curious how you assessed the "ride quality" in L as the truck should go back to N at speeds above 5mph or so. Was the ride quality also improved as it transitioned back to N during your test drive as well? Did it go back to N while driving at all? Remember that transitions between heights can only happen with all doors closed, parking brake off, and foot off the brake pedal (or at least brake pedal held <5 seconds). Sometimes the AHC can get stuck "between" positions where the pressures and heights may be odd if something like a door sensor switch is malfunctioning. Just another thing to look into.

If the truck is back in N and the ride quality acceptable, you can probably make it back west, though reliability of the AHC moving between levels will be suspect until you can do formal measuring, troubleshooting and tweaking.

 

[GTV]

Curious how you assessed the "ride quality" in L as the truck should go back to N at speeds above 5mph or so. Was the ride quality also improved as it transitioned back to N during your test drive as well? Did it go back to N while driving at all? Remember that transitions between heights can only happen with all doors closed, parking brake off, and foot off the brake pedal (or at least brake pedal held <5 seconds). Sometimes the AHC can get stuck "between" positions where the pressures and heights may be odd if something like a door sensor switch is malfunctioning. Just another thing to look into.

If the truck is back in N and the ride quality acceptable, you can probably make it back west, though reliability of the AHC moving between levels will be suspect until you can do formal measuring, troubleshooting and tweaking.

Ride quality before was bad. Really bad. Almost as if the shocks were solid rods.

According to the instrument panel it stayed in L for the entire duration of the drive.

 

[LndXrsr]

Definitely not a good thing, staying in L on its own. Your AHC is likely in failsafe mode, suggesting pressures are too far off to function properly, likely pressures too high. Have you been able to get it back up to N? Not safe to drive in L for long distances.

 

[FxFormat]

Find 30mm and a breaker bar and turn both of the torsion bar adjusting bolt clockwise about 6 full turns each and see if that'll alleviate some of the pressure

 

[GTV]

Definitely not a good thing, staying in L on its own. Your AHC is likely in failsafe mode, suggesting pressures are too far off to function properly, likely pressures too high. Have you been able to get it back up to N? Not safe to drive in L for long distances.

It’s only in L according to the light on the dash. Hub to fender lip is still 22”, pretty high. I just took it for another drive, got up to 45mph and it stayed in L- according to the idiot light on the dash.

How far can I safely extend the links? I feel like that is probably what has made the ride better, if I can go further I will.

I haven’t dared touch the AHC control since I got the ride quality to be tolerable. It has also been in comfort mode the entire time.

I guess I gotta find someone with techstream or something similar. F’ing frustrating.

 

[GTV]

Find 30mm and a breaker bar and turn both of the torsion bar adjusting bolt clockwise about 6 full turns each and see if that'll alleviate some of the pressure

Just to confirm, will that raise or lower? I need to go down.

 

[FxFormat]

Just to confirm, will that raise or lower? I need to go down.

It won't raise or lower the ride physically, what it does is load up on the torsion bar's stiffness and alleviate the pressure that the accumulators has to take on during rebound/compression. It might absorb some of the harshness, but this is a shot in the dark unless you know what the neutral pressures are.

 

[GTV]

It won't raise or lower the ride physically, what it does is load up on the torsion bar's stiffness and alleviate the pressure that the accumulators has to take on during rebound/compression. It might absorb some of the harshness, but this is a shot in the dark unless you know what the neutral pressures are.

Ahh right, of course. At this point I’m tired of taking shots in the dark, I want some results.

 

[LndXrsr]

Ahh right, of course. At this point I’m tired of taking shots in the dark, I want some results.

Agree that tightening the torsion bars might work, but is indeed a shot in the dark without pressure readings.

At this point if you want results, you’re going to need some data. And if you want data, you’re going to need a reader device of some sort. Can only provide so much advice over the internet without those details.

 

[GTV]

Thanks for all your help guys. Sorry if I’m coming off like a little bitch. I wasn’t expecting perfection but I was expecting less trouble than this.

I’ll stay put for another day and try to find some data.

 

[LndXrsr]

Sounds like you have a long drive ahead of you and better safe than sorry. Don't want you or that unicorn getting mangled out on the open highway.

 

[uHu]

I appreciate the advice so far! I don’t have techstream yet. Silly me I thought I could get this thing home without it

I came across this thread and decided to run another test.

Long story short when I unplug the drivers sensor nothing changes. When I unplug the passenger side sensor the front end slams down nearly to the bump stops. That tells me that the drivers sensor is bad (please correct me if I’m wrong). I repeated this test multiple times, consistent results. Even slammed to the ground the ride quality was drastically improved. Fluid level went up above the full mark, this tells me that the system should have enough to function, at least until I get it home. I’d have to search the thread again but I believe 2001LC did a full fluid flush about 35k miles/2 years ago. Should it need it again?

Anyway we decided to try the ohmmeter test again because we weren’t confident with the results we got the first time. This time around the drivers side showed much less resistance than the passenger side (roughly 3k ohms on the drivers side and 8k on the passenger). We don’t know exactly what to make of that, please advise.

At any rate I decided to remove the drivers sensor and inspect it. Everything looked perfect inside so we made sure it was clean and put it back together. We tested resistance again at the sensor and we got the same low (3k-ish ohm) readings.

Reinstalled the sensor and went for a drive. The AHC light moved from N to L (first time I’ve seen it do that!) and the ride quality was very much improved. Not as good as I would expect AHC to ride but definitely tolerable. When I returned I measured the front end at 22”. Still much too high, especially for “Low” mode. Fluid level was below the line but higher than it was in the beginning.

Being that the thing now has an acceptable ride quality I’m tempted to leave tomorrow morning as planned. If it starts acting up I can try to find a sensor and swap it out... if that is indeed the issue. What do you think?

Re measuring sensors:
At the plug at the top of the fender, pin 1 (top left if you look at the holes/contacts with the lock at the top) is the center of the potentiometer, and should have half of the total resistance at N height. The total resistance is somewhere between 4 and 5 kOhm between pins 2 and 3. 8 k Ohm is probably too much and translates to a bad sensor, corrosion or wear. So, at Normal height, you should see nearly the same reading at pins 1-2 as at 1-3, somewhere between 2 and 2.5 k Ohms.

You opened up the left sensor, but suspected the right sensor. Now you know what a good sensor looks like, maybe check the right hand side as well?

For adjusting height, you have to shorten extend the link for lowering the height. (at the rear you move the link down in the slot to lower it).

There is a new post with good pics of sensors and links in the huge ahc-thread, here.

 

[GTV]

Re measuring sensors:
At the plug at the top of the fender, pin 1 (top left if you look at the holes/contacts with the lock at the top) is the center of the potentiometer, and should have half of the total resistance at N height. The total resistance is somewhere between 4 and 5 kOhm between pins 2 and 3. 8 k Ohm is probably too much and translates to a bad sensor, corrosion or wear. So, at Normal height, you should see nearly the same reading at pins 1-2 as at 1-3.

@uHu That is very helpful, we may take some more readings. Thank you!!

You opened up the left sensor, but suspected the right sensor. Now you know what a good sensor looks like, maybe check the right hand side as well?

Correction, when unplugging the drivers (left) side sensor there was no change, the suspension only responded when I unplugged the right side sensor. So I assumed the left sensor was the one at fault, we removed and inspected it.

For adjusting height, you have to shorten the link for lowering the height.

Are you certain about that? My friend sent me pics of the links on his lifted 2002 LX with 34’s and they are very short.