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Air suspension anomaly

No hand held tester the spark used a £1200 laptop especially designed to use on car and hgv data.
He plugged his Bluetooth piece into the obd point and linked to his laptop.
He could control the cars height movement via his laptop very cool piece of kit.
Useless if you can't understand the data your looking for.
I bought new height sensors to replace my broke ones but it's not just a case of replacing they must be set other wise the car will just stay in neutral or go to its highest setting for safety mode.
It can be set by small movements with another person testing your height switch and plenty of patience.
Recently purchased a LC5 and have similar issues to you. I've downloaded the Toyota Techstream software, which also allows you to plug in the LC via OBDII and test the air suspension without pressing the buttons in the car!

Techstream reports a C1713 fault with the rear right sensor. So I tried measuring the sensor heights at engine start and then cycling through low, neutral and high. I understand that one of the values needs to be negative (-) and the other positive (+), but the values should be similar if you don't count the negative/positive sign.

I think my readings are all over the place, even when I turn on the engine, go to low setting, then back to neutral (which gives me the best ride comfort), the sensors report ~+100 mm lift, when it should be 0 at neutral? In the FSM documents Simon posted, it is stated: high should be +30mm, low should be -30mm, which makes me think neutral should be 0. Does anyone else know what the sensors should be reading out in Techstream?

I think I am going to replace the whole RR sensor unit... thought it arrived today but it turned out I had ordered the RL version...

See screenshots below for "RR Height Control Sensor" and "RL Height Control Sensor" readings and fault codes reported.

Fault code reported:


Low AHC setting:


Neutral AHC setting (after low pressed first):


High AHC setting, after low, then neutral:


Can you actually measure the height change relative to the ground?
Looking at the measurements (i never plugged mine in when repairing) they seem proportionate ie 100/side avg, in the manual there is a method to measure the actual resistance of the height control and set them that way, i guess its just a variable resistor reading that goes back to the ECU? i was wondering if the measurements in the ECU were calculated from the readings on the height control sensors but the units given are mm?

Judging by the autosparks Reading the ecu gets the reading from the height sensors.
Apparently each side goes to +or - 50 and are set around the 0 marker but plus or minus by 5 either side is acceptable apparently.
I ended up removing my system and replaced with coil springs.
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While cruising in Tuscany on a road/offroad muddy clay trip, car became more jumpy bumpy (national holiday day), so I stopped at first gas station to take a look,what is going on. Broken piece of height control.
First aid kit and after lunch ideas - zip ties! The ride was noticably better!
Next day after going north I checked at Toyota service in Modena, only one woman speaks english, got an invoice for 1000 eur, welding at spot not possible,need an appointment few day before,blablabla. So they cut my zip ties to check problem, photos were not enough, so at the and there was only one option, me under the car with three new zip ties.

While driving north I decided to check for 4x4 services,usually good people :) found one near Verona, 4x4 factory, with help of google translate,paper and pencil, work started.
Patient survived, 1k km later everything ok.

All thanks to the 4x4 factory, dissapointed with bureaucratic Toyota service.


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Sad to say, but that is becoming the norm for Toyota these days, disinterested or unable to carry out work satisfactorily. They care experts at lightening your wallet though, with some of the stories we hear.
Glad you found some competent people in the end with 4x4 factory.
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Air suspensions are incredible thing.... my Uncle has them on LC 120 Prado.... one day car lies on ass :) In the garage.... compressor worked... and tried to make them full - bags :) No leaking.....
when you get off the car, cars ass lies only on shock absorbers.... 1/2 year it worked :) compressor massive respect! ....... one day my uncle told me this....
so i found.... originals mega expensive, What a hell :) or you can try.... Arnott Arnott A-2949 - Vzduchová pružina, podvozek - [Leaving Land Cruiser Club]

Or wait a minute..... :) hey, what about check theeeese.......
Ohhhh so cheap.... but heyyyy,,,....... something cheeper from china can work better than originals.... you know originals are piece of shit! and so expensive.....

I have ordered them, installed to Uncles LC 120, and he is very happy..... problems with originals is solved.... no rust, the tube rusts, inside the bag-pipes- original..... tube is very xpensive :) So in this edition no rust, all plastic.... easy to change- plug and play..... question is how long it wil works..... MMMM :cool: Uncle is beta tester...... :) But after month he says it works just perfect...... hmmmmm :cool:

Some things from China are really better than originals Japan, few things.... maybe this is one of them :cool: I told my Uncle..... you are test mule..... OK??? ok!!!! i love it :)
I love mine chinese bag pipes :) they are perfect.... wow...

YENKEEE...... dooooodle man :cool:
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If anybody has referrences on these, write it.... I have to say it works absolutely great, we had to change this tube, total corrosion at bag contact....
48986-60020 uncle had to pay more for this pipe than for bags :) TUBE, HEIGHT CONTROL, NO.6
second pipe to another bag was not corroded.... hmmm okey :cool:

Compressor works perfect, all works perfect.... it is very difficult system, than springs :) but okey..... thanks china not loosing money :cool:

If i call uncle i say: " hi dooodle man.... how it works :) And He says perfect, absolutely perfect, so great than..... :cool:

But remember, you will need many o-rings, they are all defected.... I didnot understand that, there is only air in compressor, but o-rings are crushed.... after 14 years.... all..... !!!!!
So you need not only tube No6. but moment.... yes you need!!!! this
90301-04011 8x
48932-30010 4x
48934-30010 2x
So not only tube, also this :cool: 8 o-rings!!!!! they are all defected!!!!!.... after 14 years.... don´t understand why??? but it is like it is :) 4 plates and 2 clips

After that system works like a new :cool: car is jumping on air packs :cool: 200.000km since 2008.

So I hope it will help to some Prado 120 Rear Air suspensinsion users..... It was Expensive.... now it is cheap and funny.... :cool:
this price is incredible....
Yes it works :) people are worried only bcause low price :cool: lets risk it :) And no, I don´t work for this company.... I only like it, found it "so cheap and soooo good!!!! " :cool:

When I tested difference between standard coil suspension on mothers car and Uncles car with Air rear new china suspensions.... hmmmmm both are so much better than on any SUV.....
Air suspensions rear are little more comfortable, more.... when it works 100% ..... It is.... Land Cruiser is more jumping, pumping :) on bad roads....

It is little more comfortable :) but it was money dangerous system, now it seeems no problem costs same money as springs---- but it is soooo difficult system..... no I dont like it, i like springs :cool:
My mechanic told me, he is changing crushed springs.... I told him, you must be joking !!! :) I have never seen braked spring on japan car..... I changed only rear springs on Toyota Celica 1989, it looked like underwater coral island :) it was soooo crazy :) but it worked, I bought new springs and so on...... :) front springs there was no coral island.... destroyed springs on japan car???? nooooo possible.... german cars maybe and so on :)
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Why I say this.... this about a change, you don´t have to be worried about Land Cruisers with rear Air suspensions :) before YES, NOW NOT! It is not a money trap......from NOW....

And some snapshot..... hmmmm
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This is my favourite game monkey when I was young..... And this is her place.... she is sitting at subaru and checking what I drink :) she has a special control place :)
She checks me from behind.... :cool: this monkey is from 1980´s made Crazy model, not nose, but no problem :cool: you have to smile as you see it.... like celica :) YES
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Hey mother, clima okey??? Yeah---- goood.... hey monkey no problem :) no no problem :) so everything is just perfect :) hey dooodle man okey :) okey.... okey :cool:
For the last 2 months I've been told the air bags are faulty due to which it's deflated down turned out my vehicle donkey cart.. however, by the time I was searching for the parts usually drove it max 20km/h speed.. by chance thought to give a relief to the air compressor so turned off the AHC and after sometime noticed the vehicle is back to normal point.. even the pressure retained after 2 days in the parked vehicle.
Any idea what may cause it - may have something to do with loose wiring where at the same time rare brake light stopped working.
Thanks for the response @mwhtc

I'm wondering where comes the tie rod in this picture and how it's related with sensor thing?

Thanks again!
I'm not sure myself. From memory of the bit of an explanation I had is that it stops the suspension either going too tall or too small, and it can break so that the suspension has no real restriction in height.

That's only a guestimate though
OBD2 computer test may be of any help here? Well the mechanic points out the replacement of air balloons/bags as well as shock absorbers where I'm not convinced at all
I think in terms of the air bags it'll be fairly easy to see if they're knackered or not. Just stick your head under and have a look. Other way would be to stand at the back of the truck and see if you can hear the compressor engaging. If it is, and it's on for ages and nothing is happening, then the bags aren't holding air. If the compressor isn't coming on at all, then it's either broken or the sensors aren't working.

The OBD2 scanner probably won't do anything for the air suspension, you would need Techstream for that.
Thanks @mwhtc for the tip.

How to validate the sensors? What can be went wrong? Anything to do with wiring since at the same time one of the break light also malfunctioned.
Tell us more about the brake light fault. Have you checked the bulb and the fuses? Is it just one side and are the other lights ok?