Land cruiser 100 AHC problem (2 Viewers)

Joined
Mar 31, 2019
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13
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Malaysia
Hi all,

Lately i have problem with my AHC suspension. I can go up and down between Low and Neutral. But not able to go from Neutral to High. After i press the H button, it blink for few seconds then stop blinking.
I also found out that the suspension is very stiff. When the car landing down after going through road bump, i can noticed vibration to the suspension. It make no difference when twist between comfort and sport setting.
Last time when i put my gear to P, suspension behind will raised but now no more. I also noticed both front and rear of car are lower like sagging.
So what is the problem with my suspension? How to diagnose to find out the cause? Really appreciate guidance from you all. Thanks
 
Joined
Mar 28, 2006
Messages
294
Location
Upstate NY
Hi all,

Lately i have problem with my AHC suspension. I can go up and down between Low and Neutral. But not able to go from Neutral to High. After i press the H button, it blink for few seconds then stop blinking.
I also found out that the suspension is very stiff. When the car landing down after going through road bump, i can noticed vibration to the suspension. It make no difference when twist between comfort and sport setting.
Last time when i put my gear to P, suspension behind will raised but now no more. I also noticed both front and rear of car are lower like sagging.
So what is the problem with my suspension? How to diagnose to find out the cause? Really appreciate guidance from you all. Thanks

First of all do the graduation test, namely the number of marks on the fluid level between high and low. Likely, the truck needs new globes front and rear.
 
Joined
Mar 31, 2019
Messages
13
Location
Malaysia
First of all do the graduation test, namely the number of marks on the fluid level between high and low. Likely, the truck needs new globes front and rear.
I only able to go from low to neutral. Can be consider in checking the graduation? The globe is just replaced year ago.
 
Joined
Dec 6, 2016
Messages
249
Location
Brisbane, Australia
I only able to go from low to neutral. Can be consider in checking the graduation? The globe is just replaced year ago.

So we can start to help and just to be clear about your situation -- please confirm that you replaced all four 'globes' (also called 'Gas Chambers') about one year ago? The 'globe' is the large black item in the first picture -- mounted on the chassis rail near each wheel, so four altogether. The front 'globes' are slightly smaller Also, was the AHC fluid replaced with genuine Toyota AHC Fluid at the same time as the 'globes' were replaced? Is the level and colour of the fluid in the AHC Tank similar to the second picture? Can you please confirm that no other kind of fluid was used in the AHC system?

In addition, can you please advise the year of manufacture of your Landcruiser? This will be found on a label -- either in the engine bay or on the pillar between the front door and the rear door. Left Hand Drive or Right Hand Drive? How is the condition of the vehicle underneath? Does it have much rust?

Also, do you have Techstream? It will be needed for diagnosis. See details at this link:



Toyota RR Globe or Gas Chamber.jpg


AHC Tank.jpg
 

LndXrsr

AHC Aficionado
SILVER Star
Joined
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Messages
279
Location
Cincinnati
Can’t do a proper graduation test without being able to go into high. Most common culprit is hydraulic pressures are too high in the system to safely raise into high (where AHC pressures are the highest and the least weight is on the torsion bars/springs). This causes the system to stay at the current safe height/pressure combination. You’ll Need pressure readings from Techstream software to prove or disprove this.
 
Joined
Mar 31, 2019
Messages
13
Location
Malaysia
So we can start to help and just to be clear about your situation -- please confirm that you replaced all four 'globes' (also called 'Gas Chambers') about one year ago? The 'globe' is the large black item in the first picture -- mounted on the chassis rail near each wheel, so four altogether. The front 'globes' are slightly smaller Also, was the AHC fluid replaced with genuine Toyota AHC Fluid at the same time as the 'globes' were replaced? Is the level and colour of the fluid in the AHC Tank similar to the second picture? Can you please confirm that no other kind of fluid was used in the AHC system?

In addition, can you please advise the year of manufacture of your Landcruiser? This will be found on a label -- either in the engine bay or on the pillar between the front door and the rear door. Left Hand Drive or Right Hand Drive? How is the condition of the vehicle underneath? Does it have much rust?

Also, do you have Techstream? It will be needed for diagnosis. See details at this link:



View attachment 2450003

View attachment 2450005
Ok thanks for the advice. I ll checked through on this weekend and feedback in here again. Is the OBD2 bluetooth dongle can be use for the tech stream?
 
Joined
Mar 31, 2019
Messages
13
Location
Malaysia
Can’t do a proper graduation test without being able to go into high. Most common culprit is hydraulic pressures are too high in the system to safely raise into high (where AHC pressures are the highest and the least weight is on the torsion bars/springs). This causes the system to stay at the current safe height/pressure combination. You’ll Need pressure readings from Techstream software to prove or disprove this.
ok. i ll try for Techstream to retrieve of data. Any mobile apps can be used instead of Tech Stream?
 

LndXrsr

AHC Aficionado
SILVER Star
Joined
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Messages
279
Location
Cincinnati
ok. i ll try for Techstream to retrieve of data. Any mobile apps can be used instead of Tech Stream?

Yes, I think iCarsoft, OBDLink, and VGate work. Others may as well, but try to confirm with others here on the forum.
 
Joined
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Messages
249
Location
Brisbane, Australia
ok. i ll try for Techstream to retrieve of data. Any mobile apps can be used instead of Tech Stream?

The devices mentioned by @LndXrsr are good.

I use the dongle and the app described at the following link on a tablet or a phone. The particular app is important -- costs about USD5 from Google Play. This app seems to work with other dongles as well. Some other apps do not provide AHC information.


NOTE: This arrangement mentioned at this link is good for AHC information but not as good as Techstream for many other things -- so the recommendations to use Techstream should be your priority.

Could you please provide the information requested in post #4 above? In addition, can you please advise whether the vehicle is heavily loaded with accessories or other contents?
 
Joined
Mar 31, 2019
Messages
13
Location
Malaysia
Hi, i upload some of my pictures here for your comment and advice. when i press the UP button, the LED blind for twice then goes off. Nothing happened. No problems to go from N to Lo and vice versa.

1, Fluid level when positioned at Neutral
1601880483534.png


2, Fluid level when positioned at LO

1601880676786.png


3. Colur and condition of fluid

1601880765351.png


4. Front driver side - height sensor. New drive shaft just replaced

1601880900039.png


1601880480893.png
 
Joined
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Messages
13
Location
Malaysia
Passenger side height sensor

1601881425968.png


Empty loaded. No heavy accessory

1601881587161.png


Driver side globe

1601881697719.png


1601881808196.png


1601881246900.png
 
Joined
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Messages
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Location
Brisbane, Australia

Thank you @hiikk in Malaysia. From your pictures it can be seen that your vehicle is a Right Hand Drive Toyota Landcruiser Cygnus. It is not clear whether it has a V8 gasoline engine (2UZ-FE) or whether it has a 6-cylinder turbodiesel (1HD-FTE). The engine details do not affect the AHC situation but there may be some effect on how to set up Techstream or other scanner.

The underside of the vehicle appears to be in good condition. Very little rust is visible.

All four ‘globes’ are from Toyota/Lexus. Your previous message indicated that all ‘globes’ were replaced about one year ago. May we assume that the AHC fluid was replaced at the same time?

By the way, it is important to use only genuine Toyota/Lexus AHC Fluid (Part No. 08886-01805 in 2.5 litre drum or Part No. 08886-81221 in 1 litre plastic bottle) in the AHC system. Other fluids can cause major problems and damage to internal parts of the AHC system.

The AHC fluid looks dark in your tank but maybe that is just the effect of the light in the photograph. The colour of new AHC fluid would look pink as shown in my earlier reply. If there is any doubt the age and condition of the AHC Fluid, then it is best to replace it. The fluid deteriorates with age and old fluid can be the cause of uncomfortable ride.

The front Left and front Right Height Control Sensors appear to be intact but the condition of the single rear Height Control Sensor is not visible and is unknown. However, the only way to know the condition of these Sensors is to remove them and inspect and test them electrically as described in the Factory Service Manual (FSM) and on IH8MUD. Malfunctioning Sensors can cause AHC problems. We can come back to Sensor problems later if necessary.

There are several different kinds of fault conditions which can cause the Electronic Control Unit (ECU) to put the AHC system into ‘fail-safe’ mode. This protects the AHC system and the vehicle from damage.

As @LndXrsr mentioned previously, a common cause of this situation is when the AHC pressures are too high in the front or the rear parts of the AHC system. In such a case, the ECU can prevent the AHC from raising to “HI” because that requires even higher AHC pressures.

Your description explains that there are no heavy loads in the vehicle or on the vehicle, so overloading does not appear to be the cause. By the way, if the vehicle is overloaded, it will refuse to raise to “HI” and may drop to “LO”.

It now is important to use Techstream or other scanner to check the front and rear AHC hydraulic pressures.

These pressures must be in the specification ranges set out in the Factory Service Manual (FSM). These details can be found at https://lc100e.github.io/manual/ . At the Index in the left hand panel, follow the tabs starting at Repair Manual > SUSPENSION AND AXLE > ACTIVE HEIGHT CONTROL SYSTEM > ON-VEHICLE INSPECTION. This section sets out the required front and rear AHC pressure ranges.

The front pressures can be adjusted using the torsion bar adjusters underneath the vehicle. The bolts are turned clockwise to increase the load carried by the torsion bars. This has the effect of reducing the front AHC pressures. High rear AHC pressure is more difficult to correct as changes to rear springs or the addition of ‘spacers’ is required.

The recommended first step for your vehicle is to measure the front and rear AHC pressures. If these are too high, they should be corrected. If the pressures are in the correct range, then it is time to look for other causes.

You also may find it helpful to read about how the AHC system works. A general description can be found at https://lc100e.github.io/manual/ (Follow the index tabs starting at the top:
New Car Features > CHASSIS > Suspension > Active Height Control Suspension).

Please advise if you have been able to check the AHC pressures? If possible, can you please post a screenshot of the readings?
 
Joined
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Messages
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Malaysia
Hi all, i have done the checking using my existing Bluetooth obd adapter and bought some Apps from the PlayStore but failed to read the pressure reading. But it did give one DTC error code C1777.

Screenshot_20201023_213321_com.motordata.obd.jpg


Screenshot_20201023_212846_com.motordata.obd.jpg
 

uHu

Bridgeburner
Joined
Nov 27, 2005
Messages
2,062
Location
Oslo, Norway
The method of reading codes depends on which version of the 100 you have, and which market it was made for. Generally, only US versions are fully OBD2 compliant. Diesel version generally are only M-OBD, no OBD2 at all, although you can get some codes. Then it changed over the years in some markets, like in OZ iirc.

Of the 2 interfaces shown above, the first looks like a specific VAG version (Volkswagen, Audi), and the second one is OBD2. If your car needs M-OBD, OBD2 will not do, as M-OBD is not an OBD2 version.

You could get more specific help by informing of which 100 series you have, i.e. production month, engine, version and market. It's good to make a signature line with this info in it, so that it's easy to relate your info in the posts with the specifics of each version/year/etc.
 
Joined
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Messages
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Location
Malaysia
Hi, my vehicle is import from japan. Year 2004 4.7 v8
Refer picture attached below. Pls advise.

IMG_20201022_163253.jpg
 
Joined
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Messages
249
Location
Brisbane, Australia
Hi, my vehicle is import from japan. Year 2004 4.7 v8
Refer picture attached below. Pls advise.

View attachment 2478224

My recommendations are still the same as mentioned previously in this thread -- Post #4 (“How to: Techstream in 5 minutes”), and, Post #9 (the dongle and app which I use for AHC). I know nothing about the alternatives you have mentioned. There are many devices which have very limited capability and either do not give access to the AHC Electronic Control Unit or are difficult to set up.

As @uHu mentioned already in Post #17, Toyota used different diagnostic interfaces in different markets around the world. As your 2004 Toyota Landcruiser Cygnus has the 2UZ-FE gasoline (petrol) V8 engine, it is possible that your vehicle is OBD2-compliant. There may be a sticker or label somewhere in the engine compartment which indicates this. Alternatively, I suggest show your picture of the Toyota Manufacturer’s Plate at the Parts Department or Service Department of a Toyota Dealer or call the Toyota Head Office in Malaysia and ask them to tell you whether your vehicle is OBD2-compliant, or, what other diagnostic interface was used. The Dealer or Toyota should be able to find the details on the Toyota database if you give them the information.

In any case, suggest try the cable suggested by @suprarx7nut in Post #16 and use the guidance in the “How to: Techstream in 5 minutes” thread, or, use the dongle and app I suggested in Post #9. These both provide an inexpensive way forward. @LndXrsr also made some good suggestions in Post #8.

It will be difficult to make any progress on your vehicle until you can check the AHC front and rear pressures as a first step. So may I suggest just make a choice and see what works.
 
Last edited:
Joined
Mar 31, 2019
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Thank you all for the advise. I have ordered the vci cable and waiting it to be delivered then i ll carried out the techstream of the ahc pressure diagnose.

While waiting for that, i have changed the ahc fluid with toyota original fluid. 2.5 liter of fluid was used. May i know what is correct fluid level at Neutral position?
After i change i changed the fluid, it still not able to go to High mode.

I adjusted the height sensor to highest points, and i can noticed the changes to vehicle height. Which i assume nothing wrong with the height sensor.

IMG_20201029_170445.jpg


IMG_20201029_181238.jpg


IMG-20201027-WA0025.jpeg
 

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