AHC suspension replacement (1 Viewer)

[AtinLango]

I have LC Amazon 2002 (Diesel). i have driven since 2018, and it is in very good condition. Have had no major issues other than maintenance.

Recently replaced "shocks absorbers" and all four globes since it was driving harshly. Since 2018, graduation test slowly reduced from around ten to around five as of the time of replacement recently. After replacement, the car is now driving so smoothly, but graduation test has remained at five, which is bothering me.

Any advice on whether I should worry about the graduations or not.

 

[AtinLango]

I have LC Amazon 2002 (Diesel). i have driven since 2018, and it is in very good condition. Have had no major issues other than maintenance.

Recently replaced "shocks absorbers" and all four globes since it was driving harshly. Since 2018, graduation test slowly reduced from around ten to around five as of the time of replacement recently. After replacement, the car is now driving so smoothly, but graduation test has remained at five, which is bothering me.

Any advice on whether I should worry about the graduations or not.

Now AHC is stuck in low at the front. Rear can move from L to N and vice versa. I have tried to drive a bit, and also checked that AHC fuse in engine bay and looks ok. But so far it is still stuck.

 

[AtinLango]

Now AHC is stuck in low at the front. Rear can move from L to N and vice versa. I have tried to drive a bit, and also checked that AHC fuse in engine bay and looks ok. But so far it is still stuck.

Apologies, i forgot to say that yesterday my mechanic tried to bleed the system, and found a lot of air in. Its possible more air is still in. It was after the bleeding that today the system got stuck in L at the front

 

[AtinLango]

Apologies, i forgot to say that yesterday my mechanic tried to bleed the system, and found a lot of air in. Its possible more air is still in. It was after the bleeding that today the system got stuck in L at the front

i can hear the motor running when i press AHC button.

 

[Wilsil]

Have you replaced the fluid?

 

[suprarx7nut]

Sounds like there's a blown globe or two or it hasn't been bled properly.

A set of new globes should return 14+ grads.

You should also check neutral pressures and adjust the front torsion bars accordingly. They are almost certainly out of spec. Very easy and free fix once you read the pressures.

 

[AtinLango]

i can hear the motor running when i press AHC button.

Meanwhile, i am planning to buy more flui

Have you replaced the fluid?

Yes, i used two 2.5 liter cans.

 

[Wilsil]

Do you have the Techsteam and reader?
That will give you the pressure of the system.

You are stating that you have recently replaced all globes.
But also since 2018 that the graduation has reduced.
This recently is before 2018?

 

[AtinLango]

Do you have the Techsteam and reader?
That will give you the pressure of the system.

You are stating that you have recently replaced all globes.
But also since 2018 that the graduation has reduced.
This recently is before 2018?

I am borrowing techstream today. Will test and share results.

The recent replacement i am talking about was within the last one week. It was done by a mechanic in my presence because i do not know how to do it.

The mechanic did not bleed initially inspite of my guidance. So two days ago i called him to bleed and he found lots of air. I think more air us still in. Then the system started jamming after that.

The bleeding got out clear fluid with small bubbles. As i stepped out a bit to pick more new fluid, i found the mechanic had reused the bled fluid, claiming that he had first let the air evaporate. I dont know whether this can be an issue.

Previous fluid flushes were done by some other mechanics under my instructions, and they always yielded good results in performance.

Last evening i disconnected both batteries, and reconnected this morning. I thought it woyld possibly reset the system, but it is the same - front stuck in L, and rear able to move between L and N.

 

[Wilsil]

Doesn't look like the mechanic knows what he is doing.
Is he also re-using engine oil after letting the air out? It has already be contimanated, how small it is.
I would definately not going back to him.
My understanding of the system is that it is very simple.
It has the globes/accumulators, 4 "shocks" or rams, a pump and reservoir. Also 3 level sensors, 2 in the front an d1 in the rear.
You have replaced the shocks, globes and fluid with new. Fluid flushing might be questionable by the sound of it though.

Techstream will give you more info regarding the pressures. Read up on how to do it. @PADDO has done a great job to desribe it.

 

[alikhaneng]

You need to check the mechanical issues.

Have you bleed the height control accumulator (the 5th item to bleed)?. Let me put picture here for understanding.

also check if the valves stuck ?

I attached the AHC system schematic which will help you.

 

[AtinLango]

Unfortunately, the other mechanic with techstream has let me down. I waited for over six hours, but everytime i call he would say he would be there in 10 mins. Finally given up on him.

Now pondering on next move. Not sure if it wil make sense to let the first mechanic check the system again. He promised to pass by tomorrow.

 

[AtinLango]

In the meantime, if the front can raise to N, would it be a bad idea to drive like that as i wait to sort it out? Btw, the damping effect was wuite good when height was in N, even just before getting stuck on L yesterday. Currently in L, it is not driveable.

 

[AtinLango]

Now, even the original mechanic who changed the shocks and accumulators is not picking my calls, though yesterday he had promised to pas by. I am giving up on him as well.

I am planning on getting any mechanic around to try to help raise front of the car from L to N. What I know is there is still air in the fluid, but we can may be deal with that after.

Would there be some simple procedure that I can direct the new mechanic to follow to try to raise the front from L to N?

 

[AtinLango]

With no help coming from my mechanics here, I am glad that I joined this forum, to which I owe all the gains. I have read various threads in this forum, and it has really helped me.

Now, I have just been able to raise the car from L to N. Remember I am no mechanic even to the lowest degree, but I read a lot, so that is where the power lies. I also know quite a lot just because of reading.

At least the car looks driveable again, though I am cautious not to drive it yet.

These are the steps I followed, courtesy of this forum. Note that my aim was to disable the front sensors, though it did not work at once.

1. Disconnected both front sensors using the black connectors in the engine bay. I did this when engine was off. After restarting car, the AHC indicator went from L to N, but the car did not raise (no matter how many attempts).

2. Now, I thought of disconnecting only the left or right sensor. So, I re-connected the left sensor and disconnected the right. Same result as 1 above. No success.

3. I reversed the order (disconnected the left, re-connected the right). After restarting the car, it started rising (both front and rear), though slowly. The car now physically appears to be in N (and the indicator is in N). Driving it along my driveway seems smooth. I have activated the AHC OFF button just so that it does not move back to L.

I know I am still far from a solution, as I believe there is air in the fluid. Still pondering next steps. A million thanks to you all in the meantime.

 

[AtinLango]

With no help coming from my mechanics here, I am glad that I joined this forum, to which I owe all the gains. I have read various threads in this forum, and it has really helped me.

Now, I have just been able to raise the car from L to N. Remember I am no mechanic even to the lowest degree, but I read a lot, so that is where the power lies. I also know quite a lot just because of reading.

At least the car looks driveable again, though I am cautious not to drive it yet.

These are the steps I followed, courtesy of this forum. Note that my aim was to disable the front sensors, though it did not work at once.

1. Disconnected both front sensors using the black connectors in the engine bay. I did this when engine was off. After restarting car, the AHC indicator went from L to N, but the car did not raise (no matter how many attempts).

2. Now, I thought of disconnecting only the left or right sensor. So, I re-connected the left sensor and disconnected the right. Same result as 1 above. No success.

3. I reversed the order (disconnected the left, re-connected the right). After restarting the car, it started rising (both front and rear), though slowly. The car now physically appears to be in N (and the indicator is in N). Driving it along my driveway seems smooth. I have activated the AHC OFF button just so that it does not move back to L.

I know I am still far from a solution, as I believe there is air in the fluid. Still pondering next steps. A million thanks to you all in the meantime.

Quick question: having done the above, including activating AHC OFF, can the car fall from N to L by itself while driving. I fear the worst.

 

[AtinLango]

Another question: since i was able to raise the car from L to N by disconnecting the front left height sensor, does that mean that sensor has an issue? Can i open it and see. And probably clean and put back? Am just here on my own.

Secondly, if the issue is the height sensor, was it by coincidence that it happened after a fluid bleed?

 

[AtinLango]

Latest update:

I got someone new to help me bleed the system again.

We bled the Front Left and there was some air, which eventually stopped.

I then remembered that the long accumulator (in the middle) was not bled a few days ago when we bled the system. The original mechanic has actually been reluctant to bleed it right from the beginning, saying it is not necessary. So, we moved on to that. Bleeding pushed out some very little old black fluid (yet we thought the system had completely new fluid throughout). It was so little, meaning that accumulator was basically empty. We stopped there for some other reason.

I managed again to bring the car to N (though physically looking a bit "Lowish"). I have also disconnected switches for all three height sensors (two front and one rear).

The ride is feeling rather spongy, but at least the car can be driven.

Now, I am again on my own here. Any thoughts would be appreciated.

Some direct questions:

1. Should I continue driving in this situation as I wait for a solution?
2. The fact that the fifth accumulator was (and presumably is still) empty, what does it mean? Some blockage, etc?
3. Is my AHC pump likely okay since the car is at least able to move up from L to N when the height sensor switches are disconnected?

Thank you. I appreciate.

 

[AtinLango]

You need to check the mechanical issues.

Have you bleed the height control accumulator (the 5th item to bleed)?. Let me put picture here for understanding.

also check if the valves stuck ?

I attached the AHC system schematic which will help you.

View attachment 3406877

View attachment 3406879

Looking at the schematic, and the fact that we have just found the accumulator virtually empty (save for very little old fluid), I am thinking that the valve could as well be stuck. I have tried to go under the car, but I cannot easily locate the valve. I could just feel a wire ending around the area on the accumulator that has been labelled "solenoid valve".

 

[suprarx7nut]

Latest update:

I got someone new to help me bleed the system again.

We bled the Front Left and there was some air, which eventually stopped.

I then remembered that the long accumulator (in the middle) was not bled a few days ago when we bled the system. The original mechanic has actually been reluctant to bleed it right from the beginning, saying it is not necessary. So, we moved on to that. Bleeding pushed out some very little old black fluid (yet we thought the system had completely new fluid throughout). It was so little, meaning that accumulator was basically empty. We stopped there for some other reason.

I managed again to bring the car to N (though physically looking a bit "Lowish"). I have also disconnected switches for all three height sensors (two front and one rear).

The ride is feeling rather spongy, but at least the car can be driven.

Now, I am again on my own here. Any thoughts would be appreciated.

Some direct questions:

1. Should I continue driving in this situation as I wait for a solution?
2. The fact that the fifth accumulator was (and presumably is still) empty, what does it mean? Some blockage, etc?
3. Is my AHC pump likely okay since the car is at least able to move up from L to N when the height sensor switches are disconnected?

Thank you. I appreciate.

Start with simple.

1. Plug in all the sensors. Leave them all plugged in.
2. It is unlikely that you can open the sensors and assemble them again and fix anything. The sensor internals are very sensitive and the only reliable solution is new Toyota/Lexus sensors.
3. The car might be stuck in L because your torsion bars need adjustment. Crank each bar 5 turns up (clockwise). That should lower your pressures and make the car mroe likely to get to N.
4. You need to read data from the AHC computer. OBD Fusion with an ELM bluetooth OBD bluetooth dongle works. Or a laptop running techstream (available for download free on here). Once you connect you will quickly see what the problem is. Fixing this without reading that data is very, very time consuming and potentially expensive.