Toyota Prado height control malfunctioning, help required

[azamji]

assalam-o-alaikum to fellow pakwheelers

I have Toyota Prado 2004 TZ G-Selection model which includes height control system. In the past 2 months its height adjustment started malfunctioning. Whenever the car is parked for 2 3 days without starting, the air in its suspension lessens to zero, which previously did not happen irrespective of no. of days it was parked. So when the car is started and taken out it feels quite a bit jerky. If its height is adjusted manually to HIGH mode, its takes more than its 'normal' time to adjust but everything becomes fine eventually.

However on 2 separate occassions, the air in its rear suspension filled so much that it felt just like a cat when its ready on its heels to pounce on its prey.

I showed it to Toyota Walton, Toyota Ravi, Toyota workshop on Jail Road and some other workshops who specialize in SUVs but to no avail. All the toyota workshops were useless, no expertise at all, the only thing they could do was to release the air manually from the rear suspension when it was absurdly high on those 2 occassions.

Has anyone of my brothers here faced a similar problem? can experts suggest me what might the problem be and guide me how and from where to address this issue?

thanx in advance

[hash4u]

since the mechanical part seems to be working fine
using "common sense" i can tell you the sensor controlling the AHC is malfunctioning

[Spano]

^^^
yes, thats the only thing that might be having some problem

[Xulfiqar]

the height level "scale" is malfunctioning; fixed it in a 1992 Crown once, it was also riding high on its heels, I think the scale was located near the front right wheel, and on the rear diff unit connected to the body - The unit was replaced. There was a special toyota tool to check the whole system independantly on pre OBD2 cars, but I think any Big toyota stealership fixing majestas would have the scan tool

[azamji]

@hash4u and spano
thanx guys but the sensor was checked several times and it came out to be working fine. besides whenever the height mode is changed, its works fine

@xulfiqar
thanx, ill try to consult toyota again and ask for this scanning tool, however they did use it if i recall it correctly and no problem was highlighted

[riz_]

There is a leak in one or both of the air springs commonly known suspension airbags. Both air springs are connected through air pipes, so a leak in just one of them would cause the symptoms you have described.

Key diagnostic observations that yo made:

• All the air leaks out when the vehicle is parked.
• It takes longer for the pump to get the vehicle back to normal height.
• The harsh ride, before air is pumped into the air springs.

All of these points to one thing and one thing only; leak in air suspension system. Almost always it is the air springs. But considering road conditions in Pakistan, it is possible that the pipe that pumps the air is damaged.

It is not possible to repair any of these parts. They must be replaced.

[riz_]

To find the leak. you will need a car lift, bucket full of soapy water and a towel. This is how you would check for the leak:

• Start your vehicle and wait till the air suspension levels the vehicle properly.
• Switch off the air suspension system. I don't know where the switch to do that is in your particular vehicle.
• Raise the vehicle on the lift. If the air suspension is not switched off, this system will release the air in the system as soon as you raise the vehicle.
• Soak the towel in soapy water and apply liberal amount on the air springs. Make sure you don't miss any part. You should be looking for a steady stream of bubbles. When you are done with the air springs, do the same with the pipe that leads from these springs to the pump in the engine compartment.

Good luck.

[azamji]

@riz
thanx alot man, ill surely try that one as well in the morning and post the results, i hope the problem gets located

[hash4u]

Riz
nice info!

[azamji]

@riz
janab i checked what you told me, there was no leakage in the air springs or the pipes connected to it.

However, one more info that i got from an old friend today was that he faced similar problems in his land cruiser cygnus 2005 model almost 1.5 yrs back. Interestingly, or rather spookily, according to him this sensor malfunctions only "sometimes", rest of the time it works fine (dont know what that meant). He said he replaced it, costed him rs. 25000 and his car is working fine since.

He took me to a workshop on Ferozepur road from where he got his car fixed, the technician there switched off the sensor permanently after adjusting the car to its correct height, and asked me to use my car for a few days, if the problem is resolved then the sensor is the culprit and we can change it lateron.

[riz_]

@riz
janab i checked what you told me, there was no leakage in the air springs or the pipes connected to it.

Good to know that there is no leak.

... the technician there switched off the sensor permanently after adjusting the car to its correct height, and asked me to use my car for a few days, if the problem is resolved then the sensor is the culprit and we can change it lateron.

Seems like a good plan. Let us know what happens.

[azamji]

i will surely let you know

current status: the car worked fine today, going to leave it for 3 4 days now, this should reduce the list of expected culprits by atleast one

[azamji]

todays status: started the car after 5 days, used it all day long and no problem occurred, which leads us to only one logical conclusion: the damn sensor has become a drunkard and loses its balance occassionally

[Dawar]

Same problem is occuring to my Prado 2003 TZ... rear air suspensions are down to zero and the vehicle is quite jerky...like a donkey ride ! checked by the toyota dealership... they caught leakage in the air filling pipe which fills the air suspension bottles from the motor behind... after repairing the pipes the vehicle went up for a while and then went down...
motor i guess isnt working properly or the sensor.. doesnt know...
just got the air suspension bottles filled manually by the air pressure pipe from the air conditioning mechanic and disconnected the plugs and switches from the motor and suspension... vehicle is fine standing up but the hieght control is not possible...

Any solution... should I keep running the prado like this or it may be harmful .. or should change the sensor or the motor.. tell me how to know about it...

[rhl_yousaf]

Brothers same issue with my Prado too...
Any solution/Or latest date regarding this issue?
Please recommend any workshop...

[hash4u]

My friend bought 100 series.....curious they were playing with height control n after couple of times it got busted
They replaced the hydraulic pump/oil from pindi saddar as far as i recall

[rhl_yousaf]

Thanks brother appreciated it...

[Dawar]

Had pearl white 2003 TZ... Same happened exactly..
Do following steps
1. Unplug battery wires both for 10mins then plug them back.
Check height control and check the next day if its fixed. Its a soft reset- dont worry about auto power windows will be normal after 24hrs. Hopefully malfunction will go.
2. If not then get it computer diagnosed via tab like super computer used for JDMs. Rs.800-1000 to get diagnosed. It tells precisely about malfunction cause electrical or mechinical.. If electrical then from computer he can manually control height control and fix no big deal.
3. Last if mechanical then
There are 3 things
A. Air pump at the rear left under the bumper. Cost 40000-65000.
B. 2 Air bottles under rear each shocks. 20000 each.
C. A pipe which connects air pump to the bottles.

Usually the pipe gets rust and leaked and cause pump to act eratic. If the pump or bottles are faulty they are replaceable but the pipe isnt.
Ask the mechanic to take the air pump motor out just 4 nuts at rear extreme left under the bumper with the pipe..go to a cng wala and ask for cng pressure pipe the size of your faulty pipe. Take that pipe and go to AC mechanic and ask him to fix pipe with the pump and ensure no air leakage. Fit the pump back and you are better off even before.
Dont take tension... It will be fine Hopefully with battery unpluging step.

Sent from my LG-H811 using PW Forums mobile app

[aalatif]

Replace the pneumatic height control device, I had the same issue and was rectified by Toyota Southern in karachi. You can do some checks also, like height should come down to normal even at a H or L when driving. Further, your diagnostics ( connecting diagnostic tool) should also tell you about alarm condition. I hope this helps

[josekoech]

I have a Toyota Prado Tz in Eldoret Kenya and i have encountered a mulfunctioning rear suspension. I took the car to local mechanic who said that the air pump might be affected by dust. He removed the air pump at the rear left under the bumper and cleaned it. After all this the problem was not sorted.

Anyone with clues on where this can be fixed in Kenya?