2003 120 Prado air Supension problem

[Dazz Junior Member Find all posts View Profile Close Dazz]

Background:
Air bag failure.
Symptoms:
1/ Height control wokring only intermittently.
2/ Rear starts bouncing around all over the place.

Checks: checked suspension , replaced shock absorbers (Non TEMS type), checked fuse's, relays, connections, switchs in console, plug connections in and under vehicle.
Only fault found was the RH air bag deteriorated and loosing air. (No diagnostic performed).

Action- replaced air bags/ checked air lines from tank to air bags, manually filled and driven for 200+ klms- no leaks.
Continuing symptoms- Heigh control working only intermittently and shuts down- Not filling air bags.
Checked system again- can not find any leaks/ checked all connections again- no apparent issues.

Sent Prado to mechanic to diagnose. Report as follows:
Faults:
DTC
C1727Damping Force control Actuator RR Circuit
C1728 Dampining Force Control Actuator RL Circuit
C1733 Height control colenoid RG Circuit malfunction
C1734 HEIGHT control Colenoid RL Circuit Malfunction
C1735 Exhaust Solenoid
C1741 Compressor Relay Coil Malfunction
C1744 Low pressure Tank Solenoid
C1751Continuious Current to Compressor Motor
C1761 AHC ECU Malfunction

They ran a clear codes and then drove and rescanned the system.
the only faults were as follows:
C1727 Damping Force Control Actuator RR Circuit
C1728 Damping force control actuator RL Circuit

He advised me to re-install the TEMS original shockies to overcome the remaining faults- (And possibly fix the system??)

I replaced/ re-installed my original shocks.
Outcome- no suprise..... No change . Air suspension still not working.
Compressor ran for app. 2mins- but did not effect height or fill airbags/ height control switch worked (Changed dash indicator light) which compressor ran/ but then stopped and whole system frozen.

PLEASE can anyone recommend a fix for this? - my alternative option is to bypass the system and introduce a manual valve system/ or to go to Coils.
by looking at the fault codes am I correct in thinking that it is not a solenoid, or compressor etc- as the faults logged are system wide ( meaning all are reporting fault) and for the reality that all have mechanically failed is simply not probably.

[Dazz Junior Member Find all posts View Profile Close Dazz]

I'm wondering if the system is working against itself?
Has anyone fitted airbags themselves and had to "prime" the system?
- seems like gone are the days for DIY... just take it to the shop.....

[Guest Close Guest]

I have deflated the factory airbags a few times to install airbag spacers. I have removed the factory airbag once to repair the leak in the RH airbag and reinstalled it. I have replaced both factory airbags with Airbagman airbags. All this while, the compressor fired up and filled the airbags up once the rear axle was lifted while the chassis was still resting on axle stands.

[Clackers Junior Member Find all posts View Profile Close Clackers]

Has the Air Suspension ECU been submerged at all? I would try another ECU and work from there.

[Guest Close Guest]

Might also want to check the Suspension off switch operation. Or check for broken wires from that switch or a short. What's the history of the car? Have you had it since new?

[Dazz Junior Member Find all posts View Profile Close Dazz]

Thanks for the replies.
Have had the vehicle from new- never submerged- mostly driven over the years by my untill recently as I started using it again. it's history has been excellent- never had an issue- always been serviced on time.
Has only done a Fraser Island trip once- as most of our 4wd has been in my vehicles.
The first time we've ever had an issue is when the rear started to bounce a few months back and I noticed it was not pumping up. Changed the airbags- checked the system for leaks. Has been to mech's and diagnostic report.
I can start the engine anytime now and I can hear the compressor fire up- but the air is not going to the bags, and the compressor switchs off anywhere from 1-2mins. The console height control can be switched up, down while the compressor is running- but this has no effect on getting air to the bags.
To test the airbags and lines I fitted a 3way connector to the air lines (removing from air tank) and filled the bags with my shed compressor. I did a 200klm trip and no loss of air from air bags through the lines back to 3 way (Near air tank).

I will check the height console switch again- previously I have switched this off and on upon start up- it will start and stop the compressor.


amts, what was the procedure of restarting?- you say you had the axle lifted while chassi was resting on stands? Are you saying the rear chassi was jacked up allowing the rea wheels to droop and then start the engine- ? (By way of "releaving some pressure off the airbags for ease of inflation?)

[Dazz Junior Member Find all posts View Profile Close Dazz]

ok- height sensors appear to be working-
Jacked the rear of the vehicle up and left axel drooping (Hanging).
Started engine- no compressor.
slowly let rear of vehicle down and compressor kicked into life. (Stopped lowering and compressor still ran)
However air bags are not filling.
Compressor shut down after app. 2 mins.
Tried again- same result- can turn adjust height with jack and shut compressor on off depending on Height control selection- so this appears to be ok.

Could be a solenoid problem not opening to get air to the bags.... hmmm

[Dazz Junior Member Find all posts View Profile Close Dazz]

Success

Finally have the suspension working after some 6 weeks "parked-up".
In short heres what I did this day:
*started engine- ran , compressor started but no change to height and air bags not filled.
*removed compressor and remote pawered and chaecked- compressor ran but not producing suffieient air (supply side).
*removed water trap (which sits abovethe compressor- black plastic cylinder) Removed it's lid and found the filters to be blocked and a damp feeling. Inside is on both ends are filters and between these are a spring. surrounding the spring (Trapped between the filters appears to be "hydrogel /) moisture beads which spilt out onto the floor.
* I replaced the filters with some face mask filters, cut to size and through away the hydrogels. The spring was rusty so I figured they were past use by date -also the filters were damp, some rust marks- so I figured this could be the issue!.
* I cleaned the water trap cannister up and put it back together using some Air tool oil to lube things up.
*Put everthing back in the vehicle and started up- still no fix.
*I decided to remove the intake hose from the compressor and found there was some "blowback".. the air seemed to be going the wrong way!
*I removed the solenoid on the feed side of the compressor and it checked out ok.
-
After some furious scratching of the head,.. I figured everything was working but air was simply not been blown the correct way!

I then decided if it's not been blown the right way then I should help it blow the right way- I disconnected the feed line hose before the compressor , which has some simple "spring clip" clamps retaining it- (When it was removed you could feel air blowing out by holding your thumb over the end.
So I started the engine- once again the compressor fired up,.. while this was happening I shoved the air gun down the hole of the Intake line... suddenly there was a couple of distinc sound changes.. I removed the nozzel and felt the air hose-- to my amazement it was NOW SUCKING!!! Yippeee..
I stuffed the air gun nozzell in again and removed it- Yes success the compressor was finally now sucking air from the intake line and not exhausting it!

I have checked the height control u, down, all works.
took it for a drive and everything is how it should be!.

So... after all that what was the problem (Other than the original air bag leak)....

Not sure... will have to Ponder on this one with a few Brewskis...
I'm thinking a valve/ solenoid was simply stuck in the wrong position and no amount of scan tool diagnostic, change this or that was going to fix it.

Thanks to all for comments and interest. I have taken some pics along the way so I may post them in a summary post if it helps others.
The final tally of costs-
I got airbagit air bags delivered from the USA for $450aud. I paid $130 to the mechanic for the diagnostic. all up $580 fix.
Don't even start to discuss my time......

[craigm Addicted PP Member Find all posts View Profile Close craigm]

Well done Daz! And Toyota would have told you it's stuffed and requires a replacement and I'd hate to think what a new one would've cost...


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[Clackers Junior Member Find all posts View Profile Close Clackers]

Congrats Dazz, Thanks for sharing all your info! Might have to check my water trap soon

[Snobbig Lurker Find all posts View Profile Close Snobbig]

Hi Dazz,

Thanks for sharing that, have been scratching my head on this one as it all seems so intermitent. However it sounds as if i need to give this one a go. Do you have those pics you took along the way ? as they may help a fella like me.

Thanks
William

[Dazz Junior Member Find all posts View Profile Close Dazz]

Thanks, will upload pics in a soon.. just gotta sort them out and download some from phone....
Took the Prado for a big tour on the weekend- no problems, beautiful ride... smile ear to ear... kids aren't happy as they have lost their travelling bouncy castle!

[Snobbig Lurker Find all posts View Profile Close Snobbig]

LOL, Many thanks man, look forward to the pic's and real happy for you that your suspension is sorted out.

[ywork Member Find all posts View Profile Close ywork]

Hi Dazz,
Thanks for the information. I have a similar issue where the rear keeps sagging and the pump keeps having to run to keep the airbags up.Im sure I have a leaking airbag. How did you test the airbag to see if it’s leaking?
Cheers,

[Dazz Junior Member Find all posts View Profile Close Dazz]

Heres the pics:
Showing the "air line connection"

I simply used a pair of tweezers inserted and open the small "cams" and the line comes out!

Next to remove the "slide clip" which retains the airbag itself- I used a pair of ling nose pliars from under the wheel arch and pulled it backwards (Towards the rea of the vehicle)

My airbag has perished from age see image; this was where the air leak was found;

I purchased the new airbags from USA- AIRBAGIT and theres is exactly the same as OEM except the airline attachement has a better "quick couple" as shown here:

Not only that I got them shipped to Australia for $450. half the price of local supply and NO Alteration needed!