Air suspension wont vent

[Bulletman]

Gday All,
As the title says the suspension wont vent , fitted new pads, dissicant and checked the compressor exhaust valve which I assume is the little rubber thing with the spring under the nut on the compressor, the 6 or so little holes seem clear.
The car compressor just continues to run then it goes into extended mode or it thinks it is.
Definitely no vent or fart when you stop the car.
Any suggestions on where to look next .
Cheers Bulletman

[Graeme]

Look into why the compressor continues to run as the system certainly won't vent if the compressor is running.

[BradC]

Have you picked up an IID yet? You can watch what it all does in real time which will point to exactly what is going on.

[Bulletman]

The iid tool should arrive next week, the compressor keeps running because the car doesnt seem to know what height it should be in,it thinks it's on an obstacle then tries to raise, then I get the message that once clear of the obstruction reset suspension.
It seems related to the rear as i reckon the rear is continue to raise higher than the front . Hawkeye tells me RR has a totally different offset to the rest of the car but that has been like it before this issue. I removed the exhaust pipe from the compressor and when i drop to access height it vents no problem, but upon start up the car should vent then set its height , well that doesnt happen , the compressor starts and continues to run.
I'm not getting ride height faults, just the fail to vent fault. I actually dont think it's a compressor fault but I will change it just to see as I have a spare. I'm thinking it's a height sensor issue or maybe just a suspension reset as a start.
Cheers Bulletman

[Bulletman]

So I just started the car and dropped it to access height then got out and watched what happened, the car dropped then the rear started to pump up and the front stayed down , hence this keeps the compressor running, then I put it into normal height and it gives a warning on dash suspension raising slowly even tho the rear is close to normal height the front remains low.
Something is causing the rear to pump up so whether I have a blockage and it cant vent the rear or the rear valve block has an issue I am not sure

Cheers Bulletman

[BradC]

When you get the IID, on top of being able to watch it do its thing, you'll be able to manually activate each valve so you can test each element.
Without being able to read the complete fault codes and watch the variables you're kinda flying blind.

If the front is all the way down, and the back is all the way up it'll look like my brothers Prado after the GVM upgrade. At least you won't be flashing other drivers.

[Bulletman]

I can lock the suspension in access height the car will go down and then the rear will pump up for whatever reason even tho its supposed to be locked in access height.
The fact that the car doest vent makes me think it's related. I can get the car to what looks like normal height and pull the relay to stop the compressor so the car is drivable but it's not right. A new relay doesnt change things .
Cheers Bulletman

[BradC]

The first thing it does on fire up is try and adjust the height if required. It then closes front and rear valves and continues to run until the reservoir hits its setpoint. So if the rear valve block was jammed open, then it would continue to run while pushing the back of the car up. The compressor would stop on overheat prior to it reaching setpoint.

If it was stuck open, then the car would attempt to lower and it should lower to the correct height. It'll then try to top up the reservoir which will then push the back of the car all the way up.

Looking at the inside of the valves, I'd be surprised if they both jammed open. The easy way to test would be to put axle stands under the chassis and pull off one of the gallery lines from the center valve block (either front, back or compressor). If the rear valve is stuck it'll dump the back of the car on its arse as all the pressure will dump.

Thinking about it, easiest would be the high pressure line on the compressor that runs to the center valve block.

[Graeme]

It sounds as though a rear height sensor is faulty, indicating that the corner is too low. In the absence of diagnostic equipment I would unplug the RR sensor connector expecting the system to use the remaining 3 height sensors, which it will do but without making fine adjustments.

[Bulletman]

It sounds as though a rear height sensor is faulty, indicating that the corner is too low. In the absence of diagnostic equipment I would unplug the RR sensor connector expecting the system to use the remaining 3 height sensors, which it will do but without making fine adjustments.
Thanks Graeme,
I have a full set of new height sensors but was waiting till the gap tool arrived as I thought you needed to reset the suspension which hawkeye cant do. Is it just a case of unplug the sensor or remove it .
Cheers Bulletman

[DiscoJeffster]

Thanks Graeme,
I have a full set of new height sensors but was waiting till the gap tool arrived as I thought you needed to reset the suspension which hawkeye cant do. Is it just a case of unplug the sensor or remove it .
Cheers Bulletman

The new ones will need to be calibrated to get an accurate height, but an uncalibrated working one is better than a faulty one.

[Bulletman]

So today I changed out the RR height sensor and I dont think that was my problem.
The issue seems to be the compressor continually running, I'm not sure what tells it to turn off.
I notice system pressure got to 1750kpa, the compressor stopped at this pressure but I'm pretty sure it stopped due to temp of 107 degrees. The car still doesnt vent unless I force say access height which it doesnt seem to stay in.
I see there is a pressure sensor in the valve block in front of the compressor, I'm wondering if this is faulty and not telling the compressor to stop pumping.
Or have I totally misread how the system works .
Cheers Bulletman

[DiscoJeffster]

So today I changed out the RR height sensor and I dont think that was my problem.
The issue seems to be the compressor continually running, I'm not sure what tells it to turn off.
I notice system pressure got to 1750kpa, the compressor stopped at this pressure but I'm pretty sure it stopped due to temp of 107 degrees. The car still doesnt vent unless I force say access height which it doesnt seem to stay in.
I see there is a pressure sensor in the valve block in front of the compressor, I'm wondering if this is faulty and not telling the compressor to stop pumping.
Or have I totally misread how the system works .
Cheers Bulletman

You have. BradC has a complete rundown on here how the system works, plus how it self tests itself etc. see if you can track it down with a google search of the site use site:aulro.com in your google search.

[BradC]

Compressor Issue? (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/291052-compressor-issue-post3147254.html#post3147254)

If you have the early Hitachi suspension software it won't vent. This was modified with a software update to vent the gallery to prevent the compressor having to start into a significant head pressure.

If that's the case, you'll be able to update that when you get the IID.

According to the manual, if just filling the reservoir it won't stop unless the head temp > 140C or the brush temp > 130C.

Edit : and this one D3 EAS C1130-66 fault (https://www.aulro.com/afvb/l319-discovery-3-and-4-a/287454-d3-eas-c1130-66-fault-post3107860.html#post3107860)

[Bulletman]

My car used to vent and you could hear it adjusting the suspension every time I turned it off, now I dont get that at all. Even when I jacked it up to remove the wheel to change the height sensor, the car didn't adjust to the car being jacked, normally when I dropped the jack I would have to start the car for it to raise off the jack , didnt need to do that today with the old sensor and the new sensor.
Maybe I'm looking at it the wrong way but the fact it's not venting seems to be somehow related in my eyes.
Cheers Bulletman

[Eric SDV6SE]

My car used to vent and you could hear it adjusting the suspension every time I turned it off, now I dont get that at all. Even when I jacked it up to remove the wheel to change the height sensor, the car didn't adjust to the car being jacked, normally when I dropped the jack I would have to start the car for it to raise off the jack , didnt need to do that today with the old sensor and the new sensor.
Maybe I'm looking at it the wrong way but the fact it's not venting seems to be somehow related in my eyes.
Cheers Bulletman
I know mines a D4 but I'm sure they run the same Hitachi. Mine always vents after self levelling or after parking. I reckon you're on the right track with a dodgy pressure sensor. Comp shouldn't trip on overtemp all the time.

[Bulletman]

Well typically like all things LR , I go away for 2 days with work, come back and start to get ready to attack the air suspension trying to work out why it won’t vent, move the car to a more friendly position for laying on the ground, get out close the door and bugger me the bloody thing vents and self levels….

Oh well saved me some more grief from the Toyota faithful in the caravan park seeing me with the air compressor out again and me under the car….

I can only think it had a blockage, most likely from old broken down disicant and the constant install and removal freed it up… well that’s what I’m telling myself anyway..

A thank you to BradC for taking the time to email some helpful info he has on how the system works.

Cheers Bulletman