Thread: Emergency air up instructions

Originally Posted by loanrangie

F26 is the self levelling fuse in the engine bay fusebox, i assume its the same for L320.

There is also F35 for the EAS behind the glovebox, which I suspect feeds the EAS controller located beside the accelerator pedal.

Yeah, thats the one for the suspension ECU, Im driving around with just it removed currently, I figure there is no point taking out the pump fuse or relay too, as the pump/relay cannot be activated by the ecu if it's had its fuse/power disconnected.

I already have a joiner between the pump and the valve block from the last time i had pump/leaking problems, so this is the first place ill try pumping from, and it means you dont have to deflate the reservoir.

Im thinking im best to disconnect the reservoir valve electric plug, as this is opened when you adjust the height, so if you have the backup pump connected and running while you trigger the height adjustment, to manually set the height, if the reservoir valve is allowed to open (and the tank has less air pressure than needed) you will be trying to pump up your bags and reservoir at the same time which would slow things down considerably.

Alternatively one might want to tap into the tank line , between tank and tank valve, and then just pump the reservoir up first, and then just let the auto levelling do its thing, and manually adjust with GAP if needed. This way you have spare air on hand in the tank if needed.

Originally Posted by RANDLOVER

There is also F35 for the EAS behind the glovebox, which I suspect feeds the EAS controller located beside the accelerator pedal.

F35 is just an 5amp ignition sense wire, so it knows when the car is on, similar too F3 5amp, which is a sense wire for the compressor voltage supply ,

F22 20amp is the main eas ecu power supply

maybe you could just pull the f35 and the ecu will still be running but forced into thinking the car is always off, i might try that and see if the GAP tool can still talk to it or not

that being said the car does level and adjust when the engine is off, so its not really ideal if you want to completely disable auto adjustments

Big update time, made it 450km today towards home (mid nsw coast).

Once the van was on the back, i used the test valves function to put as much air into the rear as possible. At the start i had 135psi in the tank, and by the time it was equalised and no more would go in it was at about 115psi. There was still a bit of a dip in the back, but definitely could have driven it, no worse than some of the vehicles you see towing.

Then I jacked up the jockey jack, lifting the rear of the car up really high, and used the same function to let more air in, once no more would flow, I let it down and the rear was perfect, so very happy I didnt have to climb under and work on anything ! (My ball weight is appx 250kg) The nose was a little high, now, so i let some air out of the front bags. If only id pulled the right fuse the moment i had the pump error, my tank would have 200psi to spend.

We then drove the 70km unsealed road out of the national park and to the highway. But we found that when around 50kmh it would constantly (every minute or so) beep & come up with red error says, suspension fault , max 50km, i could still drive faster but the flashing & beeping error between yellow and red were very frustrating.

Thats when I thought to try the fuse behind the glove box.

Originally Posted by RANDLOVER

There is also F35 for the EAS behind the glovebox, which I suspect feeds the EAS controller located beside the accelerator pedal.

Thank you for pointing this out ! You were right and I assumed the wording in the schematic wrong. The 5amp behind the glove box is the supply to the eas ecu, i found this out after noticing i could read the height sensor with the GAP with the F22 under the bonnet pulled out. The F22 one seems to just be for the valves.

For me though in a 2010 (facelift) L320 the glove box fuse is F10 (and likely D4 too) as my 2009 workshop manual says F35, but the car says F10. Once this was pulled there was no errors at all, nothing, it was beautiful, but a little surprising, that if for some reason that fuse blew, you would have no indication the whole eas system was not working apart from the height adjust buttons not being lit up.

My front was a little tilted side to side according to the height sensors, so i tried to activate the cross flow valve in the front, but that part of GAP musnt work. I suspect i could make individual changes to each bag (instead of in pairs) by using the manual height calibration menu, making sure to re-run that process once all fixed up.

On the drive I started thinking about how i could test pumping the reservoir back , though hopefully I wont need it. When stopped for the day I had another look under the car, the line from the tank to the valve block looks a little thicker than the other lines (which are 6mm) that i have the connectors too, and im hesitant to put a join in this pipe, for if there is even just a small leak, the tank might drain every night and overwork the pump and delay balancing each morning. I think ill look at the threaded inlet on the tank when home, to see if it would be possible to add a T section there and a schraeder valve.

So I thought there's 2 ways I can fill from my join in the pump to valve block hose, one would be to have the pump hooked up to it and start the car, and the car should open the tank valve for the normal pump to fill itself up, but id have the power disconnected to the normal pump (at the pump) so the car is no wiser that instead of the normal pump running its the backup. I would want to have the door open though so that the car didnt try and level itself.

The 2nd option that I went for was to use the deflate reservoir option in GAP, as all deflation happen back through the pump, so instead of deflate it will inflate as the pressure is greater at the pump than the tank.
This went pretty well, I started at 80psi and in about 6-10 minutes I had it up to 130psi. The deflate option keeps the valve open for 2 minutes at a time, so you have to monitor it and activate it again, being extremely careful not to press the buttons next to it which is deflate corners or all, as that would be tragic..... I will try the first 'engine on' option next time im testing, as it also means it could be done without GAP.
Then bang/crack whiz, at the ryobi pump destroyed itself

At least I registered it for warranty, and it will be a instant swap at any bunnings, but sadly this means this pump (while rated to 160psi (10 L/Min @35 PSI)) wont be suitable for this job. So next ill try a 4wd 150psi ~180 lpm pump when i can get one in the next big town.

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Another 300km done today without any adjustments or extra air needed.

At the start of the day I momentarily put the ecu fuse back in to check the levels and the front was down a bit, turns out the heat from the engine causes a noticeable difference in the front air spring pressure that is normally corrected by the system. I had had this happen without realising why on the first day, as id found after starting level when cold and driving for an hour the front had popped up, so id had to manually let it back down level.

Arriving in the the caravan park, we are stopping for 2 days, so took the van off and the back popped way up and the nose down a little. Letting down the rear was simple enough, except my filling valve now blocks deflations which would normally go back to the pump, so i had to remove that connector first. I put it back on and tried to raise the front , but it went down instead ! I must have had less air in the tank than needed.

I drove and picked up the new pump I ordered click and collect for $200 ($100 off), and this thing is a beast. It can fill the tank to (the pumps) max pressure 150 psi in about 2 minutes from empty and comes with anderson plug (as well as standard battery clips)

The thing that really surprised me was just how much more pressure the front needed than the back ! The rear would be level at around 100 psi, while the front took every bit of the 150psi the pump could do. (TDV8 being heavier)

I did a bunch of other investigations too now that i had ample air supply:

- Turns out the ecu detects if the motor it unplugged too ! So that means there is no way really to fill the tank via the standard engine start method and not need a GAP, unless you plugged your backup pump into the cars pump power supply plug.

- As mentioned by using a single connector on the pump line (not t) there is no way for the system to lower or deflate, so if you need to you can take the valve out, or i later worked out its easier to press the valve center first to release pressure, then simply take quick-fit connector of the pipe instead.

- I tried a "T" into the pump line so that i could keep the factory level/balance mechanisms while driving, and it could even be left in permanently, problem with this is that when filling the tank via the deflate GAP option, you need to unplug the pumps multi plug otherwise it will actually deflate your tank, and then plug back in once full. I decided i did not like this approach, as the system will eventually waste your air supply, each time you start up the car or hop in/out, and you have to look at the errors. I decided id rather go full manual and just run with the ecu or valve fuse unplugged once pumped up and level so nothing changes. Also there could be pump failure scenarios were the pump piston or dryer housing cracks and doesnt hold air and has to be disconnected to get the system air tight again.

- I found while driving around town without the van with the ecu on, but valve fuse pulled id only get the single yellow suspension error, so there must be something about having the van on that triggers the more persistent red errors. Maybe the extra bumping around.

- I found you could use the 'test valves' function with the pump connected it would keep the valve open as long as you held the button, so with the digital display pump i could have it idle and push the up arrow in the app for say the rear and if the tank and pump where equal i would see the pressure of the bag/tank on the pump screen, and then, while still holding, i could start the pump and it would pump up the selected springs and the tank at the same time, and in the case of the front springs where i needed as much pressure as the pump could supply, but the time the springs would not raise any more and the pump had stopped at it target/max pressure the tank would be full. So this is a way to fill the tank without the deflate method, so long as the max tank target is the same as the front or rear spring. One could even unplug the tank control valve wires if there was a leak in the tank or its pipe, and pump the bags alone.

- If you accidentally start a deflate, or jut want to end one early, just turn the car ignition off and on, it will stop, and the app will say 'deflate failed' but still keep working fine without a reconnect.



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The EAS is very sensitive, I've often had my rears deflate a bit in the garage with the roller door open early morning as the sun heats and expands the airbags.

One issue that may crop up is the amount of moisture your tyre pump will have pushed into the system. Last time I went away I added a moisture trap to my compressor when airing up after a few off road excursions and the amount of water it caught was surprising.

Suppose it depends on the humidity in the area you are in, but I now see the reason for the bloody big desiccant chamber.

Anyone who has done a lot of 4wding knows how much water gets pumped out of a compressor every time they air up
there is no way I would pump that into my suspension