Suspension compressor runs constantly

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Dave Marriott

Member
Posts
72
Location
Sheffield
I've been getting the suspension warning light for a week or so on my Disco 3. I pulled fuse F26 then left the car overnight and the front end dropped both sides. I dismantled and cleaned the front valve block. After this the warning light still came on but when I again pulled the fuse and left it overnight nothing dropped at all. Next step was to buy and fit a compressor repair kit consisting of piston seal, and drier components. Car pumped up quickly but after a few minutes light came on again. When cold it takes about five minutes before light comes on, after that when I turn ignition off and on again the light comes on in a few seconds. The compressor runs continuously and i suspect the warning light is coming on because the compressor is overheating.

I'm assuming that there is a leak or a faulty pressure sensor on the compressor. I've read that the exhaust valve can leak but unfortunately the kit didn't have replacement bits for this and I wasn't aware of this when I overhauled the compressor so didn't touch that part of it.

Does anyone have any ideas how to diagnose the problem? I was thinking of buying a i930 diagnostic tool does anyone know if this will diagnose this type of issue?

Thanks
 
Why did you remove F26 cos it has nothing to do with SLS, if you misstyped it and was F28 dont mess with it anymore cos it's for the SLABS ECU and you mix up the internal counter , remove relay R5 or FL9 to stop the compressor cos it's possible that it can't pump enough to reach the target heights or there's a leak somewhere or the system is decalibrated... first of all rule out a sticking relay by putting a new one or R3(headlamp wash) instead of R5.... to correctly diagnose that you need a dedicated tester which IMO is "smarter" than that ICarsoft ...eventually insist with it's builder to confirm it has D2 SLS calibration, DTC and live data capabilities.

you can make a trick to see if the calibration is good as to start jacking it up from the towbar while the compressor is running and see if it stops or not(only after you ruled out the relay...though if it's the relay and it was replaced the system will start acting normally)
 
Thanks for the reply Sierrafery, I read on the Internet that F26 disabled the ECU that does the auto-levelling and a good way to test the airbags was to pull it and deactivate the front and rear block valves. Here is link to article https://landroverforums.com/forum/lr3-28/suspension-troubleshooting-66245/
At this stage I hadn't noticed that the compressor was running all the time. One thing I have noticed is that if I select "Off road height! the car goes up fine but the compressor keeps running. If I then select "Normal height" when the car gets to normal height the compressor stops for a second and then starts again.
Thanks again for the help
 
I'm affraid that my reply is not much help when it comes to a D3 cos it's completely different... the only good advice i can give is to read the stored fault code cos it might point you in the right direction... though as long as the vehicle stays on level and the compressor keeps kicking in seems like there's a leak in the air reservoir and can't hold pressure then the compressor is trying to override that or the pressure sensor is making tricks.... find the compressor relay, remove that and see what happens though you'll end up with all kind of fault codes triggered by these tests which will embed the real problem IMO
 
Dave Marriott said:
I've been getting the suspension warning light for a week or so on my Disco 3. I pulled fuse F26 then left the car overnight and the front end dropped both sides. I dismantled and cleaned the front valve block. After this the warning light still came on but when I again pulled the fuse and left it overnight nothing dropped at all. Next step was to buy and fit a compressor repair kit consisting of piston seal, and drier components. Car pumped up quickly but after a few minutes light came on again. When cold it takes about five minutes before light comes on, after that when I turn ignition off and on again the light comes on in a few seconds. The compressor runs continuously and i suspect the warning light is coming on because the compressor is overheating.

I'm assuming that there is a leak or a faulty pressure sensor on the compressor. I've read that the exhaust valve can leak but unfortunately the kit didn't have replacement bits for this and I wasn't aware of this when I overhauled the compressor so didn't touch that part of it.

Does anyone have any ideas how to diagnose the problem? I was thinking of buying a i930 diagnostic tool does anyone know if this will diagnose this type of issue?

Thanks
Click to expand...

hi

as @sierrafery mentions, it sounds like an air leak, more than likely in ur air tank , the compressor keeps running trying to make the air up and causes the compressor to overheat and then gives the warning symbol on ur instrument panel

a code reader is a must with these vehicles, sorry but don’t personally know how good the i930 are , can say , the iid diagnostic reader by gap are extremely good ,

u need to see what the compressor is outputting in the way of pressure , inc the fault codes

the air tank leaks on top at the seam where u can see it , doesn’t take much to remove it, u then lay it on the floor, reconnected to ur compressor , run the engine and bubble the air tank for leaks ,

there are other issues that can cause issues but the air tank is the first to look at and easy to check

plse let us know how u get on

PS , just thought , plse

1) does the compressor stop running in access mode
2) is the symbol on ur display orange or red
 
Hi gstuart, sorry missed the last bit of your message.
Compressor still runs in access mode. When I change from off road to normal it stops for a second when normal height is reached and then starts again. When I go from normal to access mode it again stops when access height is reached then starts again and stays on.
The compressor stops when the yellow light comes on.
When I drive it the light is normally yellow but goes red sometimes
 
Dave Marriott said:
Hi gstuart, sorry missed the last bit of your message.
Compressor still runs in access mode. When I change from off road to normal it stops for a second when normal height is reached and then starts again. When I go from normal to access mode it again stops when access height is reached then starts again and stays on.
The compressor stops when the yellow light comes on.
When I drive it the light is normally yellow but goes red sometimes
Click to expand...

no worries, lol ,

thks ref the replies , like ur self , my concern is u burning ur compressor out

is good that u pulled the F26 fuse overnight and resolved the front dropping

when the light goes red that normally means the compressor is overheating

just using soapy water is fine to test for leaks , if there is a leak on the air tank it’s normally always on that top seam running down the length of it

if u prefer , disconnect the air tank and u can use a foot pump to pump up the air tank and then check for leaks if u don’t wish to use the compressor to pressurise it

plus plse check the wires on ur reservoir valve under the compressor cover whilst checking the air tank
 
Last edited:
Dave Marriott said:
Thanks again, I'll give that a go tomorrow and let you know the results
Click to expand...

no probs and always happy to help where i can , u will find the forum a great bunch

thks, will be good to see what u find

at least as well ur not having to pay the local landy dealer , lol , see they currently charge £120 per hour plus vat, gulp
 
Certainly is a great forum.
£120+ VAT an hour? I'm definitely in the wrong job.
Thanks again for your help.Will let you know what happens when I've checked the reservoir
 
Dave Marriott said:
Next step was to buy and fit a compressor repair kit consisting of piston seal, and drier components. Car pumped up quickly but after a few minutes light came on again.
Thanks
Click to expand...

Can I ask what compressor you have and whose kit you bought please - Was there an appreciable difference in performance (not withstanding the other issues you might have identified now)
 
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