Can the onboard computer effect the ride comfort

Hi,

I've had my 2004 Range Rover Vogue for a year now. I've noticed the luxury ride comes and goes. There does seem to be a pattern emerging. When the car has been in the garage and plugged into the diagnostic machine the car comes back and rides fantastically - floating on air. After a few days and a few miles this feeling vanishes. The ride becomes bumpy and doesn't feel balanced on corners.

Can anyone shed light on what maybe happening with the car. This problem seems to point to the onboard computer.

Thanks in advance.

Mark

My first guess would be the EAS Compressor is giving up and not providing enough air to the tank and subsequently not enough air to keep it up during self leveling....

Once it has been in the garage, they will most likely run the car for 20 minutes with a door open to allow the compressor to fill the tank, then perform a ride height calibration to ensure it is at the correct settings, then run it with a door open again to refill the tank and give it back to you with a full air tank...then over a couple of days the car self levels a good few times, but the poor compressor can't keep up with it and you car starts riding lower and lower....

Do a search on here for the L322 Ride Height measurements (I will try and repost my height drawings for you) and when it starts getting harsh - measure the ride height and see if it has dropped.

Suspension air bags will start getting old and need replaceing after about 8 years so if yours are originals, they'll be on their last legs by now....causing the compressor to work over time to keep them inflated.

Invest in your own Diagnostic Computer so you can recal the ride heights and clear faults yourself, this will save you a bundle at a dealers....

If the air in the bags is lost or the compressor doesn't pump them up enough surly wouldn't the height sensors notice the height issue and throw a fault ?

Less pressure in the bellows should equal a softer ride.

Thanks for the reply. Very informative. I've just measured the heights and they seem okay - give or take 5 or so mm.

From time to time though the driver's rear arch does seem to sit low. Seems to drop when I lock up the car.

I've also been conscious of a ticking sound from the boot which I guess is the compressor. Sometimes this has carried on for 10 minutes or so from starting up the car.

I have arranged for the guy who has the diagnostic equipment to pop down on Friday. I've mentioned to him that each time he plugs his equipment in the car seems to be great for a few days.

He's mentioned the 22" tyres. However, I've told him I'm happy with the ride with these tyres, what I don't understand is the deterioration in the ride after a few days.

How much is a Diagnostic Computer? Assuming it's easy once you've used it a few times?

scuffian said:

Thanks for the reply. Very informative. I've just measured the heights and they seem okay - give or take 5 or so mm.

From time to time though the driver's rear arch does seem to sit low. Seems to drop when I lock up the car.

I've also been conscious of a ticking sound from the boot which I guess is the compressor. Sometimes this has carried on for 10 minutes or so from starting up the car.

I have arranged for the guy who has the diagnostic equipment to pop down on Friday. I've mentioned to him that each time he plugs his equipment in the car seems to be great for a few days.

He's mentioned the 22" tyres. However, I've told him I'm happy with the ride with these tyres, what I don't understand is the deterioration in the ride after a few days.

How much is a Diagnostic Computer? Assuming it's easy once you've used it a few times?

Click to expand...

If it drops, you almost certainly have an air leak, probably the airspring on the corner that goes down.

The ticking sound in the boot.... Is that with the engine running ? As its probably the fuel pump

Diagnostic Computers:

• Cheap end is the All Comms from RSW Solutions - About £200 and runs on a Laptop, can recal the EAS and read and clear Faults
• Middle of the Road is the IIDTool from Gap Diagnostics - About £250-300 self contained and fairly powerfull by all accounts.
• Middle of the Road is the Bearmach Hawkeye - about £350-375, is self contained but cant recal ride heights.
• High End is the Blackbox Solutions Faultmate Extreme - about £1000 but is the absolute muts nuts...

You may have noticed my thread on air suspension tonight

I have been live data reading all day and I can confirm that if a non-fatal error occurs then the Air Suspension Inactive warning does not come BUT the ride quality goes from Luxury to Harsh

Reset the ecu with my Snap On and Luxury instantly returns

My theory is the Luxury control element of the ecu shuts down to conserve any air in the receiver so the suspension doesn't drop to bump stops quickly which allows the vehicle to still be driven

Does running the engine with the door open always allow the compressor to fill the tank?

Strangely the car doesn't seem to be getting lower.

scuffian said:

Does running the engine with the door open always allow the compressor to fill the tank?

Strangely the car doesn't seem to be getting lower.

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Yes because if the tank level is low and the compressor is running...leaving a door open locks the system from changing heights and as such the compressor is only filling the tank and not trying to level the car....

I'm sorry Guys but I can't understand how there can be a 'luxury' setting within the ecu. To hold the car up there must be a certain pressure within the airbag, this does not change unless the car gets heavier, people get in or the boot is loaded. More pressure is then required to keep the vehicle at the selected height. Surely then if the vehicle is raised to offroad height only the volume of air in the bag changes, more air is required to lift the vehicle and expand the bag, the car hasn't got any heavier just because it is 2 inches higher. If we therefore assume the best ride quality is a lower pressure airbag (more compliant) then driver only with low fuel should be a more luxurious ride than 5 up, full tank and loaded up for a wekend camping. Or have I got it wrong.

Would it be worth running the car for 10 minutes with the door open to see if it makes any difference?

spitfire said:

I'm sorry Guys but I can't understand how there can be a 'luxury' setting within the ecu. To hold the car up there must be a certain pressure within the airbag, this does not change unless the car gets heavier, people get in or the boot is loaded. More pressure is then required to keep the vehicle at the selected height. Surely then if the vehicle is raised to offroad height only the volume of air in the bag changes, more air is required to lift the vehicle and expand the bag, the car hasn't got any heavier just because it is 2 inches higher. If we therefore assume the best ride quality is a lower pressure airbag (more compliant) then driver only with low fuel should be a more luxurious ride than 5 up, full tank and loaded up for a wekend camping. Or have I got it wrong.

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Your not wrong - and the ECU doesn't have a Luxury Mode....you are quite right.

scuffian said:

Would it be worth running the car for 10 minutes with the door open to see if it makes any difference?

Click to expand...

Wouldn't do any harm to see what happens!!

Luxury is a descriptive term I used because I can assure you that when the ECU suffers an error the ride quality goes from "Luxury" to Harsh"

This is irrespective of the air bag being filled with more or less air

In "normal or no errors" mode the ECU makes constant alterations to each airbag determined by height sensors, air pressure sensors, vehicle speed etc etc etc and " fine tunes" the suspension giving a more luxurious ride

As soon as an error is sensed then the ECU stops doing its "fine tuning" and the road goes harsh

I can assure you that you will notice this change from Lux to Harsh if you have been driving your car for a while and then it goes harsh - it is more a sensation than a massive difference

Would not any error throw up an air suspension fail message? Why would some faults be acceptable if the ride quality was compromised? Interesting Thread

spitfire said:

Would not any error throw up an air suspension fail message? Why would some faults be acceptable if the ride quality was compromised? Interesting Thread

Click to expand...

Overheat of compressor does not cause error on dash

Whilst live data reading and driving vehicle the compressor went Overheat and ride went harsh - my theory on this is to conserve any air already in reservoir by not constantly using air to alter suspension

Ran it for 15 mins with the driver door open........didn't seem to make any difference to the ride quality.

I have a guy popping down tomorrow to reset the ECU.......if this brings back the luxury ride then at least I'm a step closer to finding out what's wrong.

When my compressor was overheating the EAS system logged a hard fault and displayed suspension inactive. And couldn't be reset unless you plug it into diagnostics