Greetings! The front of my XJR is on the ground, but the rear is fine. I took it to a dealer, which ran the computer diagnostics and determined that I needed new front struts and a compressor. I took the car home and replaced the parts (new compressor and reman struts). When I reconnected the battery and started the car, nothing happened. When I backed it out of the bay, nothing happened. After idling for five minutes, the compressor started and ran for ten seconds, then shut off.

I drove it for a few minutes up to 30mph and ended up getting the air suspension fault. The front is still on the ground.

Did I miss anything? Was I supposed to "flip a switch" or do some special sequence of events to make it work?

When the dealer ran the codes, I don't recall anything else that showed a problem with any other electrical/suspension problems.

Thanks in advance for any input. My next step is to go to the dealer and beg for help (and throw lots of cash at them)...

 

You probably don't want to hear it, but I converted to coils. The air suspension was just too finicky to me and it left me stranded.

 

Haha...while I appreciate the advice, I just finished installing the brand new parts. Not converting to coils anytime soon.

Anyone else have some suggestions? Thanks!

 

You know at least it cannot be the compressor or the front shocks, in theory at least so long as they have been installed correctly. So if I had this issue I would start with the front height sensor. Dont know whether you have one or two? I would jury rig it lower and see whether that has any effect as a start. Are you still getting a fault code? Incidentally I love my CATS and would never change.

 

The 2004 has two front sensors.

 

My car only has one sensor, located on the driver's side lower control arm. And the car can't really get any lower. When I had my scan done at the dealer, there was nothing about the sensor being faulty. Maybe a kink in an air line?

 

If you lower the sensor the car should pump up higher at the front.

It just might be that the computer thinks the car is at the correct height.

 

+1

You could also look at the X350_Dealer_Training_Air_Suspension_Section docs here to see if they may help http://api.viglink.com/api/click?for...J8%202004-2010

 

Egads...those documents make it even more dismal! Some of the info talks about hooking up the diagnostic computer to the suspension module in the trunk, manually measuring the ride height at each corner, then entering in the correct values so the computer can properly inflate the new equipment.

Thanks for pointing out those docs. I'll try to "fake it" with the height sensor, then if it doesn't work, take it to the dealer.

 

Hi Paradigm,

The first thing I would suggest is that you read the section of the document hafren linked to that deals with Jacking Mode. It is possible your car has inhibited the air suspension system because it recognized that you had raised it for service and has not yet "awakened," though your drive that reached 30mph should have done the job.

Also, depending on when you disconnected the battery (before or after you raised the car to replace the air springs/dampers and compressor), the front height sensor calibration may have been lost, as jackra_1 mentioned. It may be possible to fool the system either by playing with the height sensor or by disconnecting the battery, raising both front wheels, reconnecting the battery, then lowering the jacks to see if the ASM will then inflate the front end after you've driven the car above 2 or 3 mph. (I'm tired and didn't spend much time thinking about this sequence and may have it wrong - hopefully someone will correct me).

As jackra_1 suggested, it is possible that your original problem was an issue with the front height sensor, causing the Air Suspension Control Module (ASM) to believe the front was at the correct ride height when it was actually too low.

It could also be a problem with the valve block in the trunk that apportions air pressure to the four corners to maintain the correct ride height.

Another possibility is an air leak in the system affecting the front end only.

In any case, the piston ring in your old compressor was almost certainly worn and not pressurizing the system as quickly as it was supposed to, but that could have been replaced with a new ring from our forum member bagpipingandy for £25.00 / $38.00 plus postage and a little labor....

To see how the dealer-level System Driven Diagnostics (SDD) system is used to level or otherwise adjust the ride height, see Cambo's post here:

https://www.jaguarforums.com/forum/x...e3/#post531488

Cambo shows how to fool the Air Suspension Control Module in order to lower the ride height, but the same principles apply in establishing the factory specified ride height.

Now that you have the ASF, you should have at least one Diagnostic Trouble Code (DTC) stored, which will be C, B and/or U codes that require the dealer-level SDD system to read. If following the instructions for exiting Jacking Mode or the height sensor or battery disconnection ideas don't work, it would be time for another trip to the dealer to have the codes read and to give them a very hard time about selling you those expensive parts that have not corrected the problem....

If you do get some new codes scanned, please list all of them here (including the initial letters, as in C1723, B2810, U1900, etc.) so our knowledgeable members will be able to see the "big picture."

Cheers,

Don

 

If it ends up being a ride height sensor I have some sitting around I'd be willing to sell from my conversion. Something tells me it just needs recalibration though.

 

I put Arnott's on my 2004 XJR a few years back and have been very happy with them. Installation was easy to do and delivery was within a few days. Now have 102K miles on the car and the originals are still on the rear as well as the air compressor.

RyeJag

 

This might be worth trying:

Key off

Break joints to release air pressure until complete system

is depressurised.

Remake joints.

Disconnect both battery leads and touch together

Replace battery leads.

Run engine.

If the suspension partly lifts listen for leaks.

If the suspension does not lift if possible drive vehicle for up to 20 mins.

No guarantees but it has worked in the past.


Don't go back to that dealer because I suspect that they don't know what they are doing.

 

Have you checked the R1 relay and fuse#6 in the engine bay. My fuse was blown