Hey y'all -

So I had a ruptured front right strut. Got my indie to install the new Arnott unit and put on brakes while he was at it.

So far so good. Almost.

Except the car won't raise up. The compressor isn't turning on at all. Checked the fuses, they're fine.

I know the compressor and air system worked a few days ago, because I raised it up to get it on the flatbed.

The front tires are almost resting on the fender liner and won't budge.

Most puzzlingly, there is no warning light. No "Air Suspension Fault", no "Vehicle Too Low".

Any ideas out there? I'm baffled.

Thanks in advance.

 

This is a well-known syndrome but the exact answer eludes me. I think if you trundle around for a bit at low speed it will eventually raise itself, but wait for somebody more expert to confirm.

 

Start the engine and drive around the block for up to 20 mins.

 

Hi naterator,

I'm certainly no expert, but like Fraser and several other members I'm trying to learn everything I can about the air suspension system, so when others like you have a malfunction, I go back and study the documentation in my library to see if it offers any possible help.

In addition to the X350 Workshop Manual, which is available for download from this forum in six sections, I have a printed copy of the 2004 Model Year New XJ Technical Introduction Service Training Course manual, which contains some helpful info.

The most relevant thing I can find in this manual is the suspension behavior when it is in "Jacking Mode" (one of several modes in which it will operate). From page 7-23 of the manual: "The system recognizes customer vehicle jacking and vehicle ramp operation." I believe that in this context, the term "ramp" is the British expression for a "lift." Perhaps Fraser can confirm or correct.

"The result of detecting either condition is to inhibit any corrective action from height changes where no response is detected.

"If the system lowers the air suspension but no reduction in height is achieved, the system will time out at approximately 10 seconds.

"If all four height sensors change by preset values, the system will recognize the vehicle is being lifted on a hoist and initializes the inhibit function.

"Inhibit mode will continue to exist unless the vehicle height returns to normal or a wheel speed signal 2 m.p.h. (3 km/h) is detected. [bold added by me for emphasis - also, there is no mention of how long you need to drive above 2 mph]

"The above events are triggered by either the height sensor arm change in position or a wheel speed message on the CAN bus."

There is no mention in the manual of a DTC being logged when the system is in Jacking Mode.

If driving your car above 2 mph doesn't reactivate the air suspension/compressor, the next thing that might be worth checking would be the front height sensor(s) to ensure it/they were not disconnected by your mechanic while he was replacing the air shock. Note that up to VIN G26871, the X350 had four suspension height sensors, but from VIN G26872 the right front height sensor was omitted (see TSB XJ204-05, available for download from this forum).

Please let us know if any of this info helps.

Cheers,

Don

 

All of this information is absolutely helpful. Really appreciate it.

My VIN is G11290 - so it looks like I've got the four sensors.

My indie said that he drove it around for a little while - but in the area, the best you can do is stop and go traffic on the main roads. I'll try to crawl along the side roads tomorrow.

Fingers, toes, eyes, and legs crossed!

 

Well, that was it! Mechanic drove it around the block for a little while and we're good to go.

Thanks again guys. You all are awesome.

 

Congratulations naterator, and thanks for reporting back to let us know it worked!

Cheers,

Don

 

It can some time for the reservoir (in the boot) to pressurise if you have fully purged the system of air.

So running the engine a few times (or driving around the block) can fix it.

The correct thing to do is check/adjust the height sensors in SDD.

The bad news is you probably have a compressor that is worn but can be fixed easily with andy's repair kit

Another way around the problem is to pump up the reservoir using your shop compressor. It wint get up to full pressure (220psi) but will be enough to have the system run normally from the outset.

All you need to do is add a T fitting and tyre vavle to the compressor line. The best place is at the valve block. This will allow you to fill the reservoir prior to powering up the system. Its also a good backup in case of failure on the road

Cheers
34by151

 

Hi 34by151,

Note that naterator's compressor was not running at all, which led to the diagnosis that the system was inhibited because it had entered Jacking Mode.

Cheers,

Don

 

Nice to know I had remembered it correctly !! I do find my memory is not what it was.

 

To be more clear
You can get away with it if the compressor is in good condition.
Its caused by the pressure being below minimum for too long
The result is the mode change and compressor shutdown
It will appear dead when it goes into that mode.

You can do as above or just reset it with SDD in the first place.
SDD will prevent this from happening in the first place

This just tells the system to refill based on a less than minimum pressure

Most are familiar with the normal timeout. This is the time to get to max pressure. The fault here is the time to get to minimum pressure


Cheers
34by151

 

Hi 34by151,

On our '04, if the compressor runs for the allotted 120 seconds, then shuts down to prevent overheating of the piston ring and cylinder (per the manual) before minimum pressure is achieved, the engine can be shut down and restarted and the compressor will run again for another 120 seconds. This process can be repeated as necessary, allowing at least 30 seconds between runs for compressor cooling (the manual states that the ASM typically provides 30-40 seconds for compressor cooling, up to a maximum of 120 seconds).

But naterator reported that his compressor wasn't running at all, and he made no mention of having attempted to drive the car. This prompted Fraser and meirion1 to recommend that he drive the car, and I looked up the info about Jacking Mode in the manual, which seemed to confirm their recommendations.

Granted, at this point in time I would agree that any X350 that hasn't had a new piston ring needs one. But was there something in the information provided by naterator that led you to conclude his issue was compressor timeout before minimum pressure was achieved as opposed to the ASM having entered Jacking Mode?

Thanks in advance for any clarification. We're all trying to learn here!

Cheers,

Don

 

Don, I have an 04 XJR as well

The ASM has a number of inputs that it uses to detect faults.
The main one is the pressure sensor (in the boot) and on start-up to a lesser extent the height sensors

The asm also provides power to the relay that in turn powers the compressor

You are correct about he 120 seconds timeout. This is time the compressor is allowed to run in order to get the reservoir pressure up to the max limit

If the ASM reads above the max it will open the purge valve

There is another check that will disable the compressor.

When the ASM starts (ign on) and before doing anything else it reads the pressure sensor. If it is below minimum pressure it will give the compressor a very short burst. This should cause a very slight rise in tank pressure. If this does not occur it will shut down the compressor and not retry unless the car is moving.

This how the fault was resolved but it can also be done via SDD

When moving it will burst the compressor. When it detects the pressure is responding (ie rising) it will run the compressor for longer than the 120 seconds to get to minimum pressure.

I have somewhere how long this is and what the minimum is but from memory its 85psi and 240 seconds

Once this condition occurs (min pressure) you will go back into normal mode
IE the 120 second cycles

There is a 3rd mode which is the jacking mode as described before hand.

Oh yeah the ASM will also bypass this if you have the transit link in

Cheers
34by151

 

Hi 34by151,

Fraser and I have found some differences in the literature we have in our libraries, and I'm wondering if you and I are also encountering some differences between your literature and mine. I have the undated X350 Workshop Manual in pdf form (available for download from this forum), which contains information on servicing the air suspension system, but very little information on the actual operation of the system. I also have a printed copy of the Jaguar Service Training Course NP04, 2004 Model Year, New XJ Technical Introduction, which was used to train Jaguar dealership mechanics in anticipation of the X350 launch. This manual contains a fairly detailed explanation of the air suspension system and its operation, though I would not call its coverage "exhaustive." I also have the booklet describing the Wabco ECAS system, on which Jaguar's suspension is based (ECATS appears to be nothing more than an adaptation of ECAS).

I can't find a description in any of my manuals related to the startup compressor behavior you describe, with the short burst and the check for a rise in tank pressure. I would be very grateful if you could cite the source of that information because I'd like to add that source to my library if possible.


Again, I can't find any mention of this compressor burst and I'd be grateful for the source of this info. Regarding compresor run time, according to the Service Training Manual, "Another important point to remember is that the compressor only operates for a maximum of two minutes to control piston and cylinder head temperature." In the X350 implementation, there is no temperature sensor mounted on the cylinder head as there is on many other vehicles that use the Wabco compressor (including Andy Fulton's Audi Allroad). Instead, Jaguar simply limits compressor run time to a maximum of 120 seconds at a time, with a mandatory cooling period determined by an algorithm in the ASM's programming, with a minimum of 30 seconds and a maximum of 120 seconds to cool before the compressor will run again.


The Service Training Manual lists no fewer than 14 operation modes of the air suspension, each with its own set of behaviors:

Sleep mode
Preliminary mode
Post mode
Stance mode
Drive mode
Speed lowering mode
Transporation mode
Jacking mode
Inclination mode
Trailer mode
Curve mode
Geometry mode
Vehicle too low mode
Gross Vehicle Weight mode

One of these days I hope to scan this Service Training Manual and upload it, if I can find the time!

Cheers,

Don

 

Don, I would love a digital copy of the training manual you have. Hope you find time! :-)

During the measurements on my car it didn't see the behavior 34by151 describes BUT if it's a very short test I may have missed it.

I did notice the compressor runs more often without the mentioned interval if the pressure is really low. My assumption is the system prioritizes to keep the car level during a malfunction over saving the compressor.

Guus

 

Guus,

I counted the pages in the air suspension/ECATS section of this training manual and there are 28. Since the air suspension is by far the most commonly discussed system on the X350, I will find the time to scan those pages into a pdf document. I know how to attach a pdf to a post to this forum, but it would be great if I could upload it somewhere it could be easily downloaded. Any suggestions?

Cheers,

Don

 

Hi Guus,

Guess what? Tonight I scanned the 28 pages of the Air Suspension & ECATS section of the Jaguar Service Training Course NP04, 2004 New Model Year, New XJ Technical Introduction manual, but the pdf file is 10.9 MB, just a little larger than the 9.54 MB size limit allowed by the Jaguar Forums.

Does anyone have any ideas of where I could upload this file so you and others can download it at no cost? I'll contact Jim about the possibility of uploading it to the Jaguar Forums mediashare account.

Cheers,

Don

 

Thanks Don, I'll check if it's possible for you to drop it in my Dropbox.

Guus

 

Don, ill see if i can find it for you. Im heading to Europe tomorrow for 2 months so I do my best to find it for you before I go

Cheers
34by151

 

Thanks to Guus' encouragement, I scanned the Air Suspension & ECATS section from the dealer training manual. Jim was kind enough to grant approval for uploading the file and he put me in touch with Graham, who has uploaded the file to the Jaguar Forums download area so everyone can access it. See my new thread at the link below for the upload locations:

https://www.jaguarforums.com/forum/x...8/#post1014257


Special thanks to Guus and Thermite for their encouragement and helpful information.

I'll be interested in everyone's thoughts on this document, and if you have additional information that has not yet been uploaded, I would encourage you to do so since we are all trying to master the X350 air suspension so we can keep them functioning at intended. I hope that when 34by151 returns from his trip he'll be able to add his reference too.

Cheers,

Don