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Hello all,
Recently purchased "JackieO". All good til recently I experienced the dreaded Air suspension fault error. However, it isn't leaking or dropping. My issue is isolated to the rear and the problem isn't too low, but too high.
When I go over a bump even very slowly, the front end operates as it should, but the rear goes over and it is extremely stiff (like you were riding on an axle). Additionally, the car looks higher in the back. I have obtained a dealer training book (X350_Dealer_Training_Air_Suspension_Section). Though, it does not give options for trouble shooting.
I had it scanned, but it was not at a Jaguar dealership, so I don't think the scanner used can read everything for jags. P1111 (completed diagnostic scan) was the only item found. I called the dealership, but they have not called back yet (go figure). I do not know much about the system, but is there a way to maybe reset or let the lines out by the valve block to release the pressure built up? I'm thinking it is just crossed up and needs a little reboot sort to speak.
I know it would be more helpful with codes, but this is all I have so far. I have had the car for about a year and have not had any issues. Well, the blower motor for the ac is starting to go, but that isn't a front burner issue and I have a pretty good idea of what and how. This issue has me stumped. Any help is greatly appreciated.
To answer one of your questions, a standard OBDII scanner can read the P-prefix (Powertrain) codes, but it cannot read the proprietary Jaguar codes associated with with the air suspension, which are C-prefix (Chassis), B-prefix (Body), or U (Undefined, mostly network-related) codes. Knowing the codes that are stored would probably help speed the diagnosis.
If only one of your rear air springs was high I would first suspect the ride height sensor for that corner. But if both rear air springs are too high, it is unlikely both ride height sensors are malfunctioning. One possibility is a problem in the valve body, which apportions pressure to each rear air spring independently, and to the front air springs either independently (early cars with four ride height sensors) or together (most X350s with only one front ride height sensor).
The ride height can be adjusted at all four corners using a dealer-level diagnostic system such as IDS or SDD, but the trouble codes may help explain the cause of the problem.
Thanks Don. The issues seemed to have corrected itself while sitting in the driveway. I have not had time to get to a place that can scan for the Jag codes. I know this is going to shed a lot of light on the subject.
I noticed it was not jacked up in the rear today, so I decided to drive it and see if all the issues were gone or just hiding. They were gone until the very end of driving. The air suspension fault msg appeared on the dash, the ac stopped working (think have isolated that to a blower motor), and the back end started to stiffen up and fill/rise up. I was close to home so was not bad to drive home.
You mentioned the valve body being a potential culprit. Where is that located? It seems there is some break or loss of communication with some components. I know I am kind of spit-balling in the dark until I get codes, but just trying to learn the lingo of the components within the air-suspension system.
Btw, when I did get home I turned off the car for a minute. Turned it back on and could hear the compressor kick in and could see the rear end rising all the way back up as it had been prior to "righting" itself.
I noticed it was not jacked up in the rear today, so I decided to drive it and see if all the issues were gone or just hiding. They were gone until the very end of driving. The air suspension fault msg appeared on the dash, the ac stopped working (think have isolated that to a blower motor), and the back end started to stiffen up and fill/rise up. I was close to home so was not bad to drive home.
If the blower motor quit the first suspect is the Blower Control Module (BCM). A new revised BCM with longer heat sink fins is available from Jaguar, or you can rebuild yours with a new heat sink as I did:
You mentioned the valve body being a potential culprit. Where is that located? It seems there is some break or loss of communication with some components.
The valve body is in the trunk, under the spare tire/wheel and a sound-deadening foam cover. That is also where the air reservoir is located. Jaguar says the valve body is not serviceable, but you can clean the electrical connectors for the valve body and pressure switch, and also clean the ground studs in the trunk (the torque spec for the nuts is just 6.5 ft. lbs. so don't over tighten them!). Here's how I clean grounds (the photos are of the ones behind the headlamps but the same principles apply to the ones in the trunk):
Thanks everyone so far. I have a 3rd vehicle so thankfully I have not been stranded, thus the lack of desire to rush out and spend money on the repair. I haven't had time with work so I broke down and took to a shop. They tried clearing the codes as Meirion1 suggested. The error message states "rear struts out of range". It won't even level itself when he resets. Called Jag and they said sounds like sensors in rear struts are bad, so to START with replacing the two rear struts and go from there.
Is this odd to not know for sure what the problem is and to advise to "start" with parts? The shop said that the sensors are in the struts so they cannot be serviced, hence the need to replace. He is waiting on pricing for struts. He broached the subject of changing the air suspension system completely, but said lets wait to see cost. He was "irritated" by the suggestion of just starting with replacing a part and not having a definitive idea as well. Any thoughts?
If by 'struts' he means the air springs (commonly called air shocks) then at best he's confused or at worst he's misleading you; the height sensors are not in the struts.
The height sensors are mounted on the body of the car and linked to the upper wishbones of the suspension. Yours may have four or may only have three; the RH front sensor was deleted fairly early on.
The wires going into the top of the suspension unit (visible on the front units if you open the hood) control the dampers, making them 'hard' or 'soft'; that's the CATS system. If he tries to tell you they are the height sensors then walk away and find another dealer/shop.
Last edited by Partick the Cat; 08-19-2016 at 03:00 PM.
Evidently, the sensors that he is referring to are not the height sensors. The sensors in question are actually inside the "struts"/ air shocks. He left msg saying factory air shocks are $1311 a piece. He is of the opinion of doing a conversion. Cost is $2200 total for him to do conversion and get car off air springs altogether. I am pretty certain I won't be looking at putting in new air shocks. The question now is do I let him do the conversion, go somewhere else, or drive the damn car into a dealership and be done with it.... Oh, btw the blower motor for ac is shot. That plus a resister he said would prob be needed too. I know the blower motor was going so not surprised but didn't know the resister would be needed to be replaced. I have owned it a year. Paid $5000 for it. Was something to placate the wife with. Now do I put $2700+ into a car I only wanted for 3 years for the wifey? I know what the wifey will say........ Any guidance from the experts and lifelong jag enthusiasts on here would be really be appreciated right about now!!
I haven't had time with work so I broke down and took to a shop. They tried clearing the codes as Meirion1 suggested. The error message states "rear struts out of range". It won't even level itself when he resets. Called Jag and they said sounds like sensors in rear struts are bad, so to START with replacing the two rear struts and go from there.
Hi JackieO,
It might be very helpful to know the exact fault code that was discovered by the shop that scanned your car. "Rear struts out of range" is not Jaguar terminology. Also, when you say he reset the system, do you mean he cleared the fault code, or did he level or recalibrate the air suspension using a Jaguar IDS or SDD diagnostic system?
As Partick the Cat explained, Jaguar calls each of these units an "Air Spring and Damper," because they combine an air bladder that replaces the conventional coil spring, along with an adaptive hydraulic shock absorber (damper in U.K. lingo) that can switch between Hard and Soft damping rates under the control of the ECATS control module built into the Air Suspension Control Module.
You can download the Air Suspension & ECATS section of the Dealer Training Manual here:
As far as I know, there is nothing inside the air springs that can cause your symptoms, with the very unlikely possibility of a stuck pressure retaining valve (PRV). The PRV is designed to maintain a minimum of 43.5 psi in the air spring to prevent creasing of the bladder that could lead to damage. If the PRV was holding more pressure than it should, you might have a high ride height. But it seems highly unlikely that the PRVs in both rear air springs would malfunction at the same time and in the same fashion.
One thing worth trying on your suspension would be to do a hard reset of the system by disconnecting the negative battery cable and holding it in contact with the positive battery cable for a couple of minutes. The positive cable can remain attached to the battery.
If that doesn't work, it might be worth another test. With the negative battery terminal disconnected, locate the brass air line fittings on each of the rear air springs (behind the side carpeted trim in the trunk, near the forward bulkhead/rear seat. Slowly loosen each fitting just enough to let as much air escape as possible, then gently retighten each fitting - do not overtighten!
Reconnect the battery negative cable, start the engine, leave the transmission in Park and allow the compressor to run. Hopefully the rear end should rise to normal height. If it rises but does not achieve normal height, turn off the engine, wait 45 seconds, then restart the engine and allow the compressor to run again as long as it will (up to 2 minutes). Let us know the results.
Regarding the Arnott coil conversion, I've done a couple of them and the owners have been very happy with the results. The kits are $1338 with free shipping on eBay, and the job will take about 5-6 hours including installing the Electronic Bypass Module (EBM) and clearing any residual diagnostic trouble codes, but not taking into account any seized fasteners or other problems that may be encountered.
Do you know which of the two rear struts is shorted out internally? Note that I have a rear shock for sale cheap in the Classifieds section (that I am certain is not shorted out internally) The donar (our VDP) has never been hit.
Previously, I had bought some used rear air shocks from a low mileage XJ8, and the rear suspension stuck in the hard mode as soon as I installed them. I cam to find out that one of the two rear air shocks was electrically broken internally (if I recall right, no resistance across the two pins, you can check this in the trunk where the tops of the rear shocks bolt through).
Ended up finding out the donar was a hard rear hit and returned that pair for a full refund.
Anyone know what the fix was? I have a C2302 plausibility error and the car is jacked up in the rear. Replaced the valve block and tried swapping the control module - it didn't fix it.
Hi Don,
I have two similar 2004 x350s, one a donor car for the other. My daily driver had to have the front two air shocks 'donated' (I refurbed the donor ones with rust treatment, spray paint and new bearings) as they started 'blowing out' going over speed bumps and the system stiffened them. Now the same thing is happening in the left rear and the right rear is compensating by lowering (although on a downward facing hill in Park they will inflate again). I've refurbed the first of the two donor rear shocks however they had been fully inflated because of a snapped left-rear height sensor and remained so even after removing them from the donor car. All was going well last night fitting it to the daily driver when I realised I can't bolt up the lower suspension arm after tightening up the 4 x strut mount bolts in the boot as the shock bearing protrudes 2" below the suspension arm. I thought I was clever and wired up the shock with the air line and new o-ring and ran the JLR SDD software to align everything again (I had done this successfully before with the front shocks) but the system has an air suspension fault and the Service function just cycles the air compressor every few minutes. Should I 'reset' the air suspension or 'deflate' the system using the SDD? Would this release the valve in the donor left rear shock to allow be to bolt it to the lower suspension arm?
I think I understand your dilemma. If you disconnect the air hose from the air spring, it may be possible to then compress the spring using a floor jack on its lower end. I also have often had to use a long lever on the upper wishbone or control arm to lower the suspension to help align the shock bolt hole with the hole in the arm. Be sure to disconnect at least one end of the anti-sway bar link or remove it altogether. This will give the suspension some additional freedom to move downward. You may find some helpful tips in this post:
Hi Don,
Your advice was super and gave me the confidence to lower the rear suspension using an alternative method (see below - good old 4" x 4" fence post allows a 1-man job)!
The suspension arm at its lowest point though was not low enough so using the worm screw jack compressed the shock enough to get the lower suspension arm bolt in (notice the drop link unbolted as well as the rear stabiliser bar to make life easier). However the shock was too extended and couldn't bolt back the drop link and stabiliser bar. So I then put the wheel back on and slowly lowered the car and watched the shock compress under the weight of the car. So tomorrow's job is to take the wheel back off and bolt up the drop link and stabiliser bar, take the car for a short spin to remove any hint of Jack mode then re-align the air suspension using JLR SDD.
07-15-2016, 05:26 PM
2004 XJ8 rear suspension too high
