To keep things in the same topic folders, I thought I would post my question here:

I had to open my connectors on my level sensors and wheel speed sensors to clean the contacts and short harness to large harness to test for short/open pinpoint tests, and also replace the wheel speed sensors - one was showing defective so I typiclly replace in pairs..

Any case, height sensor disconnects requires recalibration.

However what is the sequence to perform recalibration using IDS as there are 4 main air suspension functions and then each has a various combinations front/rear or combination.

Looking at the Training program manual extract does not show the order of IDS air suspension feature to follow, for example, do I perform a Geometry first then calibration, of visa versa, or deflate rear then front, then geometry and calibration, or deflate front then rear, calibration then geometry?

I do not seem to find much sequence of setup in any manuals.

 

Hi StagByTriumph,

Since your question relates specifically to air suspension calibration, and not to the overall system description, I'm going to move your post to start your own thread.

I have not used IDS to perform an air suspension calibration on an X350/X358, so I do not know the procedure in that program. In SDD, the program walks you through the sequence automatically. You just need a metric-calibrated measuring tape or meter stick so you can enter the measurements from the center of the wheel to the fender arch. SDD tells you the order and performs the adjustments. I usually have to perform the calibration at least twice, and often have to "fool" SDD by exaggerating the measurement in one direction or the other to get SDD to increase its adjustment.

Cheers,

Don

 

Don,
Thanks for getting back to me quickly and moving my post to a better area.

My XJ8L is a 2005, VIN is G48653 with 103k miles.
I have been playing with both IDS125 and also ThinkDiag+. I'll try it with SDD - I think I have 138, but the ASM system is behaving erraticaly. Volts good and also on the diag power supply.

Somtimes the ASM will pump both rears up to max using the initial geometry setting, and I need to do a drive around, deflate rears, reinflate, everything seems normal. That worked for a little while,. but then both rr and rl deflated. So back on the level 4 post lift (ramp), rechecked level, performed a full system deflate, then inflated the tank, then performed a calibration (that is basically following TSB XJ206-06 procedures).

Now the right side seems to be over inflated front and rear +50mm out of spec and the left side front does not change at +10mm and now the left rear will not change inflated to 327mm which is holding some air, will deflate and had fully inflated with the initial geometry tool. Only ASM fault now is C2302 plausibility which is correct for the current geometry but I am not finding leaks ... yet. But the overinflation of the rears may have cmmpromised the bags or one bag.

I believe the initial geometry does the full height extension for some reason, no real information on that feature.

Whnever I run the Calibration, I get "failed to calibrate module, faults logged, returning to last values". I think that is the root problem as I need to be able to reset those default values to near to spec.

I'll try again tommorrow with SDD 138, try to run a new configuration on the module, then run through the XJ204-06 Air Suspension Diagnostics again.

I am thinking the valve block on the accumulator tank might be flakey or gummed up but I can hear it stroking and moving air in steps, and inflating when I do the initial geometry.

BTW, how do the hoses come off the valve manifold? I imagine those are typical push-to-lock pneumatic connectors and the center ring gets released to pop up somewhow? What does that tool or its alternate method look like? Or, are they compression with furrels?

thanks in advance for any more ideas.

Glenn aka StagByTriumph Garage

 

I use IDS V125 for the calibration, for me it works better than the V130 that I also have.

Normally I just start the calibration program and it runs you through the procedure, as already stated,

In March I had a defective rear height sensor that caused the car to rise to maximum height at the rear (as the rear shocks were also rock hard, it was not a nice driving experience for around 1,000 km).
The error code was C2302 (levelling plausibility error), as you have, which tends more towards a defective height sensor, than to a leaking shock.
When I replaced the sensor and started the calibration, I got an error message saying that calibration could not be performed because the rear was out of limits (or something similar). Fortunately, by using the deflate/inflate function of IDS for the rear shocks only, I could bring the rear to a height that was within the limits of the calibration program. Everything worked fine after that.

Best regards,

Thomas

 

Thanks Thomas, very helpful.

Yes, similar issues and experiences. I am also suspecting the height sensors are not supplying the correct signals OR, the ASM is defective. I'll be doing more pinpoint tests to see if the right/left are responding in opposite as designed and linear through the entire sweep.

The odd one is the right front which has no sensor that is starting to point me to the ASM, or at least the defaults loaded in the ASM.

I am also suspecting my problems may have started from a new battery I installed in December '23, that I suspect might be intermittently dropping below 12VDC and then back to 12.75+VDC under some circumstances, recovering and giving me red herings and wild geese.to chase, or that a low voltage occurance damaged the ASM. Current checks of the system do not expose anything consuming current during key off, but I also have replaced the alternator and starter when they failed at 103k miles.
That battery of course, when run through the new battery tests at the retailer shows it is fine, but my load test shows although in the "good" range, it is on the lower side - not bottom of the green.-good.

Ground points is on my to-do list too.

More pinpoint work is needed ...

 

Hi Glenn,

My first guesses as to why calibration might fail would be either suspension-related fault codes (DTCs) are stored, or the compressor is tired and cannot pressurize the system as quickly as the ASM expects, or you do have a problem in the valve block.

The hoses are secured with compression nuts and compression rings or ferrules that Jaguar sometimes refers to as "olives." You'll see all the brass nuts when you expose the valve block and reservoir under the spare wheel in the boot/trunk. The valve block has one pressure sensor (made by Denso).

Cheers,

Don

 

@Don B Your recommendation to use SDD made it a bit easier, certainly when I went to dealer setup and reconfigured the Air Module.

As I suspected, the Air Suspension Module needed to be configured to wipe out the previous calibration attempts that were giving me irratic readings and scenarios

New Configuration of the module reset to the factory / Vehicle Configuration settings, then automatically performed a height calibration.

What I learned is the calibration procedure does not adjust the vehicle height to the factory settings as I was expecting to see.

The calibration procedure verifies the sensor positions, THEN after performing a drive and parking on a level surface, the suspension will THEN adjust to the factory specs.

I watched it happen when I:

1. performed a module new configuration.
2. IMMEDIATELY, the system went into self leveling mode and all corners were "close" in measurement, but NOT at factory spec, level, but not factory spec;
3. verified and entered the height measuring with the ruler at centerline of the wheel (happens to be conveniently at the bottom of the growler's nose crease on the wheel center caps to the top underside of the wheel arch;
4. system then again "levels" but if no leaks or problems, no changes should be observed from the first measurements;
5. the second measurement verification purpose is to assure there are no leaks that would have changed from the first measurements in order to complete the calibration settings into the Air Suspension Module. If they are different, that indicates the system has somehow changed - leak, stuck valve, out of range sensor or something similar;
6. disconnect VCM, drove a route above 3km per hour;
7. returned to the level ramp;
8. key off
9. placed the measuring ruler at centerline of the wheel (happens to be conveniently at the bottom of the growler's nose crease on the wheel center caps) to the top underside of the wheel arch;
10. watched the suspension go to EXACTLY ON spec on the front and the rear within the first two minutes after key off.

Solved.

 

I will guess at least a couple of you are thinking, "ah sure, solved eh?" and you might be correct.

Further thought of the sum of the symptoms, I keep going back to the battery issue which may appear to have been the root of triggering the problem from low battery voltage, but probably not.

I am starting to think the air suspension leveling during key off may have been causing an additional battery drain over the period of 1-3 weeks of non-vehicle use, in turn triggering other issues caused by low voltage from the battery.
This then points to either an air leak which I have not been able to locate, or a sensor wiper defect in one or more position sensors that causes a temporary DTC plausibility error - probably at or near the factory specification position on the sensor causing wear on that spot. Then when the vehicle height is adjusted to a new position with a good sensor value, the temporary plausibility DTC dissappears and is not logged for that sensor.

The only pinpoint test would be to test the sensor through its full frange of movement and observe a dead spot in one position if voltage in circuit or resistance out of circuit is not linear or within specification.

I would hope the initial geometry test - or some other IDS/SDD provided test sequence would have checked the sensors for the linearity of each sensor from full front/rear deflate to full front/rear inflate and then flag a bad sensor DTC, but I cannot seem to find if one of the test scenarios actually perform that full range sensor test. Am I missing that test somewhere?

It would be great to find what the system does or is supposed to do if a sensor goes bad, like Thomas observed - the rears go to a full inflation and then trigger a height plausibility.

I am going to change out all three of my height sensors next, which after 103k miles is probably a good idea.
More after new sensors are sourced, installed and calibrated.

 

Hi Glenn,
I forgot to mention one thing, my apologies.
I have an iCarsoft that I always keep in the car, so when I had the problem in March, I checked the DTCs. At first, I only got the C2302 code, nothing else. I deleted the code and tried to do a hard reset of the car by connecting the battery cables, but all to no avail.
As we were on a trip, I decided to proceed to our destination, and tried again the next days. After a few more tries with resetting and checking again the codes, I finally also got the C1885 DTC, which indicated a faulty right rear height sensor. And replacing that also cured the problem.

By the way, I also suspected the battery, which is app. 2 years old, and/or the alternator, so on the trip I bought a charger and hooked it up, but it did not resolve anything.
After our return, I had both the battery and the alternator checked, but both were, and still are, fine.

My main point is that it seems that not all DTCs are shown immediately, so it seems advisable to check DTCs more than once.

Best regards,

Thomas

 

Good point, Thomas. In fact, at least some of the DTC Summaries manuals show that some codes require two successive drive cycles in which the fault is detected before the code is stored permanently.

Also, I don't know if it's been mentioned in this thread, but the most common cause of the C2302 code is probably a worn piston ring seal in the compressor preventing the compressor from pressurizing the system in the time alloted by the ASM.

For those who have not rebuilt their compressors yet, it's one of the best first things to do when air suspension troubles arise. Check the cylinder bore for scores or excessive wear, replace the piston ring (bagpipingandy makes excellent new ones), clean the rust from the the leaf valves, exhaust valve and pressure relief valve, and while you're at it, put the desiccant beads in a hot oven overnight to dry and partially reactivate them (or replace the molecular sieve beads).

Cheers,

Don

 

Hi Don,

you are right about the compressor. For me, it was not a suspect because I had already done the refurbishment with bagpipingandy's kit a few years ago as a preventive measure. No rust in mine, also the desiccant looked good, but then my car never ran in a particularly humid climate (Italy and Germany).

Best regards,

Thomas

 

@Thomas-S. and @Don B Yes, I have had those very same experiences you both mention.

The ThinkDiag+ I use is pretty useful as an interrm tool with a caveat the user needs to fully understand and be knowledgeable of the various diagnostics and what the tests do beforehand. If the ThinkDiag+ gets to where I need to dive in deeper I just go to the IDS/SDD (would be nicer to have my IDS/SDD 125-138 working with a wireless VCM instead of my Ford/JLR wired Rotunda VCM, but wired connection with an OEM VCM is always safest).

Some owners have reported methods to "force" DTC's like having a restricted performance and then driving past 3k RPM to lock in codes.

Odd the very first DTC that came up was RR wheel speed sensor short/open, triggering an ABS failure, then triggering a host of all sorts of issues from ECM to TCM and transmission fault and brake module - all of those of course were most likey a dip in the battery voltage from sitting and adjusting height with key off. Fortunately my reluctor rings are absolutely clean for the sepeed sensors, no accumulations of dirt/dust/debries/rust.

For the Air Suspension DTC's I have watched some DTCs appear - not latched in, then dissappear, not being able to catch a sensor DTC, just a plausibility DTC.

After a dozen individual resets from the original barrage of faults and deleting the flight recording I still do not have a sensor DTC. BTW I find if the flight recorder file and DTC left in place, it seems to cause a lot of other unreleated DTCs unless it is saved, deleted and reset.

Another annoying set of DTC's are the REM and the rear light cluster. It is low humidity in Colorado, corrosion of connectors is not really an issue. Yes, gotta do the grounds, pull the REM, clean all the connectors and check wiring .....

I think my height sensors DTC that I got once only for the right rear, just after the ABS RR speed sensor fault, and then took the connectors apart for pinpint testing, was not corrosion but a defective sensor starting to fail. Pinpoint is fairly static, go-no-go tests, not carefully observing the full height sensor dial sweep. At 103k miles, sensor failure is very "plausible" ..

Great discussion and advice gents!

 

Grounds are critical - the aluminum forms a very thin skin of whitish aluminum oxide that is an insulator, and hard to see until you remove the nut and inspect it an all the eyelet terminals. I use a small brass-bristle brush to clean the nut, all eyelets and the stud, and then flush them all with CRC QD Electronic Contact Cleaner.

Remember that the torque spec for most of the ground nuts is very low, off the top of my head just 6.5 ft. lbs., or just over hand-tight. Several of our members have discovered the hard way just how easy it is to pop a stud right off of the body by overtightening the nut...

Cheers,

Don

 

So while procrastinating to order the three height sensors and their connectors, I must say, (touch wood), that I have not had any issue since performing the calibration setup except one weeks ago now when the rears inflated to max and I had to do a deflate rears to get back to normal, so I will be ordering the sensors this week.
However with 103k miles, I believe the height sensors should be considered consumables and replaced when they begin to show issues, provided grounds, wiring and connectors are all checked first.

I do believe the issue was initially triggered by low battery voltage and a host of other bogus DTC's from that low battery voltage. Hot weather now and the battery issue will show its failure when the weather turns cold again.