I've had this issue on and off for several years. My 06 seems to have a mind of its own when it comes to the front suspension height. Seemingly randomly it will raise the front higher than normal, though it actually is not out of spec (400mm). I had posted a long time ago about the same issue, but maybe someone else has seen this happen. Last time I went down the rabbit hole of checking the wiring to the front height sensor, powers and grounds to the ASM, all of which are fine. Recalibrated using SDD which didn't have any effect on this intermittent issue.

I recently replaced the rear air springs (fronts were done several years ago), now the problem seems worse. I suspect because there are no air leaks the system has more air to work with and can raise the front height.

1. The issue seems to occur most after the car sits a few days (up to a week) without being driven. It will sit forever in the garage at the correct height. When I start the car the height is normal, but after I've driven a mile and the compressor runs a bit, the ASM jacks up the front to 400 mm. It will then sit there at the absurd height for hours while parked.
2. As soon as I restart the car and move it a few feet, the front drops to the correct 386 mm height.
3. Technically speaking, 400 mm is within the 15mm tolerance of the front suspension (386 mm +/- 15 mm). I'm not sure if this is some function the ASM is doing on purpose, or if it's a fault. The rear is always the correct height.
4. I drove the car today, having driven it yesterday, and the ride height was normal from start to finish.
5. In the past, I've seen the front raise up even when daily driven/multiple trips. No rhyme or reason.
6. No warning messages, errors, or codes

Thought of changing the front height sensor just to see if that makes a difference. I've not heard of anyone else experiencing this issue, even if the car is not driven frequently.


Front extended to 400 mm

Front high, rear normal

Normal height (385 mm) after drive. Car will stay at this height parked in garage for weeks.

 

There was a post some time go about a bad connection on the ASM behind the back seat,

I don't remember the symptoms.

Also possible ASM failure
https://www.jaguarforums.com/forum/x...-fault-176969/

 

I think there are only a handful of EX - Jaguar engineers extant who REALLY understand how our air suspension works. (maybe it's so complicated that no one ever really understood it) Mine has always done random things and I have just learned to ignore it. Actually I've learned to enjoy it because it's characterful and interesting.

Sometimes when I get home from a drive (mostly a 30 mile run from work) the front is high, or all 4 corners are high. But not always. Typically after 30 minutes parked it vents a 5-10 second burst of air out the front vent and settles down to a lower height. Except when she feels like doing this right after I remove the key. Sometimes I will come back from parking on a bumpy surface and one end or the other will be 2 or 3 inches in the air! Why? No clue. Typically, any time the car is started and driven above 30mph, I can hear the compressor kick on for 10 seconds or so. But not always...Sometimes when I back out of the garage and get out to move a plant or garbage can or other obstacle out of the way I will hear the pump kick on and the car will raise up a bit. Mostly not...

If I was getting concerned every time this car does something weird with the air suspension I would have lost my mind by now.

Jeff

 

Thanks--the connectors along the CAN bus are worth looking into for any corrosion issues, though no network codes on my car.

This other thread just popped up from wwr https://www.jaguarforums.com/forum/x...t-high-251697/

Perhaps the next best step is to get something like the Foxwell that can read ASM live data. That would certainly narrow the diagnosis, if the front height sensor has noisy output or is reporting incorrectly that would cause my issues. I have SDD but it's just too cumbersome to take with me on test drives to monitor live values (I'm not sure I was even able to get to the portion of it that shows live data).

Also worth noting that Jaguar didn't even design the ASM, all of that came from Wabco. I'm sure Jag collaborated to get the functions they wanted, but they didn't build the system from scratch.

Some good direction--I'll post back if I figure out anything.

 

Can you please guide me on the tools and how your recalibrated your height sensors with SSD?

 

Would be better if you started a new thread on that topic, more members may read and respond.

Short answer is: you will need to first set up SDD. Once in there, Service Functions, Suspension Calibration. Just follow the steps on screen. You measure between each wheel hub and the top of the fender arch. Enter value in mm as prompted. SDD will raise/lower the car, request you start/stop engine, etc, enter numbers again and done.

 

My 2006 was worse back in 2015 when I purchased it.sometimes the rear was 3 - 4 inches high in the morning. Some said the driveway slope causes it. But driveway does not slope this much. Always fairly level.
Only once I was driving and front end rose a couple inches and and dropped down while sitting at a stop light. Several times. Felt like rear was moving around also. Sitting in traffic did not get out to investigate. Thought major crap was coming, but never noticed it again.
Did have a rear sensor come apart while swapping a rear strut. Rod just popped from boot. lubed up and popped back in. Worked perfectly. You might manually check for play in sensors. Since your car only has one on front, might be workwhile to swap.
My A8 mysteriously rose an inch on drivers side. Front and rear. Might have the same system. But the Ross Tech system will adjust. Finally bit and decided to “fix” so car was level.
It is a nightmare. On calibration the corners rose and dropped several times. Then would settle at random heights. Did this for two days. Never could get it back to correct. Wanted the front down a half inch and rear normal. Must have measured and entered heights 25 times.
Finally car threw a ride height code, and calibration quit working. But, it is slammed about 3/4 inch all the way around. Been driving for a year like this. The ride height adjustable headlights get height to set, so this does not work.
But looks 100% meaner lowered. Figured next step was pull gloves compartment and clean connector to ride height module. Might be a Wabco also. Passenger front corner had water entry several times from plugged sunroof drains. Could be it got wet.
But also knew if started working again , it is very wacky. Decided to drive slammed.

 

Was reading through the ASM training document, it turns out the tolerance for driving mode is not +/15mm, it's actually only +/-9, and then stance mode (after exiting the car) is even tighter at +/-6mm So in fact my car is out of spec for driving.

I'll probably start with checking and/or replacing the front height sensor. I'm doubting a CAN error since the TPMS, ASM, and parking brake module all share the same connector under the console to the CAN and I have no issues with those systems.

A flakey sensor is starting to make more sense, as after driving (e.g. moving the sensor) it resolves the issue. I wouldn't expect a hall effect sensor to have an issue like that, but now reading about other vehicles with such issues it's not such a long shot. If that fails, I'll have to get SDD data or another scan tool to see what the ASM data is actually reading.

 

Wanted to post the resolution to this issue: I bought a Foxwell NT530 with the JLR software package (pretty good deal at $150 USD), which can read data from all the car's modules just like SDD. Unlike SDD, I don't have to drag out a laptop and try to navigate a slow & intractable UI while operating the car. Very quickly determined that all the height sensors were reading correctly, but that the car could not lower. In fact it had stored a code C2302 for leveling plausibility error (though never flagged a Air Suspension Fault message).

Took apart my compressor and found the exhaust valve was stuck solid with corrosion. I cleaned that up and replaced the desiccant, the car has been leveling normally since. Very happy to see my compressor can still quickly build 175 psi as well.

Worth having the right tools for the job!


Ignore the three circuit codes, these are from were when I unplugged the harness to the front body.


Heights are actually in mm, not m.

 

Glad you found the issue, always appreciate members coming back to post what they find. Might give that Foxwell unit a try, seems great for the price.

 

hello mhamilton. I’ve got the same problem. Could you please tell me where you measure from to ascertain the ride height. I’ve got 71cm from the floor to the top of the wheel arch . But I’m obviously measuring in the wrong place. Thanks in advance.

 

I think the measurement is taken from the centre of the wheel hub.