Member Since: 19 Dec 2022
Location: Roma
Posts: 35
Suspensions, obviously
Hello proud D3 owners.
For a moment I lived the dream that the D3 was a normal car. I had nearly forgotten the evil “ping”, the dashboard going Christmastime and the D3 deciding that not being a car keeps me safer.
It must have realised I was living too quiet a Life and right at the beginning of the summer, there goes a new present!
The event
A week ago. The car was parked from the night before on a flat spot, as usual at its driving height. I turn the key in/engine off to roll down the windows before letting the dogs in and the D3 goes right down on the bump stops, with the red warning light and maximum speed warning 50km. This happened in the countryside. To go back home I had to drive about 10km on bumpy gravel and about 300km tar road. Several times I stopped and tried the old “switch off and on again” trick to no avail. Since then, the car has been sitting in the driveway, lifeless, basically an overweight, Tonga green, boxy Ferrari. Until the event I had never had any warning or issues with the car.
The diagnosis (Autel MaxiAP AP200).
From the riding height module, I only have errors on all four sensors [C1A72-1C, C1A73-1C, C1A74-1C, C1A75-1C; height sensor mechanism - permanent]; I have various other things about the lights (the AFS light flashes) that according to what I read on the forum should reflect the levelling problems caused by the errors to the riding height module and codes from other modules about invalid signals received from the riding height module.
Live data.
Height sensors: 4.9V input and 0.peanuts output; control module: 13.8V voltage and 1000A current; pressure sensor 4.9V; Compressor voltage: 0V; current of all valves: 0A; valves all closed (at least I think, the message says “valve percentage – open: 0%”, but the translation in Italian of a statement in English made by a Chinese might well become the contrary). I checked the 3 fuses and the relay in the BJB associated with the suspension system and everything is ok; battery seems to be working fine. When I turn on the engine I hear a click-clac from below, around the compressor, which I think is the valve that settles, but the compressor obviously doesn't start. For various reasons I have still not been able to lift the car and iti sitting too low to jack it up with the standard jack.
Before stripping it apart, I wanted to share some thoughts hoping in a summer-saving advice.
1. Before that, I never found the car down, not even after long stops (I mostly use it over weekends for long drives). The event described above occurred with the engine off; the car was perfectly in shape and lowered as soon as I switched the key on. I would tend to rule out leakages with the air struts or the lines from the valves to the struts.
2. While I don't understand why the valves opened all together and discharged the struts when I switched the key on, I think the compressor should have nothing to do with it. I searched for info on how precisely the system works and what happens when the key is switched on (what kind of checks are run and responses given), but I couldn't find anything to help me understand.
3. Diagnostics (repeated several times) never gave errors related to the compressor or valves. Only and always the 4 sensors (with mechanical problems). The workshop manual says that the car goes on bump stops if: (a) water ingress (excluded); (b) air leakage (reasonably excluded); (c) vehicle in transport mode (should have done it on its own!); (d) calibration failure (it should have happened while the car was parked); (e) implausible articulation signals (even here I don't know, since the car was as always); (f) multiple failure of height sensors (it would be bad luck, also because it would have happened while it was parked since no warning had been issued until last drive!) ; (g) failure of the suspension control module (of which I have no indications from the diagnostics).
4. I couldn't figure out if one would see some diagnostic signal (apart from the lack of voltage) if the compressor was gone. In any case, based on what the manual says and on how things went, I would exclude the compressor, at least in the first instance, since all began with the suspensions deflation as if they had received a signal during the initial routine checks.
I searched extensively the forum (ITA and ENG) and it seems to me that all the cases of red light and bump stops occurred either while driving or after it was found on the bump stops or crooked after a parking spell. I didn't find cases similar to mine where it went on the bump stops upon switching the key on, with no previous warning, and from a normal riding height.
Any insight from the experienced owners?
Do I change the diagnostic tool, the car or the holiday plan?
Many thanks
29th Jun 2024 9:44 am
Grumpydog
Member Since: 10 Apr 2019
Location: Medway/ Mos Eisley
Posts: 161
Ah, a suspension fault, good luck!
Firstly, with everything being linked by a CAN network, any fault in the system will be enough to disable the suspension. I had a locking rear diff motor fail. Took my suspension out until it was replaced.
Does the compressor run at all? Have you tried running a feed to it? If the compressor has seized then it would instantly shut everything down. Was there any message on the dash? Special programs deactivated?
0 output from the height sensors? If you can reach one, disconnect it from the vehicle and see if the reading changes when you move the arm. The output should change. Unlikely that all four have failed at the same time.
Check the plugs at the back on the left hand side, just behind the rear wheel. Common problem of corrosion.
Otherwise without looking myself and probing bits it's hard the help but I'm sure someone with a greater knowledge of these will be along soon.2004 Disco 3 HSE TDV6
2015 Audi Q5 S Line plus
2008 Audi A4 Avant S Line Black Edition. Gone
2005 Chrysler Grand Voyger. Gone
1st Jul 2024 10:08 am
Alfadisco
Member Since: 19 Dec 2022
Location: Roma
Posts: 35
Hello Grumpydog,
Thanks for the reply.
After the suspensions went on the bump stops I got the “special programs deactivated” message and in the error codes I get that all other modules receive bad signals from the suspensions.
I will be able to lift it properly and run all checks only in a couple of weeks. Right now it’s sitting so low I cannot even shove the jack under it. I read somewhere this maybe because I have lift rods installed that cheat the car into being lower than it is so that the suspensions raise it more (I found that out only after buying it), but I could not make full sense of the statement as it seems counterintuitive.
For the same reason I cannot reach the sensors and play with them as you suggest.
For the moment I’m just relying on the diagnostics trying to make sense of them and taking the opportunity to learn a bit more about the car.
I thought the lack of signal was simply a consequence of the car sitting on the bump stops as the strength of the signal should regulate the riding height. So thanks for the suggestion.
2nd Jul 2024 8:21 am
Sidestick
Member Since: 22 Apr 2012
Location: Rome
Posts: 2313
Re: Suspensions, obviously
Alfadisco wrote:
For various reasons I have still not been able to lift the car and iti sitting too low to jack it up with the standard jack.
Find a way to lift up the car until almost 3 of the 4 height level sensor reads a minimum of 0,5 or 4,5 volt (depending on the sensors side) and with good probability the car will run again the compressor and slowly will rise the car to standard height.
Expect further DTC code as like "crosslink articulation" and the car on bump stops again until you run on
lift rods.
Every time sensors voltage drops below 0,5 or rise above 4,5 volt on at least of 2 sensors this car will sink on bump stops.
Suggestion: remove lift rods, make a new height calibration and keep live reading of the 4 sensor voltage while driving on rougher roads, if one or more readings start to flicker or loose digits (--) a new sensor is required followed by a new calibration.- Easy-Lift suspension module 4.0
- GoodWinch 9500 lb
- Full underbody protections
- Tree/Rock sidebars
- Prospeed roofrack & ladder
- Compressor guard
- Raised Air Intake
- Driving lights (2+4)
- 50 mm Waffle boards
- Altox Heater control
- Overland Rooftop Tent
- Rear seats entertainment
- Front & Rear camera
- GVIF
- Removable tow bar
- Cubby box fridge
- BFG KO2 265/65R17
- iidTool BT
2nd Jul 2024 4:50 pm
Alfadisco
Member Since: 19 Dec 2022
Location: Roma
Posts: 35
Hello Sidestick,
many thanks to you too for the advice.
That was the first thing I wanted to try as soon as I get the chance of raising it somehow.
I always suspected something was wrong with the lift rods since I was often getting unexpected and unexplainable (to me, at least) DSC activations but in the year and a half I’ve driven the car this is the first time something like that happens.
Bu then again, me not knowing much, seeing so many D3 drivers fitting lift rods I thought they didn’t pose any issue at all.
I guess my next purchase is a hydraulic jack low enough to fit under the boxy Tonga green Ferrari sitting in the driveway…
2nd Jul 2024 7:24 pm
von Horst
Member Since: 27 Dec 2022
Location: aneby
Posts: 127
And here you have it!! the ultimate design hickups of the suspension on the D3/D4, every little thing the smallest thingy that can go wrong and it screws up the suspension!! and its undrivable!
these are NOT my words but the words of one of the chief-engineers resposible for the entire drive-line on these cars!! well???
Anyway I love the D3, big, majestic! and lovely to drive! just spent 3 grand on replacing every bit of the suspension and now it drives like a dream! ( as long as it lasts).....look at todays Discos much smaller, with a cramped interior and with IMO uggly rounded chassis!
7th Jul 2024 9:27 am
Alfadisco
Member Since: 19 Dec 2022
Location: Roma
Posts: 35
Suspensions update…
…but no good news.
I finally managed to drive the car to the workshop. I did it with the Autel plugged in to monitor live values. Height sensors flickered a bit but always remaining below 0.5V.
At the workshop we jacked up the car. First from the front-left wheel, then rear-right one. Height sensors reacted issuing a much higher voltage but the compressor did not start.
We checked the feed to the compressor and it had no tension. All fuses and relays have been checked and are fully functional. We ran an external feed to the compressor and it started. Live values showed a 93C temperature reading for the compressor and, albeit working, it did not seem to do it properly. In particular, it seems to charge and shortly after discharge air in an alternating loop. We initially hoped it was simply filling up the tank but nothing happened. Pressure in the system was at around 3.4 bars.
Closer inspection of the height sensors revealed an embarrassing situation. All 4 vertical rods appear to have been tinkered with, and seem to be kept together by some wire. No idea why the previous owner did that. I attach two pics in case you are curious.
We will keep looking but any insights from more knowledgeable owners would be much appreciated and most useful.
Click image to enlarge
Click image to enlarge
23rd Jul 2024 9:52 pm
von Horst
Member Since: 27 Dec 2022
Location: aneby
Posts: 127
Yep I had all that nonsense and in the end I got fed up looking for faults so I changed all of it, new compressor, new tank! well, the lot!..if you got the money just do it!
Its a complete waste of time and frustrating just looking for faults and try to repair etc, etc!
24th Jul 2024 9:03 am
Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1805
The simple check for compressor problems is to remove the relay in the Battery box and with ign on jumper the two wide slots. the compressor should run. Check the 60/70 amp fuse near the relay. Known to blow.
24th Jul 2024 10:53 am
Alfadisco
Member Since: 19 Dec 2022
Location: Roma
Posts: 35
Thanks Globetrotter…
Disco is still sitting on bump stops.
We jumped the relay as suggested and indeed the compressor fired up and started working properly, although still no action from the air struts.
However, the weird thing is that when we plug in a new original relay there is no tension on the compressor line and the compressor obviously does not start. All 4 fuses have been checked again and are ok.
Diagnostics now returns all 4 codes on the "height sensor mechanism" (C1A72 C1A73, C1A74, C1A75), two new codes (C1A03, C1A04) that only refer to both "front height sensors", without any further information, and the DTC pair C1A27, C1A20.
Additionally, we get a number of UXXX DTCs (U0122, U0421, U0416) that I suspect reflect the fact that we have jacked up the car but suspensions did not work properly sending invalid data throughout the system.
Summing up,
1) live data shows that when the height changes because we jack up the car, the height sensors adjust their output so that they are responsive;
2) the compressor works if there is tension;
3) the suspension relay seems to cut the line to the compressor;
4) even if the compressor works, the air struts do not fill up even if the sensors register an insufficient height.
I have found posts about the C1A03, C1A04, etc, suggesting it might be height sensor wiring issues (broken cables, dirty connectors, etc). We will check but these came in only after days the car has been on bump stops.
The "mechanical" issues (C1A72 etc) were the first to be recorded but then again if height changes sensor readings change. Can we conclude there is no issue at the sensors or is it the case that if output voltage is too low (speaking of 0.xxx values) the system will record a fault? But then again, why when readings of some sensors are mechanically altered by jacking up the car nothing happens (tried this also with compressor externally fed).
I also found a post in the forum (https://www.disco3.co.uk/forum/c1a03-c1a72-faults-need-recalibrate-194186.html) saying that removing the F26 fuse is a workaround for the bump stop speed limit... haven't tried yet: does that mean it removes the bump stops issue (ie raises the suspension) or that it simply shuts down the dashboard warning to limit speed (because from what I remember from my drive back, it is only a warning and in principle the car can go faster and there is no engine power limitation)?
Apologies for the many - possibly confused and confusing questions . I am taking this experience as a training opportunity...
Many thanks for any insights.
26th Jul 2024 11:50 am
Sidestick
Member Since: 22 Apr 2012
Location: Rome
Posts: 2313
Re: Suspensions update…
Alfadisco wrote:
First from the front-left wheel, then rear-right one. Height sensors reacted issuing a much higher voltage but the compressor did not start.
From memory the car must be raised on all 4 corners at the same time to permit at least 3 of 4 plausible value from the height sensors - Easy-Lift suspension module 4.0
- GoodWinch 9500 lb
- Full underbody protections
- Tree/Rock sidebars
- Prospeed roofrack & ladder
- Compressor guard
- Raised Air Intake
- Driving lights (2+4)
- 50 mm Waffle boards
- Altox Heater control
- Overland Rooftop Tent
- Rear seats entertainment
- Front & Rear camera
- GVIF
- Removable tow bar
- Cubby box fridge
- BFG KO2 265/65R17
- iidTool BT
26th Jul 2024 4:21 pm
Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1805
You need to rethink the problem. If the compressor runs when jumpered then that part is okay. You need to look at what could stop the control system for not supplying a voltage. Depending on the age of the car (earlier than 2007), check the connectors behind the dirt shield on the passenger side front wheel. If 2007 or later the connectors to check are up by the left-hand headlight.
27th Jul 2024 12:35 am
ekwan
Member Since: 24 Apr 2016
Location: P Jaya
Posts: 34
Could be a duff relay.......correct?
Height sensor faults don't usually appear until the vehicle starts moving and the ECU thinks the height imbalance leads to a dangerous situation.
Even with a bad height sensor, you clear the DTC and the compressor would still run.
27th Jul 2024 1:28 am
Globetrotter448
Member Since: 21 Mar 2017
Location: Londonderry NSW
Posts: 1805
ekwan, you are correct about the duff relay.
27th Jul 2024 3:11 am
Alfadisco
Member Since: 19 Dec 2022
Location: Roma
Posts: 35
Ekwan, I think a duff (= bad, right?) can be excluded. We plugged in a brand new original relay and still no action.
Globetrotter, you are right on the approach. I was hoping to find in the forum some info on the routine checks the car runs in the key on/engine off position because that’s when it sank on the bump stops from normal height after a night parked. This sequence would give hints on what the ECU might have recorded to choose to put the car down.
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