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11-20-2023, 09:38 PM | #1 |
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G12 750i Ride height error
Hello guys, I'm having some issues with my G12 with the self leveling suspension. I noticed that my corners of the car will randomly sag sometimes overnight after parked and I'm not sure why. When I drive the car in comfort or sport, I don't get any chassis malfunction codes and the car stays level.
If I try to put the car in the highest setting using the button to raise it, the rear starts inflating, however, the front doesn't start inflating and I get a chassis error code (482974 - VDP: Vehicle level - not adjustable). I also hear the compressor louder than before. To me it sounds like a compressor/valve block issue? Steps I've done to troubleshoot issue: *Deleted the chassis fault and registered the correct ride height via ISTA *Installed a new AUX battery and registered it. |
11-21-2023, 10:53 AM | #2 |
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The fact that suspension is sagging tells me that there is a leak in the system. This leak could be in air struts, air lines or compressor and valve assembly.
Why you are hearing compressor louder than before is because it is working hard - too hard. Normally, you should never hear compressor run, because it rarely ever runs, and if it does, it's pretty silent. All the needed air is stored in pressure accumulation tanks. When you develop a leak somewhere in the system then compressor has to run a lot more than it was ever designed to. This will destroy the compressor in very short time. Usually it gets audible before it dies, so I bet yours is on its last legs. Good news is that as I understand from your other post regarding HSR battery, you are still under factory warranty. This should cover all components of air ride. There is also extended milage goodwill warranty for air struts. |
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Recon3D17.00 |
11-21-2023, 11:25 AM | #3 |
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What year is it? If its a 17' plus, there is a service bulletin that might still cover your suspension. I have a 16' and was able to get two of the struts replaced under warranty. That ended in October for me.
For me that wasn't all I needed. I also replaced the compressor and two air lines through a private shop since the warranty only covers the struts. |
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11-21-2023, 11:51 AM | #4 | |
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I found the Service Bulletin (SIB 01 05 22) on the extended warranty for the air struts (My car is a 2016 with 67k miles). If you have any more info on this I would greatly appreciate it!! Edit: Should I start troubleshooting this issue with an air compressor replacement first or my taking it to the dealer in hopes that they replace the faulty struts? Last edited by Recon3D; 11-21-2023 at 12:08 PM.. |
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11-21-2023, 11:59 AM | #5 | |
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Will the dealer test the struts for leaks or how exactly will they determine if the struts need replacing if my car randomly sags? |
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11-21-2023, 02:53 PM | #6 |
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Take it to a dealer and let them take a look at it. They must have some specific procedures to determine faults in air ride system. They mostly get the diagnosis and repairs right, as far as I have gathered.
Do not replace the compressor before you haven't figured out what exactly is the issue. Doing that might very quickly kill the new compressor, as it has to run well past its design specs to accommodate for a leak elsewhere in system. As you can hear air noises coming from strut areas, then good possibility is that there is a leak in one or more. If that is the case, then I think BMW will have you covered. If you have to go out on a pocket for a new compressor after that, then so be it. At least you have new struts on the house and the compressor you will have to buy wont blow up after couple hundred miles. Be aware that I have also seen air ride do funny things when VDP module is defective. At any rate, it needs to be properly diagnosed before anything is done. |
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Recon3D17.00 |
11-22-2023, 07:20 AM | #7 | |
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Drives: 2018 BMW 740i Xdrive M Sport
Join Date: Jan 2020
Location: Fishers, IN
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Glad you found the bulletin, get it to the dealer service shop ASAP. You are covered. Warranty will not cover a blown compressor...and that could possibly happen if you continue to drive the car in this condition. |
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11-29-2023, 11:41 AM | #8 | |
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Will update further if issue is fully fixed after I get the car back. The part that doesn't quite make sense is why one of the days when I went outside, the entire left side of the car was sagging (including the rear left). |
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11-29-2023, 06:03 PM | #9 | |
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Oh and glad to hear that BMW has you covered for the repairs. |
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12-21-2023, 09:08 PM | #10 |
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After getting the car back and driving it for a bit, it does indeed seem that the issue was fixed due to the air spring replacement.
Something interesting that I noticed when I looked over the paperwork is that the part numbers for the front left/right air springs are not what I expected. I tried to cross reference the parts, however, I don't see them listed on any bmw parts website. Searching Realoem also doesn't result in anything. The paperwork lists the following parts that were replaced: Air Spring Front left: #37105A4A615 Air Spring Front Right: #37105A4A666 While searching online for these parts, these parts seem to be significantly cheaper than the entire strut replacement that I saw on various websites. So I could only wonder if this was a repair/service kit for the airbag portion? Nonetheless the car drives as it should |
12-21-2023, 11:03 PM | #11 |
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Yes, these should be entire air spring portion of the strut. They now make repair kits like that. What they do is take damper out of the old air strut and install it into new one, as hydraulic dampers themselves are rarely the issue on lower milage cars, and those EDC dampers aint cheap.
Thanks for reporting back with the codes. These might come very handy for someone who has to do this job out of the pocket. |
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01-14-2024, 07:00 PM | #12 |
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I’m also having the same issue but worser, my front passenger side is sagging when the car is level but the suspension has become unlevel, this happens 3 times a week and it usually goes away after a bit of driving but it hasn’t gone away today. Here are the images
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01-14-2024, 10:05 PM | #13 | |
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Below is an excerpt from TIS: Notes on vehicle tilt (2-axle air suspension) System-related causes (no faults)
The air in the spring struts is warmed by the engine heat and damper work and expands. This raises the vehicle. During the journey, ride height changes due to temperature changes in the air suspension struts are corrected. When the vehicle is stationary and switched off, these temperature effects may lead to ride height changes and inclinations that are not corrected. When the engine is hot, an after-heating effect occurs after the vehicle is stopped that causes the vehicle to first be raised slightly within the first hour and be lowered again during the cooling-down period. In extreme cases, the temperature effect on the front axle may cause the vehicle to be lowered up to 50 mm. After the vehicle is parked, the self-levelling suspension performs up to six control procedures within the first 48 h during which, depending on the system availability, an attempt is made to reduce possible inclinations by raising or lowering the vehicle to a horizontal level. The self-levelling suspension may hereby lower the vehicle to up to 40 mm below the normal level. For technical reasons, inclinations in vehicles that have been parked for lengthy periods cannot be avoided in air suspension systems. Workshops are not able to check the control functions in parked vehicles due to the system complexity. Checking the ride height adjustment
Possible causes of mechanical faults
Larger leaks can be found using the following procedure. The determination for small leaks is significantly more extensive and lengthy to exclude effects from temperature changes and axle strain. According to the specifications, the leak may reach up to 2 mm per day (constant temperature, vehicle is parked on skid-proof plates -> no axle strain).
Last edited by M_Bimmer; 01-14-2024 at 10:55 PM.. |
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HamsaAden0.00 |
01-14-2024, 10:12 PM | #14 |
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Thanks for the reply, my car has not been on a lift at all. This suspension issue started one rainy day and the warning that popped on the screen was “Chassis Function Limited” but the uneven suspension problem seems to only happen when it snows and when it’s very cold outside.
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