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So when you look at the heights in SDS after starting the car back up, it shows that one corner is much higher than the others?
It would be interesting to see what happens if you put the car in park and let it idle after a drive, get out of the car and observe the ride height at that corner for a few minutes while the engine continues to run.
...when I park the car and turn it off, the backend raises for 20 seconds.
I believe the rear control valves have an internal leak which allows fluid to bypass them and enter the struts. This is not an issue while you are driving, since the ABC level control function counteracts the tendency by releasing fluid from the struts. But once you switch the ignition off level control in this case is terminating, and the residual hydraulic pressure in the system is sufficient to raise the rear end of the car. You can test this hypothesis as follows.
Begin with the ignition on and the engine off. Run Star Diagnosis and once DAS connects with the vehicle follow this menu path from the main screen: ..
Control units > Chassis > ABC > Control unit adaptations > Level calibration> Raise and lower the suspension struts at low speed ..
Read the instructions on the next screen and then proceed by pressing "F2". Start the engine. Since you are on a manual control screen, ABC automatic level control is disabled. Now observe the suspension height: It should not change; if it does, then you likely have identified a faulty valve block. If you determine this to be the case, then there are one or two other checks I would perform before drawing a final conclusion...
It would be interesting to see what happens if you put the car in park and let it idle after a drive, get out of the car and observe the ride height at that corner for a few minutes while the engine continues to run.
I believe the rear control valves have an internal leak which allows fluid to bypass them and enter the struts. This is not an issue while you are driving, since the ABC level control function counteracts the tendency by releasing fluid from the struts. But once you switch the ignition off level control in this case is terminating, and the residual hydraulic pressure in the system is sufficient to raise the rear end of the car. You can test this hypothesis as follows.
Begin with the ignition on and the engine off. Run Star Diagnosis and once DAS connects with the vehicle follow this menu path from the main screen: ..
Control units > Chassis > ABC > Control unit adaptations > Level calibration> Raise and lower the suspension struts at low speed ..
Read the instructions on the next screen and then proceed by pressing "F2". Start the engine. Since you are on a manual control screen, ABC automatic level control is disabled. Now observe the suspension height: It should not change; if it does, then you likely have identified a faulty valve block. If you determine this to be the case, then there are one or two other checks I would perform before drawing a final conclusion...
I will try this tomorrow and report back. Thanks in advance!
I believe the rear control valves have an internal leak which allows fluid to bypass them and enter the struts. This is not an issue while you are driving, since the ABC level control function counteracts the tendency by releasing fluid from the struts. But once you switch the ignition off level control in this case is terminating, and the residual hydraulic pressure in the system is sufficient to raise the rear end of the car. You can test this hypothesis as follows.
Begin with the ignition on and the engine off. Run Star Diagnosis and once DAS connects with the vehicle follow this menu path from the main screen: ..
Control units > Chassis > ABC > Control unit adaptations > Level calibration> Raise and lower the suspension struts at low speed ..
Read the instructions on the next screen and then proceed by pressing "F2". Start the engine. Since you are on a manual control screen, ABC automatic level control is disabled. Now observe the suspension height: It should not change; if it does, then you likely have identified a faulty valve block. If you determine this to be the case, then there are one or two other checks I would perform before drawing a final conclusion...
I tried this, and it did not change. I even left the car for hours and then went back and just started it (without star attached), and again, just starting does not adjust the height, it only adjusts when i either press the button or put it in gear (reverse or drive).
I would monitor the control currents to the four rear valves (two "control", two "lock") and see if they are nonzero during the 20-second interval that the rear rises. This post explains how to access the currents with Star Diagnosis.
I would monitor the control currents to the four rear valves (two "control", two "lock") and see if they are nonzero during the 20-second interval that the rear rises. This post explains how to access the currents with Star Diagnosis.
When you switch the engine off for a period of one minute the ABC level control function will lower the car if it rises in reaction to the car being unloaded. Items 80 and 81 from the actual values list are the currents for the left and right rear control valves, respectively. The currents are negative, and this suggests the ABC controller level control is trying to lower the car. You are not unloading the car, I presume, so a logical explanation is that the negative current is a counter-reaction to the rear rising due to a leaking valves. But under manual control (ABC level control disabled) and the engine running level did not change. That suggests the valves have no leaks. At this moment I can not reconcile this contradiction.
I suggest going back to the manual control screen as explained in post #5 and use the function keys to raise/lower one of the four corners of the vehicle. Verify that a positive current causes the vehicle to rise and a negative causes it to lower.
I suggest going back to the manual control screen as explained in post #5 and use the function keys to raise/lower one of the four corners of the vehicle. Verify that a positive current causes the vehicle to rise and a negative causes it to lower.
You have been very helpful so far, thank you for that.
I can 100% confirm this screen operates the vehicle exactly as its supposed to.
I did run a rodeo later this evening for good measure and it passed just fine.
I went ahead and ordered new fluid and a filter, so I can do a flush of the system, to see if that may help.
Have you run the height sensor calibration? I had a random issue with my car (never changed struts or worked on anything in the suspension) where it would fault and raise one rear corner high until the next drive cycle. I was able to re-calibrate the plunger travel sensors and it never did it again.
Have you run the height sensor calibration? I had a random issue with my car (never changed struts or worked on anything in the suspension) where it would fault and raise one rear corner high until the next drive cycle. I was able to re-calibrate the plunger travel sensors and it never did it again.
Very right, this is the first thing I do when I encounter non clear problems
Have you run the height sensor calibration? I had a random issue with my car (never changed struts or worked on anything in the suspension) where it would fault and raise one rear corner high until the next drive cycle. I was able to re-calibrate the plunger travel sensors and it never did it again.
I ran the level calibration, travel plunger sensor calibration and load adjustment. I noticed if I ran only the level calibration, then the ABC light came on asking me to run the other two items.
My next move would be to remove power from the ABC, start the engine, drive a few feet, stop the engine, and then observe how the rear rises compared to when ABC is powered. You remove power by pulling the 15-amp fuse from the main fuse box. If you are looking at the fuse box while standing at the front of the car it would be about the 8th from the top.
My next move would be to remove power from the ABC, start the engine, drive a few feet, stop the engine, and then observe how the rear rises compared to when ABC is powered. You remove power by pulling the 15-amp fuse from the main fuse box. If you are looking at the fuse box while standing at the front of the car it would be about the 8th from the top.
I tried first by removing the fuse and starting the car, this left the car with the rear sitting high. I replaced the fuse and started it, and it went to the correct height. Once i shut it off it raised again. I then turned on the car and removed the 15A fuse, and shut the car off and it keeps the correct height. I left the fuse out to see what happens overnight. Could this possibly mean a bad control module?
When the fuse is out I get this error, which seems typical for a module not receiving power:
I then turned on the car and removed the 15A fuse, and shut the car off and it keeps the correct height.
This makes two test results indicating that there is nothing wrong with your valve block, since when no current is applied to the valves the suspension does not move. That leaves the controller or one of its inputs as a cause and perhaps wiring as well, though I very much doubt it.
I asked you about control currents and I know you checked them, but I ask that you check them again from a different screen than before. Follow this path: .
Control unit groups > Chassis > ABC > Actuations > Control and locking valve or rear left suspension strut ,
On the control screen verify that pressing F5 causes a positive current to flow through the control valve and F7 a negative current. This is very important to have right, and that is why I have suggested checking it again. With either key the magnitude of the current should be 150 to 250 mA, as you can read from the screen.
This makes two test results indicating that there is nothing wrong with your valve block, since when no current is applied to the valves the suspension does not move. That leaves the controller or one of its inputs as a cause and perhaps wiring as well, though I very much doubt it.
I asked you about control currents and I know you checked them, but I ask that you check them again from a different screen than before. Follow this path: .
Control unit groups > Chassis > ABC > Actuations > Control and locking valve or rear left suspension strut ,
On the control screen verify that pressing F5 causes a positive current to flow through the control valve and F7 a negative current. This is very important to have right, and that is why I have suggested checking it again. With either key the magnitude of the current should be 150 to 250 mA, as you can read from the screen.
This morning I went outside and the car was exactly how I left it. Perfectly level, and hasn't skipped a beat.
I tried what you said above. I firstly replaced the 15A fuse in spot 13. I turned it on, activated the system by pressing F3, then moved it via F5 & F7 and the numbers were within spec. Each corner moved as it should -196mA to +196mA depending if I am moving it up or down. Pressure roamed between 177-189bar. No fault codes were present in the system.
When I shut my car off, it started raising the rear again. Where does this point me? Corrupted ABC Module?
Hey guys. I am having a suspension related issue with my sl600. Pic below:
Everything seems fine with the ABC; no warning lights or anything, however when I park the car and turn it off, the backend raises for 20 seconds.
Once I start my car and drive, it levels off. The button is at the lowest setting, and I have already replaced two struts.
Rodeo shows no faults and holds pressure fine. SDS shows no faults. Im really lost here.
Any ideas?
maybe this helps Keep It Clean
Even the smallest piece of debris or dirt can cause the system to malfunction. The most common debris in the system is usually small pieces of rubber from the solenoid valves and accumulators. These seals can degrade due to age and the extreme pressure generated by the system. The debris will stick to the plunger or seat of the valves that control the suspension.
This obstruction will cause the suspension to raise or lower depending on whether the inlet or outlet valve is leaking internally. When this happens, the suspension will raise or lower and then be corrected by the system to return it to a normal height. This behavior might take seconds or minutes, depending on the size of the internal leak.
06-09-2020, 07:24 PM
