figuring out solenoid functions in abc valve block
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Junior Member
Joined: Dec 2012
Posts: 60
Likes: 3
From: Iowa
04 CL55 AMG
figuring out solenoid functions in abc valve block
not sure anyone would have an answer for this but i am trying to figure out the solenoid functions in abc valve block .
there are four per block two smaller and two larger and my thought is the the smaller ones control the suspension on the low setting and the larger ones control the high setting when you raise the car . that is what i am trying to figure out what ones do what ? four of them so obviously one for right and one for left high and low settings .
my issue is the car still wants to lower on the right side after a day when engine is off , and when engine is running and car not rolling it will slowly rise until i start rolling then it will lower to proper height and stay there as long as I'm moving .
on the raised setting it holds great for days setting and will not drop at all .
i know it's not the o-rings i have pulled it back apart and they are fine so it is internal in one of the solenoids i just need to figure out what ones control the suspension on the low setting .
my only option may be to pull them out again and remove the plungers from the solenoids and check for debris that may be keeping them from closing all the way . the plungers on the small ones were very easy to pull out , but the larger ones i was not sure how to remove them ? and did not want to damage anything .
on the plunger in the small solenoid there is a small square type o-ring that could let fluid seep by ? and if the smaller ones control the car at the low setting then that would be the problem .
wish you could just buy the solenoids without buying the whole block !
Dave
there are four per block two smaller and two larger and my thought is the the smaller ones control the suspension on the low setting and the larger ones control the high setting when you raise the car . that is what i am trying to figure out what ones do what ? four of them so obviously one for right and one for left high and low settings .
my issue is the car still wants to lower on the right side after a day when engine is off , and when engine is running and car not rolling it will slowly rise until i start rolling then it will lower to proper height and stay there as long as I'm moving .
on the raised setting it holds great for days setting and will not drop at all .
i know it's not the o-rings i have pulled it back apart and they are fine so it is internal in one of the solenoids i just need to figure out what ones control the suspension on the low setting .
my only option may be to pull them out again and remove the plungers from the solenoids and check for debris that may be keeping them from closing all the way . the plungers on the small ones were very easy to pull out , but the larger ones i was not sure how to remove them ? and did not want to damage anything .
on the plunger in the small solenoid there is a small square type o-ring that could let fluid seep by ? and if the smaller ones control the car at the low setting then that would be the problem .
wish you could just buy the solenoids without buying the whole block !
Dave
Junior Member
Joined: May 2008
Posts: 33
Likes: 4
2005-CL55, 2006-R350
I don't have a flow circuit for the CL hydraulic system... But if I had to guess based on one-way hydraulic actuators I use:
There are 4 solenoids, 4 hoses and 4 wires
Hose #1: High pressure supply
Hose #2: Low pressure return
Hose #3,4: Hydraulic lines to each shock
The smaller solenoids should connect the shock to the high pressure supply (one each)
The larger solenoids should connect the shock to the low pressure return (one each)
To raise the car, the small solenoid opens momentarially. To lower the car the large one opens momentarially. Pump pressure causes the flow for the raise function, shock pressure (from the weight of the car) cause flow for the lower function. I wouldn't think either stay open for very long. A leak on any valve would sag the car when the motor is off, unless there were check valves in the valve block... then it would only be caused by the larger valves/solenoids.
The ABC system doesn't have a low, middle and high position per-se... those are just setpoints that the system tries to maintain. Actually, the system is constantly raising and lowering the vehicle based on load, acceleration and cornering. The control unit senses the wheel height using the sensor (looks like a potentiometer or servo) and makes up/down adjustments to keep the setpoint you set via the dash buttons.
All purely hypothetical (since I don't have a diagram), it could just run off of pixie dust.
There are 4 solenoids, 4 hoses and 4 wires
Hose #1: High pressure supply
Hose #2: Low pressure return
Hose #3,4: Hydraulic lines to each shock
The smaller solenoids should connect the shock to the high pressure supply (one each)
The larger solenoids should connect the shock to the low pressure return (one each)
To raise the car, the small solenoid opens momentarially. To lower the car the large one opens momentarially. Pump pressure causes the flow for the raise function, shock pressure (from the weight of the car) cause flow for the lower function. I wouldn't think either stay open for very long. A leak on any valve would sag the car when the motor is off, unless there were check valves in the valve block... then it would only be caused by the larger valves/solenoids.
The ABC system doesn't have a low, middle and high position per-se... those are just setpoints that the system tries to maintain. Actually, the system is constantly raising and lowering the vehicle based on load, acceleration and cornering. The control unit senses the wheel height using the sensor (looks like a potentiometer or servo) and makes up/down adjustments to keep the setpoint you set via the dash buttons.
All purely hypothetical (since I don't have a diagram), it could just run off of pixie dust.
