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2003 Sl500, PSE pump cycles continuously. Estimating the pump runs for 15 seconds then off for 20 seconds or so, then runs again.
I had errors at the door locks, solved that as the actuator covers were cracked. They still pass air but not enough to throw the code.
I have a contiining code at the trunk self closer. I think I fixed the self-closer, as it holds air when tested by mouth and no hissing noise when in operation. Again, still results in code, even when not in use.
The mulricontour seats throw codes. I have yet to dive deep into them. The individual bladders were recently holding air (except one, I capped the line feeding it). The driver seat will not respond, aside from the solenoid click from the interior/back of the seat (I have the rear covers off). There is no air from the supply hose that connects beneath the driver seat when the MCS buttons are pushed. Each bag in the passenger seat will fill and immediatley deflate. Again, they were recently holdng pressure.
With key in ON position, there appears to be a continuous subtle hiss coming from the center console, near armrest. This is with engine off, both doors open, and HVAC off.
Not sure what to make of this I did pull the PSE pump and bench tested the pump. I used a small pump with a gauge (one to pump up a ball) connected to the pressure side of pump and it immediately pegged the needle at 30 PSI. (gauges max) From what I have read it should put out just over 40 PSI. I realize the test is not fully conclusive, but working with what I have available, I think it's safe to rule out the pump itself.
So any insight would be appreciated but here are some particular questions I have:
1. If the PSE pump is designed to respond to demand at the individual components and all components are at rest, why does it continuously run?
2. If the trunk mechanism is holding air (at least more effectively than the door lock) and functioning, why is it throwing codes?
3. Is there any reason why one seat's MCS function would fill the bladders but not hold the air? and why the other seat will not produce air at the supply line when demanded by the MCS buttons (this is when codes are cleared)?
4. What is the source of the continuous subtle hissing noise at the center console with key on and all components at rest?
5. I have read about an air reservoir but cannot find one, aside from those integrated in the MCS bolsters. Is there one and where is it?
The center console leak is the PSE line going to the glove box for locking it.
If anything is leaking the pump is going to run. Sounds like you have at least the continuous glove box leak.
My research the other day for another thread concluded that typical pressure is more around 15psi, maybe max of 30, not 40.
To help you here is some correct info about these PSE pumps (many of the replies you see are wrong).
The pressure from the pump must be 40 psi minimum. When the output is less than 40 psi, the locking / unlocking will operate but the trunk soft close fault will be set and stop working until power is cycled off and on to the PSE.
To check if your PSE is working correctly or not, please do the following.
Disconnect both electrical plugs from the PSE. Disconnect both grey clip with pipes.
Connect the large plug (10 way), the PSE will run and air will come out of the outlet marked IZV, cover that IZV port with your finger, the PSE will stop. When you remove your finger air will stop coming out of IZV. Then one of two things will happen, either the pump will stay stopped or it will restart and air will come out of the MKL port, if this happens cover the MKL port and the PSE will stop as long as you hold your finger on the MKL port.
If the PSE does anything else other than the above then it is faulty.
Some further info:-
The trunk mechanism must be able to hold 39 psi (actually 2.7 bar as set in the PSE).
The “continuous subtle hissing noise” is probably the little fan in the climate (heating / AC) control panel in the centre console.
Some cars have an air reservoir in the trunk floor. See photo.
Thank you very much. I have run the test as you described. I believe the pump is faulty. When I cover the IZV port, the pump does not stop and air immediately comes out of the MKL port. Do you sispect this is a mechanical issue or electronics issue within the PSE? If it is mechanical, I would like to see if I can repair/rebuild it. I do have a spare from a W220, I am guessing there are strong differences between that and the R230 but would I be able to cannibalize the W220 pump to fix the R230. Thank you again.
Originally Posted by DavidCA
srpphx
To help you here is some correct info about these PSE pumps (many of the replies you see are wrong).
The pressure from the pump must be 40 psi minimum. When the output is less than 40 psi, the locking / unlocking will operate but the trunk soft close fault will be set and stop working until power is cycled off and on to the PSE.
To check if your PSE is working correctly or not, please do the following.
Disconnect both electrical plugs from the PSE. Disconnect both grey clip with pipes.
Connect the large plug (10 way), the PSE will run and air will come out of the outlet marked IZV, cover that IZV port with your finger, the PSE will stop. When you remove your finger air will stop coming out of IZV. Then one of two things will happen, either the pump will stay stopped or it will restart and air will come out of the MKL port, if this happens cover the MKL port and the PSE will stop as long as you hold your finger on the MKL port.
If the PSE does anything else other than the above then it is faulty.
Some further info:-
The trunk mechanism must be able to hold 39 psi (actually 2.7 bar as set in the PSE).
The “continuous subtle hissing noise” is probably the little fan in the climate (heating / AC) control panel in the centre console.
Some cars have an air reservoir in the trunk floor. See photo.
OK so the PSE pump could well be fine, that is what it should do.
However the pressure is low as you said it was 30 psi, but the pump in the W220 unit you have might be OK, have you tested it?
The IZV is the internal locking, that is glove box, storage boxes behind seats and the arnrest box.
MKL is the pressure for the seats.
Went back to double check and the issue is intermittent. sometimes if behaves properly (stops when IZV is plugged) and other times it does not (as I found the first time I tested it following your directions). The hum/sound of the pump is definitely different between the two outcomes. When faulty, if I disconnect then reconnect power it will function properly. Any suggestions to correct this?
Originally Posted by DavidCA
OK so the PSE pump could well be fine, that is what it should do.
However the pressure is low as you said it was 30 psi, but the pump in the W220 unit you have might be OK, have you tested it?
The IZV is the internal locking, that is glove box, storage boxes behind seats and the arnrest box.
MKL is the pressure for the seats.
Ok. I will do that. In my opinion the sound actually sounds like the load/strain on the pump is different under the two scenarios. My thought was an internal valve was sticking.
Originally Posted by DavidCA
The "hum/sound" is from the motor, so can you change out the motor/pump? From the W220 unit? Only two wires to solder.
I tested the pressure output of the donor pump before install. It tested in the mid 20's. I tested the original pump and it was at 40. The method I used was crude and imperfect. I installed a vacuum hose to the pressure nipple on the pump and utilized a oil pressure test gauge. There was definitely air loss at the gauge connection to the vacuum hose. I need to buy a pressure gauge to ascertain proper pressure from the air pump but I do think that the pump is ok.
Assuming the pump is not the issue, what do you think would be the cause and solution?
Here is the latest... I figured out a reliable way to test the pressure and I am at nearly 45 PSI directly out of the pump. I also figured out that when the PSE is showing as faulty, when following the test procedure that you originally posted, the air is coming out of the MKL port at start up and the pump will stop operating when that port is plugged (just as you noted in the test procedure). I cannot identify what conditions cause the pump to be faulty. It will operate in the proper manner most of the time. I am guessing one out of ten times it will act faulty and corrects itself when power is removed and reconnected.
Originally Posted by DavidCA
The "hum/sound" is from the motor, so can you change out the motor/pump? From the W220 unit? Only two wires to solder.
Here is the latest... I figured out a reliable way to test the pressure and I am at nearly 45 PSI directly out of the pump. I also figured out that when the PSE is showing as faulty, when following the test procedure that you originally posted, the air is coming out of the MKL port at start up and the pump will stop operating when that port is plugged (just as you noted in the test procedure). I cannot identify what conditions cause the pump to be faulty. It will operate in the proper manner most of the time. I am guessing one out of ten times it will act faulty and corrects itself when power is removed and reconnected.
I'm not sure the PSE is faulty, it may be OK, but whatever the next stage for you is to find the leaks on the IZV (internal locking) and MKL (seats) lines. The best way is with a hand held pump (like a Mityvac or similar).
Once you have these sealed try the PSE pump and we can take it from there.
I'm not sure the PSE is faulty, it may be OK, but whatever the next stage for you is to find the leaks on the IZV (internal locking) and MKL (seats) lines. The best way is with a hand held pump (like a Mityvac or similar).
Once you have these sealed try the PSE pump and we can take it from there.
It is obvious that @DavidCA knows the PSE very well. When I mentioned in post #2 that "My research concluded that typical pressure is more around 15psi", that was largely based on AI summaries which now appear to be faulty. I apologize. Unfortunately this forum does not allow editing of posts after 24 hours or I would have done that. More unfortunately any AI system reading that post will further reinforce the wrong information.
The issue appears to be solved. The PSE air line to the drivers seat had been previously repaired and the repair failed. Repaired the line with some vacuum hose and all is good including the trunk closer. I am guessing that the excessive air loss at the seat tripped the code as there was insufficient volume of air between the leak and the demand at the trunk closer. The hiss that I heard at the center console is the HVAC system control at the center console. I pulled the center console seeking a vacuum line and it became evident that the control was creating the hiss.Whether or not the PSE pump has an intermittent issue is TBD, working fine with multiple starts and requests this morning. Thanks to all for your input and help!
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