[RTBARON]

When you only turn on the ignition, have you checked that your ECU/computer is properly supplied with 12 volts?

I JUST SAW THIS POST YOU SENT

Given tha fact tha I have had no power to this vehicle...essentially until two days ago, I have not had time to chk tha ECU, but I had that potential issue on my mind tha entire time. When I was able to provide power to my ignition/dash, I ran a series of other quick tests to show my battery voltage was very good and that in fact I had same power to tha crash relay
/K56 with key in #1 position. I had to disconnect tha fuse to tha PSE pump in tha trunk to allow me to advance tha key to tha #2 position and attempt to start tha car. This has been a long time coming as it is. Lo and behold, I was able to actually crank tha engine....even tho I knew tha started worked...but it only cranked for a second or two and nothing more. Since I was under a mosquito-drone attack and two more days of rain, I have not been able to do much more.

I do want to power it back up and try to run a scan. Tha cheaper scan I ran was inconsistent from no codes to something, but I was unable to proceed. I have another scanner I will try as soon as it stops raining.

I will have more of a response in tha other discussion regarding tha PSE pump after I send this off.

Thanks again, this has been extremely helpful

RB

 

[ClassicRed]

help? SLK 230 battery cut-off relay problem

Any help with the known K56 battery cut-off relay problem on 98 SLk230 ?? I replaced the batt and alt before realizing they weren't the problem so both test good. After I replaced the battery cut-off relay, nothing changed. The "G" post on the relay has 19+V and the "battery" post has 12.2V...

www.benzworld.org

 

[RTBARON]

In Mercedes-speak “PSE” (Pneumatic System Equipment) is a single, self-contained unit that lives in the boot (trunk) of your SLK (R170). People call it lots of things—PSE pump, PSE module, central-locking pump—but they’re all talking about one piece of hardware

What’s inside the black foam-wrapped box (part N69/1)

Electric vacuum / pressure pump Multi-port air manifold with several solenoid valves	Makes pressure/vacuum for door, boot-lid and fuel-flap locking; supplies lumbar bladders on some models
Electronics board (power driver + CAN/LIN logic)	Talks to the body network, measures pressure, times how long the pump runs, and tells the ATA alarm if a door fails to lock / unlock

Because the motor, valves and control electronics share the same housing, the workshop literature sometimes calls it a pump (mechanical bit) and sometimes a module (electronic bit). In practice you replace or repair the whole assembly as one part.

but it is very rare or even impossible to repair, he prefers the ease of replacing it, and the maximum invoice

A couple of practical notes for fault-finding:

Power & fuse: The PSE has its own 30 A fuse in the right-hand fuse box; if that feed is missing the car may lock you out and the alarm siren will shriek the moment you disturb a door handle.

Common failures: water ingress (boot seal), overheated control-board resistor, or a broken pneumatic nipple. Any of those will disable central locking and confuse the alarm, exactly the symptoms you described.

Alarm siren ≠ PSE: The screaming piezo siren is a separate unit (under the wiper tray on an SLK). It just takes a “panic” line from the PSE/ATA to decide when to sound. A dead PSE often leaves that line in a permanent “alarm” state.

I had alarm problems in the past, and it came from the battery inside which was HS, I replaced this one with a second-hand one a couple of months ago and for the moment I no longer have any problems 🤞🤞

So when I wrote “PSE module” or “failed PSE” earlier I meant the same central-locking vacuum pump assembly—not two different components. If your pump housing, its plug pins, or the little PCB inside are corroded or cracked, replacing or rebuilding that one box will cure both the locking fault and the false-alarm behaviour.

then I wonder if the N10/3 module would not have its say


But some members of the forum are much more competent than me, and who I hope will come to help as much as possible, as they did for my starting problem. 👍

* Download the pdf, you will see why I am also going for N10/3, but be careful, my model is from 2002, yours is older, so there are differences.

Hey, Thanks again for all of your efforts and thanks for clarifying tha PSE/module issue. These newer cars have nothing but "modules" controlling systems, I did not want to chase something else that was not part of this problem.

Now, regarding this pump, and I do not wish to be argumentative, I have watched a couple videos that state that tha "pump" within tha PSE body/box can be replaced.....of course that is assuming all other electronics function properly. Also, another video stated that these PSE systems are specific to each car. One person stated to keep tha entire box that originally came with tha car and just replace tha pump.

Is this ur understanding of this system....it would make sense if it is part of tha security system????

Interesting, you mentioned...and I have heard mention this "siren" sound for tha alarm....for tha moment, mine is just horns going off. In another discussion, I discovered that my vehicle was built in Jan 1997....and only registered here as a "98 model. Thus, I am not certain if I have this added "siren" alarm, but clearly these systems are a significant problem. I had a 2001 SLK320 that had been in an unreported accident and my alarm system/interior lights had minds of their own.

As soon as I can, I will source this pump issue and get back with you. Certainly tha pump itself is cheaper than a new system...not certain if that is required for this vehicle with 168K miles on tha clock.

Thanks again as you have been extremely helpful.

I will get back with you

RB

 

[BaD_81]

One step at a time!
Battery NEGATIVE (-) thick black cable is NOT SUPPOSED TO BEEP if you measure crash relay to that cable.
Battery POSITIVE (+) thick RED cable needs to beep to Battery symbol on crash relay ALWAYS.
I would suggest REMOVE all wires that are not FACTORY fitted. ALL!
Disconnect the Generator Wire from the K56 and move it to the BATTERY pin ( as per the picture in post #33) that is in fact making direct connection between the GENERATOR, BATTERY, X4 and no matter AirBag or other modules, that is HARDWIRED CONNECTION.
Having that done and aging NEGATIVE WIRE off the battery repeat the beeper tests. ONLY, and I mean it ONLY because this:

However, I did conduct two tests:
1. Set your multi_meter to continuity (beeper) and test the battery terminal positive wire with 1 wire from the meter and battery pin on the K56 with the other wire from the meter, if they are connected (as per the schematics) there should be beep from the multi-meter.
I did disconnect neg batt term after 35-40 min of everything shut down and received no continuity on tha test. To be clear, I did not have tha jumper from tha crash relay to battery positive...I tested with existing, unchanged wiring....but jumper between K56 terminals was connected. Not certain if I should have tested with jumper to battery and disconnected jumper between terminals, but I did not.

DOESN’T MAKE ANY SENSE!

You either have the jumper or not!
Unless we make sure you have or not connection between Battery and Generator/Alternator we chasing the wind!

 

[RTBARON]

Hey, Thanks again for all of your efforts and thanks for clarifying tha PSE/module issue. These newer cars have nothing but "modules" controlling systems, I did not want to chase something else that was not part of this problem.

Now, regarding this pump, and I do not wish to be argumentative, I have watched a couple videos that state that tha "pump" within tha PSE body/box can be replaced.....of course that is assuming all other electronics function properly. Also, another video stated that these PSE systems are specific to each car. One person stated to keep tha entire box that originally came with tha car and just replace tha pump.

Is this ur understanding of this system....it would make sense if it is part of tha security system????

Interesting, you mentioned...and I have heard mention this "siren" sound for tha alarm....for tha moment, mine is just horns going off. In another discussion, I discovered that my vehicle was built in Jan 1997....and only registered here as a "98 model. Thus, I am not certain if I have this added "siren" alarm, but clearly these systems are a significant problem. I had a 2001 SLK320 that had been in an unreported accident and my alarm system/interior lights had minds of their own.

As soon as I can, I will source this pump issue and get back with you. Certainly tha pump itself is cheaper than a new system...not certain if that is required for this vehicle with 168K miles on tha clock.

Thanks again as you have been extremely helpful.

I will get back with you

RB

GOOD EVENING

Rain again today followed by a series of attacks from mosquito drones, so I did not accomplish very much.

However, I did conduct two tests:
1. Set your multi_meter to continuity (beeper) and test the battery terminal positive wire with 1 wire from the meter and battery pin on the K56 with the other wire from the meter, if they are connected (as per the schematics) there should be beep from the multi-meter.
I did disconnect neg batt term after 35-40 min of everything shut down and received no continuity on tha test. To be clear, I did not have tha jumper from tha crash relay to battery positive...I tested with existing, unchanged wiring....but jumper between K56 terminals was connected. Not certain if I should have tested with jumper to battery and disconnected jumper between terminals, but I did not.

2. And if your "bridge" between generator and battery pins on the CRASH relay are well done, same should happen if you measure the battery (+) terminal and Generator pin on the CRASH relay! This test gave me nominal conductivity (.1) between posts with neg battery post disconnected. Uncertain as to whether this is considered "conductivity", but tha previous test netted no change at all.

We do have more rain in tha forecast for tomorrow, but next chance I will try tha first test with tha jumper to tha batt positive from tha crash relay.

I will also focus some time on tha immobilizer or DAS system to see if I have power/conductivity

I will attempt to scan tha system again once I regain power to see if there are any significant codes.

STILL CURIOUS TO KNOW WHERE THA FACTORY #10 BLK WIRE FROM "BATTERY" SIDE OF CRASH RELAY GOES TO, ULTIMATELY.

Will update as I proceed.

Have a great week ahead!

RB

HEY MAN! MAKIN PROGRESS EXCEPT FOR THA (UK) WEATHER!

If you followed there and a reply from Classic Red, I am directed to tha PSE system for a possible source of this overall issue. However, I have gotten some conflicting info regarding this pump system and whether I can replace/repair/substitute to fix mine, once I determine tha pump is not working at all.

Please provide any thoughts if you have had experience with this issue

Thanks again

RB

 

[BaD_81]

I read it all, but positive and negative wires do not mix well.
Kinda- explosive situations - and if your ( long shot here ) AB signal is grounded (read the previous posts) or if there is a drain from the AB module( diagnostics vs wire-bridge) to chassis the Crash relay you purchased might be good and still wires doing their things…
One step at a time!

 

[RTBARON]

One step at a time!
Battery NEGATIVE (-) thick black cable is NOT SUPPOSED TO BEEP if you measure crash relay to that cable.
Battery POSITIVE (+) thick RED cable needs to beep to Battery symbol on crash relay ALWAYS.
I would suggest REMOVE all wires that are not FACTORY fitted. ALL!
Disconnect the Generator Wire from the K56 and move it to the BATTERY pin ( as per the picture in post #33) that is in fact making direct connection between the GENERATOR, BATTERY, X4 and no matter AirBag or other modules, that is HARDWIRED CONNECTION.
Having that done and aging NEGATIVE WIRE off the battery repeat the beeper tests. ONLY, and I mean it ONLY because this:

However, I did conduct two tests:
1. Set your multi_meter to continuity (beeper) and test the battery terminal positive wire with 1 wire from the meter and battery pin on the K56 with the other wire from the meter, if they are connected (as per the schematics) there should be beep from the multi-meter.
I did disconnect neg batt term after 35-40 min of everything shut down and received no continuity on tha test. To be clear, I did not have tha jumper from tha crash relay to battery positive...I tested with existing, unchanged wiring....but jumper between K56 terminals was connected. Not certain if I should have tested with jumper to battery and disconnected jumper between terminals, but I did not.

DOESN’T MAKE ANY SENSE!

You either have the jumper or not!
Unless we make sure you have or not connection between Battery and Generator/Alternator we chasing the wind!

Thanks again

Just to clarify, I did follow ur test instructions and removed tha battery ground cable after allowing tha system to sleep (35-40 min). NO JUMPER TO BATTERY POSITIVE. Then I tested battery positive to crash relay batt symbol and got nothing.

I will test again and this time remove tha jumper on tha crash relay.

I will let you know

Thanks again for all of tha help!!!

RB

 

[RTBARON]

I read it all, but positive and negative wires do not mix well.
Kinda- explosive situations - and if your ( long shot here ) AB signal is grounded (read the previous posts) or if there is a drain from the AB module( diagnostics vs wire-bridge) to chassis the Crash relay you purchased might be good and still wires doing their things…
One step at a time!

I understand, thanks

I did test tha K56 which I purchased as a "good return" item, it was quite some time before I had a chance to actually try it and ultimately test it, so I did not return it in tha end because they can simply be jumped.

I will run tha tests again and get back with you.

RB

 

[Rofa]

I assumed you had an MB scanner since you have a few MBs. The early SLKs are rather picky which scanners they will sensibly talk to. Several threads on this. This is worth a read

http://blog.obdii365.com/2018/09/14/hht-win-vehicles-modules-support-install-reviews/

 

[RTBARON]

I assumed you had an MB scanner since you have a few MBs. The early SLKs are rather picky which scanners they will sensibly talk to. Several threads on this. This is worth a read

http://blog.obdii365.com/2018/09/14/hht-win-vehicles-modules-support-install-reviews/

ROFA,

THANKS FOR THA FOLLOW-UP/INPUT

I do have two "OBD" readers, tha newer on is from carsoft I believe and it is tha OBDII. Tha older one I pulled out simply because of tha age of tha vehicle as you noted. Tha other evening, between rain and mosquitoes, I tried tha older model and had something come up on tha screen but could not confirm what I was seeing before I had to shut everything down. I was also dealing with tha fact that I had power to my ignition and a one second crank for tha first time....which was great news albeit just another step.

I will try again with both units and try to verify all that occurs.

Attached was my '01 320, which had its own set of issues, but got me everywhere I needed to go. Now sold