SLK Problems

My SLK 230 Kompressor seems to have stopped working - well theres no boost. Im told that the Engine Control module needs to be replaced. It costs over 4 thousand NZ$!!!!
It this a common fault and is there somewhere that repairs the module.
I dont know if its the N 10/3 or N 3/4 module.

Also Ive noticed for some time that the Interior light wont go off if you leave it on. Its supposed to go off after 30 mins and it used to. Any ideas will be appreciated.

Cheers

Graham

Hi Graham.

Unfortunately I don't know anything about your Lack of Boost problem (I run a 320 which doesn't have a compressor) but there are companies, at least in the UK, that recondition some of the ECU's. What makes you think that you don't have boost?

However, I have been working on an Interior Light problem which sounds similar to yours. Maybe you could provide me with some extra data. mileage, owners, use etc and more detailed symptoms.

Bottom line is that it looks as though you need a new PSE unit also!

I have set myself a challenge to understand and repair this relatively common problem without purchasing a new PSE ECU which is situated on the RHS of the boot. New PSE units cost circa £300.

Be very careful with second hand units. Pt. No. / Issue level and electronic coding differences between models / markets (which require access to MB Star Diagnostics system to recode) can make good second hand units a bad buy. Since changing the unit is less than a 5 min job ensure that any second hand unit actually works in situ before paying.

The common failure mode on this unit appears to be water ingress even if there are NO OBVIOUS external visible signs of water ingress. Water enters the ECU through the WHITE multipin connector situated on the front LH side of the unit in plan view. (Check VERY carefully for any signs of blue copper salt deposits between pins). Water travels down the leads into the connector which then enters the unit due to poor gasket design / manufacture. The actual amount of water ingress is minimal but since it drops onto the CAN circuit on the INTERNAL printed circuit board (which provides digital connection between ECU units around the vehicle) electrolysis takes place and somehow (I'm still working on this) the CAN sends an incorrect signal to the N10/3 Body Control Unit (in box under the bonnet) which overrides the N10/3 soft fade functionality. (The two leads coloured Green and White on the PSE White multi connector are the CAN). Out of interest what happens when you disconnect the White connector? Does the interior light "fade" now work albeit that the doors still don't turn it ON / OFF?

The PSE unit contains a strange mix of components. see image attached. Mechanical relays, Vacuum pump / switches, Security logic circuit, and electronic data processing / signalling components.

My view is that such components do not exist well together since failure in anyone of these 3 main systems renders the whole (expensive) unit inoperative. Mechanical components usually give more problems than electronic ones, unless water is present.

I have examined several failed units taken from MB scrap bins and all show exactly the same failure mode. I believe that the root cause of water ingress may be due to stowing a wet roof in the boot since water rolling off the roof subsequently rolls down the boot trim panels,then onto the top of the foam box that houses the PSE unit, and then down the leads. The white connector is more exposed than the Black one. However it may just be down to condensation forming on the wires in our "damp!" UK climate but I think not. Need to check out the detail design on the new SLK before I write to MB.

The bad news is that despite making good any visible damage to the circuit board the system still fails to operate correctly. When I have a little more time I intend fully understanding the electronics but this is on hold since Hella Germany who make the unit were unwilling to provide any assistance. It will take time to backward engineer the circuit.

Do NZ cars use a security system that includes Anti-Tow and Internal Movement sensors. I assume that these don't work since they are connected to N10/3 by the CAN?

Any additional data that you, or anybody else, can provide would be greatly appreciated.

Purchase of my next car (would like an E430 estate) will be dependent upon what sort of response I get when I eventually tackle MB.

Stuart.

Thank you Stuart. The lamp issue doenst seem to be water damage. The lamp system works in all ways excep that if you leave it on at the dome switch it never turns off. It used to but I notice that it didnt after MB tech was stuffing around with the remote controll coding.

My supercharger has no boost beacuse the waste gate or recirculating valve doesnt function and the Elec clutch on the supercharger pully is on constantly at idle. It is supposed to cut in as you rev the engine or when under load. It was working fine untill a week ago.

The car is 1998 Model and imported from Japan. I have owned it for the last 2 years and only done 8000 ks. It lives under covers in my garage and the only water it sees is an occasional wash.

The N10/3 module which is the apparent culprit seems to have something to do with just about everything. SOemtimes I wonder that car makers make things too complexz for their own good.

I was thinking about buying a new C or E class but after all the stuffing around by the MB dealer I think Ill stay with Australian Holden good ole GM product. I have several cars and the MB has been the most trouble of all.!!!!!

Cheers

Graham

quote:

Sometimes I wonder that car makers make things too complex for their own good.

i fully agree with this.

Hi Graham,

Japanese spec vehicles don't have Hi tech security features. There is very little car crime in Japan. Unlike the UK!

Please describe your interior light problem in a little more detail.

"The lamp system works in ALL WAYS excep that if you leave it on at the dome switch it never turns off." What exactly do you mean by ALL WAYS?

There are two switches.

1. A PUSH BUTTON which simply turns the interior light ON/ OFF. Not sure if there should be a 10min+ timer on this circuit for your spec / market of vehicle.

2. A SLIDER switch marked O/I which selects the DOOR OPERATION. When you select Doors (I) from inside the car with doors shut, does the Interior Light stay OFF until the doors are opened? When the doors are SHUT after the light has been on it should SOFT FADE after a short period of time unless the IGN is turned on at which point the interior light should go out immediately.

Maybe I misunderstood your posting.

The PSE problem that I have been investigating is as follows: When you select DOORS using the slider switch the interior light comes ON irrespective of door position, ign setting etc. VERY SMALL QUANTITIES of water cause this problem (possibly aslittle as 1 or 2 drops) is all that is required and is only visible by the damage it causes to the printed circuit board tracks.

Look forward to your reply.

Stuart

The Switch on my SLK is a rocker type with three positions. Off always, on always or dorro activation.

In Door activation the light goes out after five mins if you leave door open with no key in ign.
In the always on possition, the light should go out after 60 mins with no key in ignition.

My problem is that it never goes out in the always on position. Looks like it is part of iether the problem I have with the N10/3 module or it may be programable. (MB dealer function but they seem to be dumb!)

Also the Remote key frequency is different for JAP models compared with Euro/USA models.

Cheers

Graham

Graham,

Your vehicle is a very different spec. to mine.

However I can state that the "Soft Fade" and "Battery Conservation" features are controlled by the N10/3 module on a UK 320 2000m/y spec so it looks like your problems are related.

Sorry for the confusion.

Hope you can get it sorted without spending too much money.

Regards,

Stuart.

the dome lamp got 3 switch position... off, door and on.

was it on the door position?

send your SLK back to the agent and ask them to check it for you if not ask them to bring back to stuttgart's mercedes-benz workshop.

Hoping someone will see this post. the car is the slk 1999
symptoms: 1)Intérior lamp stay on,
2-)all windows don't move by either s84 switch or s21-1 or -2.
3-) s84 light  won't glow at ignition or  when activate
4-) when remotly unlock or locking doors, the rightr side flashers turns on  only.
5-) door won't look when going on the road
6-) For sure the roof doesn,t move :-)

With the troubleshooting procedure, first I'm suppose to look at the TERMINAL 15!!!???? someone can tell where to look for that terminal

Hope someone already knows that problem

What works, The doors can be lock and unlock remotly, panic button with trigger the alarm. I clean all contact at the pse pump what quit fine, a bit of corrosion

thanks in advance for your help

sined
 

Hi sined,

I note this thread goes back over a couple of years.
Have you had problems all that time or did you get it sorted and it has gone wromg again? If so what was the original cause?

5. Easy. You just need to programme auto locking. Press "Door Open" switch in the dash for a few secs and it will flip/flop the auto lock state. If this doesn't work then it suggests the PSE.

Don't understand the connection between Interior light problems and roof will not operate other than it is possible (don't have a WIS to check) they both have the same power feed through the N10/3 underbonnet body control unit which is "activated" via the CAN.

As I stated 2 years ago and now have a much better understanding an interior light that will not go off is likely the PSE./

You state:
I clean all contact at the pse pump what quit fine, a bit of corrosion.

Not quite sure what you mean by this but if corrocion is present on the White multi connector it is 95% confident it is yopur PSE (electronics part of module) that is wrong and this is possibly backed up by the loss of your auto lock. Basically the CAN (digital highway) gets shorted and the N10/3 doesn't get the correct signal.

Stuart.

Thanks Stuart,

Before I trow my pse unit, I need to find out why my light in the s84 ( roof switch) doesn't light. My feeling is that I have a short or a bad contact somewhere. I saw that thread and I will give a try. I did ordered a multiplexor with carsoft 7.4 and also the  supposely complete service book for the slk part number P270017006.

  1998 - 2004 Mercedes-Benz 170 SLK-Class Chassis Family Factory Service Manual on CD-ROM

I will try this.
http://forums.mbworld.org/forums/showthread.php?t=202657&highlight=n10-3

DO you have some information on this famous CAN channel

Yes on the white connectors some oxydation was there so I clean it with contact cleaner,  Is that enough to affect the digital bus?

tell me what you think.

thanks

Sorry for my english writing, I'm not so good at it.

The CAN (Controller area Network) carries digital messages around the car.

The door switch signal is received by the PSE (hardwired) and then transmitted to the N10/3 Body Electrics controller under the hood which in turn controls the power to the Interior light.

You say oxidation on the pins of the PSE. Trouble occurs when you have some corrosion salts ...light blue powder... around the pins. Removing this deposit does not resolve the problem.

Don't suppose your "family" manual will discuss digital electronics in any detail. Carsoft is good... BUT very expensive. Suggest you might be better getting the codes read by an MB dealer. Body codes are on a different CAN to the engine codes which have now been standarised and can be read by most scanners.

Stuart.

snanceki , Stuart,  thanks for the help you give to this  forum,

I finally fix my car, I just want to give an update for anyone who might have similair problem.

I had bad contact or bad solder in the Hasard switch panel, the PSE pump contacts, the relay module, and finally a dead N10-3 module.

In my case, the N10-3 was the final cause. Funny thing is I didn't have to go to the dealer to do any programmation when I replace this module.

I guesst it was just a question of time for all the others one to come up. Bad contact/ solder, corrosion will become a nightmare with the age of the car, and as we know, every year some electronic devices are added, for safety, economy and confort.

For any SLK owner, I strongly suggest the cd-rom book , part # P-2700-170-06, with the on-line website information, who gave plenty of information and electric deign. a must

cheers