jazzj

Gang,

Need you help - out of no where, I turn the car on and straight away notice the fan activate at 100% even though it hasnt been anywhere - then a warning light comes up "Coolant - vist workshop!".

I obviously go to the workshop to get things checked up, had the thermostat replaced, then was told, sorry " theres nothing wrong with your fan, your connection between your fan and computer is stuffed - you will need to order a new computer from Germany - it will be $8000." I have since received a second opinion and confirmed this to be the case.


I now write on this forum in desperation, can anyone recommend any options, I cant afford a new computer!" Am I really screwed, any suggestions to help a fellow driver out would be appreciated!

jazzj

apparently this happens quite often to CLK55's and CLK's in general, its well known. I guess not based on the level of response!

elijah

I'm in the same boat as you.
My fan started spinning @ max rpm 3 weeks ago. First dealership no had idea what the issue was. They didnt go far into details all they wanted to do was to replace my fan for 1000 (labor included) and werent even sure it would fix the problem, I said no thanks. Did some research and found it's a common problem on our cars.
The solution to our problem is in the link below
http://www.justanswer.com/uploads/rm...17_aFinal2.pdf

I thought I would only need to plug in the adapter. Took the car in yesterday, gave them the above document and told them not to replace the engine unit but only install the adapter and they said OK. Later on I received a call and the guy tells me he does not want to just install the adapter as it might "harm" the engine control unit and i told him NONSENSE! After 10minutes going back & fourth he just wouldnt do it. To fix the problem I need a new engine control & the whole job would cost me 4550$.
I told him forget about it. Im picking up the car in about an hour to take it to MB across the border to France to see what they've got to say about the situation.

I really don't think my engine control unit is faulty because when this first happened, MB diagnosed the car thoroughly and found no defects at all.
As soon as I came to them with a solution, they were not happy at all. They absolutely hate it when you bring your car in and tell them what to do because their job is to replace parts here & there that don't need to be replaced and eventually fix the problem but bringing your bill sky high.
I even asked him to just disconnect the damn fan and he said no I don't want to take the risk etc...
Really disappointed with MB Switzerland, lets see what MB France has to say. In any case they're 20mins away and their prices are -30 to 40% compared to Switzerland.

DRBC43AMG

Now you can understand why I don't go to a MB dealer, not unless I break down in front of the place. As soon as they see an AMG, you can see the cash register going overtime. I use an independent but a highly qualified technician and a specialist in MB vehicles (was a senior technician with MB Switzerland until he got fed up with their strategies). An expert with older MB, less so with the modern electronic filled stuff you find today. If you need further info send me a PM

elijah

The only reason I brought it to MB is because I havent been able to find an MB specialist in my area. I'm sure they are a few, as a matter fact I remember driving past guys who only repairs Benz's but I just can't recall where.

jazzj

Guys, firstly, the fan needs to be on, do not disconnect the fan at any time, this has serious consequences and you risk damaging the hand built engine.

The engine computer costs approximately 7500 us dollars + fitting. Mercedes make it impossible to buy computers from any one else these days. This is due to very tight procedures on security with their cars.

It alarms me to hear you are in the same boat. Unless I'm reading the document incorrectly, it states to remove the module an replace. You will still be up for 7200 US$. It doesn't matter if it's a dealer or an honest expert my fear is we only have one option.

If that is the case, i am greatly disappointed in German engineering.

MarcusF

I've built electric fans that replace manual ones. This is slightly different, but the same triggering principal is used. Right now, the fan is always receiving power, so you cut the wire and put in an adjustable thermo switch. If you're unfamiliar with an adjustable thermo switch, it has a sensor that you put in the radiator fins. The sensor is the silver piece on the left in the photo. The black rotary dial in the center of the switch is how it's adjusted. Depending on were you set it, at x-degrees the switch will complete the circuit, turning the fan on. Also, some of these are sold with an AC tap. This allows you to run a wire from the AC to the switch. This turns on the fan whenever the AC is on. Thermo switches cost under $40 and this job would take about 30 minutes without the AC switch. Most of that time would be spent mounting the switch to something solid.





Lastly, I've never heard of MB fans failing like this. Maybe it's more common in ROW cars. If so, possibly it's due to wiring differences.

betrezra

$8K for a cooling module! Wow..... makes me keep an eye out for a wreck clk to scavenge parts.

Nice hook-up Marcus. We use those fan controllers with aftermarket radiators all the time in race cars.

elijah

You did read the document correctly. We had a member a while ago who had the same issue as us but did not have to replace the engine control unit, he simply added the adapter and it fixed the problem. That is what I want to try first, and if it doesn't help well... I'll just have to order another control unit @ 3000$ but my dealership refuses to just add the adapter without changing the control unit thus the reason why I am going elsewhere.
I don't understand why it costs you 7200$ and half the price here in Switzerland where everything is considerably more expensive than in the U.S.

jazzj

Thanks Elijah, it is with some slight comfort I am not alone.

I will try to get an adapter wiring harness as well, part number A209 540 5635 and attempt to have it fitted. See how it goes? Do you have the part number for engine control unit?

CLK owners take note, this could happen to any of you!

jazzj

I'm going to do some checks on the price of the engine contol unit in question, to confirm why I am getting quoted so high? My car is a CLK55AMG w209, built 12/03. Assuming the control unit might be a higher spec?

jazzj

Thanks for the suggestion Marcus, my auto electrician mentioned he could install aftermarket fans an bi-pass the electrical fault in the computer. The trouble is the CLK fan is one of the most advanced in any car built. The fan module is linked to the cars performance.

elijah

Sorry I don't have the part number for the engine control unit.
Marcus' suggestion is appealing, only until I get my hands on a new control unit it might be something to try out!!

elijah

https://mbworld.org/forums/clk-class...pparently.html

Guys, check out this thread. Same issue and in one post it clearly says you might not have to replace the control unit, just the adapter. Hope this will work!!

[EDIT] Found a mechanic in my area who is going to install the wiring harness tomorrow morning. Sure hope this puts an end to the jet engine! [EDIT]

jazzj

For those watching this thread, just replacing the wiring harness didnt work. So now may car is back to the drawing board...

Marcus did post an interesting response about installing an after market fan sensor/switch, but the issue is going to be making sure errors dont appear in the computer, and making sure the signal talks to the computer...

The main issue is the signal from the CLK fan to the ECU is not getting through, hence the computer cant get a reading from the fan, so the engine is going into auto-protection mode, hence why the fan is always on @ 100%...Putting an aftermarket switch on may create some more issues...

Peoples thoughts please? In the past I have heard that the issue we face can be overcome by installing an aftermarket fan, and bypassing the connection between the fan and computer and installing an after market switch...Is there any way I can keep my existing fan, I really dont want to replace my fan and muck around with computer signals if it can be avoided...

ziad-ehden

Hi to all from beirut,it's a comman problem in all the W209's 03 & 04,
every week we have a car to repair!
we take 100$ to fix it.....
if you want a help,call Jerry@eurocharged.com, we work with him,he will contact us & tell you what to do.

jazzj

Hello, assuming it involves repairing the existing ecu? The biggest problem is people would have a big problem shipping the ecu overseas, imagine if the ecu was lost or damaged, no ecu, no car!

If it's a case of getting a particular module within the ecu keen to know.

I understand many people just say Merc ECU'a can't be repaired, but where there is a will there is a way

jazzj

Just an update. I have been working with Jerry from Eurocharged to remotely reflash the ECU to overcome the situation. We did a few tests on thursday and attempted to reflash with new software, unfortunately when we uploaded the latest Merc software for the clk55 the car wouldn't start at all and we had to revert back, and will reconvene this week coming (had a dead battery midway through testing)

We have reverted back to the old software, but the fact the car isn't accepting new software is very strange. Has anyone seen this behavior in an ecu before?

Billy Albert

I am going to try this adapter on my w203 , but the ecu has now been repaired again, those who have tried it will need to get the ecu repaired first, Ill let you know if it works.

Josh Batal

Anybody resolve the issue? I purchased a 03 clk55 amg with the same issue. A MECHANICAL FAN was welded to the water pump. got that out of there. The harness adapter was already installed on the car however it was badly damaged by the mechanical fan running full blast 24/7. i bought a fan assembly and no go when i plugged it in :/ also brought the car to a german car mechanic and they told me the signal from the fan to the computer was intermittent? Any help would be appreciated on the next course of action.

jazzj

The issue is your ECU is damaged. It's a well known issue.

There are 2 options that's will resolve this matter -

The ECU is manufacturered by Bosch, you need to find some (who is willing to repair the ECU boards). I only can speak of someone in Australia.

The only other option is to completely replace the ECU - and this can only br ordered from Germany and is a restricted part which is heavily controls by MB, meaning you will pay 6-7k US. Once ordering a new ECU it doesn't end there, you need to installed and calibrated and new keys need to be reprogrammed.

Good luck, absolute night mate issue that I've experienced

nabiel

Hi check power supply cable my fan stoppedworking because power steering pump pulley cut threw the cable