SunnyRayToronto

How did that wire get damaged? Are there pictures? Is it mice chewing on wires or leaking oils ending up at the connectors? Is that part of the main wiring harness that is prone to oil damage from leaking cam sensors on M271 engines?

SunnyRayToronto

ZZZ, please post the part number of the wiring harness that they put in for you.

I find your case quite interesting, it mirrors the CLK Cooling Fan Running Continuously problem; which had the "Coolant Visit Workshop" warning along with the front radiator (cooling) fan running in high mode like a turbine engine. Many CLK owners have also replaced their front radiator (cooling) fan thinking it was defective when it was not the source of the problem (as in your case). Some have also replaced their ECU as well (as your Mercedes-Benz Stealership suggested you do). Turns out, like in your case,.... it was the wiring harness between front radiator (cooling) fan and ECU at fault!

Here's the Mercedes-Benz technical service bulletin for the CLK problem:
http://www.justanswer.com/uploads/rm...17_aFinal2.pdf

I wonder if this is a systematic problem that isn't just limited to the CLK,.... especially since the CLK (W209) and our generation of C-class (W203/CL203) share many of the same components and design.

In the case of the CLK, their fix is a new adaptor wiring harness (Mercedes-Benz part# A209 540 56 35). Hmmmm,.... would this CLK wire harness fit on our W203/CL203? I'm wondering if its the position of this wiring harness near the bottom of the front radiator (cooling) fan that makes it prone to catching fluids like water or dripping oil that cases corrossion or bad connections at the connector that makes this wiring harness less effective. To minimize wiring needed, Mercedes-Benz varies the signal strengths between a sensor and computer module, with different signal strength meaning different things,.... but a bad connection due to corrossion or oil can weaken the signal thus confusing the computer module.

Anyways,.... if anyone has the same problem as ZZZ, the OP, with "Coolant Visit Workshop" and continously running front radiator (cooling) fan,.... it's likely NOT a faulty front radiator (cooling) fan, nor is it a faulty ECU (the Mercedes-Benz Stealerships much be making a killing on these ECU),.... but its likely the wiring harness between the front radiator (cooling) fan and ECU,.... can be replaced or probably just cleaned with something like CRC QD Electronic Cleaner at connector. Needless to say, this is just another case where checking the most inexpensive item first,.... will probably fix your issues.

zZz

Will do as soon as we get it done... Our technician wanna replace the main wiring harness instead of only one of them going to the computer or to our a/c control unit. Both are lots of work so he wanna make sure the problem is fixed at once. Hm I wouldn't call it inexpensive... Will be around $1500 bucks :O

In comparison with the CLK I can't give you an answer or just an idea. I have no clue. Sorry.

SunnyRayToronto

Do you have a cam sensor magnet leaking oil? Check front of your M271 engine for oil leaks, there was a recall in USA. Anyways, you don't have the leaking oil problem,.... I doubt you would really need the main wiring harness replaced. Its a $500 wire!

Just wondering,... is this the same Mercedes-Benz Stealership/mechanic that insisted you change your front radiator (cooling) fan without adequately testing it,.... the same one that also suggested you get a new $2400 ECU.

From what I know of the CLK problem with continuous running front radiator (cooling) fan,.... sounds exactly the the same problem you're having with your 2004 C240,.... all they needed was a new redesigned wire from front radiator (cooling) fan to ECU,.... they did NOT need a new ECU or replacement of the main wiring harness.

Personally, if I was you, I would only ask them to replace the wire from the front radiator (cooling) fan to ECU,.... replace and clean all the connectors,.... it should be relatively easy to do,... accessible from bottom of car where wire attaches to bottom of front radiator (cooling) fan, so the bottom panels will have to come off,....

I think they wanting to replace the main wiring harness to "make sure the problem is fixed at once",.... is really just their way of padding their wallet,.... with YOUR MONEY!

zZz

Probably you are right. Assuming we replace it on our own... What are the instructions exactly? What about the voltage e.g? Anyhow I can't believe it's "just" plugging the new one in.

No it's the other technician I got the 2nd opinion on it. He actually found the problem. MB dealer -> *****

SunnyRayToronto

That wire from front radiator (cooling) fan to ECU should be just plug and play,.... make sure the car is off when disconnect and connect the wire. Actually, first I would go to the Mercedes-Benz Stealership to see if that particular wire has a new revision,... if so get the latest and greatest (the CLK wire had an updated version - maybe different built in resistor or something),... otherwise, just focus on cleaning the connectors at both end of your wire with an electrical cleaner like CRC QD Electronic Cleaner. Should be quite simple.

The main wiring harness,.... would be a pain since there are so many connectors and they're all over the place,... its like dealing with an octopus,... still manageable but tedious.

babybluebenz

hello everyone! my 1st POST!! hope its ok kinda a summary of sorts
I have a 2002 c230k (M111) 6spd with about 90k mi
I bought her with 27k mi ...only small glitchy things from 27k-90k ie: rear dome light off/maybe bulb,trunk/boot will only open by hitting green button on hatch,replaced ALT @ 80k,hmm left side control on steering..used to flip through the display stopped working, may leak oil @ oil filter screw in,...ok now we are up to date,,,i just checked the (camshaft magnet sensor) shoot, its leaky! all gunked with oil INSIDE the harness clip and magnet clip and down to the coolant sensor..(the rest of the harness looks safe).....wavy dream bars start now, super hot day 110f, phoenix, i never use the a/c..i dont like the drain & the cost of gas etc..boom! she's overheating..
i manage to get back home...lets start looking ..in the morning i check Cam magnet Sensor, remove,clean,dry, next day re-install ..now it won't even turn over! ahh! waiting for part to come via autohausAZ ..now i'm worried new part comes and she still won't start..thinking i should order the CPS too!! eeek mo money! my reasoning on removal due to seeing coolant sensor&cam magnet oily i figured that all other cooling systems appeared normal fuses fan thermo etc..
thanks for looking, will post pics soon, any thoughts greatly appreciated .ps. with all that jazz outta the way and being stuck i plan on SC silence delete ..is that a E14 torx for the bolts going down into SC, thank you!!

zZz

If it's that easy oh my gosh that would be awesome
Will call the ***** tomorrow and ask them if there is a revision. This wire is about $500 u said? Do we have to delete the warning with a system or disappears it as soon as I turn the engine on?

SunnyRayToronto

Main wiring harness is about $500,.... I doubt you really need it.

The wire between fan and ecu is probably like $25,.... But unless it's a new revision you could probably get by with a good cleaning at the connectors.

Coolant visit workshop message should disappear on its own once fixed. Stored fault codes could be deleted with MB Star Diagnostic System,.... Some maybe with obd2 scantool

bargainfinder

@zZz I was just curious as to whether you had the codes read with a star prior to finding the problem.
I have the exact same problem on a 2001 C240 and the vehicle is throwing the following code:
P2073-004 - Electric suction fan for engine or air conditioning:Open circuit(P1999)

King Z

OK I have the same issue Coolant Visit Workshop message. I also have an A/C clicking issue as Ivanrad wrote earlier. The clicking comes on and off from time to time its annoying!

@zZz did you have the A/C clicking issue and is the coolant problem solved after changing the wires?

zZz

Called the *****...They said they just offer the main harness which is $800. So where can I get this stupid wire from? Can't believe they don't sell it. Ridiculous. Do you have an idea? Aftermarket? But probably this is a "special" part you can buy only from MB right?

@bargainfinder Yes they did but I didn't ask for the codes. They just told me after replacing the coolant fan/module our ECU isn't responding anymore so we have to install a new module.
@King_Z No I don't. But our technician checked the water pump just in case but it's ok. Not yet but I'm working on it getting this wire from somewhere

King Z

I will check with my repair shop to see if they can find an aftermarket. Do you know what the wire looks like? How are the connections?

King Z

@zZz

I took the car in. They checked the fuses and one of them (the one for the fan) was out. They popped in a new one and bam. The fuse burned again. There is a short. They checked the fan by hooking it up to a battery and the fan was bad. They changed the fan it was $610 with their discount from the dealer. It worked fine for 5 minutes than the message Coolant! Visit Workshop! came out and the mechanic checked the fuse again and it had burned once more. I will take the car back on Wednesday so that they can check the wire from the fan to the ECU and check the old fan again once more. Maybe miraculously the old fan will start back up after checking, cleaning or changing the wire. Than they can return the fan back to the dealer and save me some bucks. I doubt that will happen but we will see. I will keep you posted.

zZz

Which fuse exactly was it? The one you plug in next to the coolant module? Does this wire go to the ECU? And where exactly was the short? What did your mechanic say what caused it? Is it possible the short damaged a computer module? They also replaced our fan but the warning is still shown.

davidinfla

does anyone know what wire/ color, and in what wiring harness?

davidinfla

what wire? color, and what harness?

King Z

the fuse was in the fuse box towards the drivers side close to the windshield,, he didn't have time to look for the short yet,, he will check it tomorrow when I leave the car by him,,, although changing the fan didn't solve the problem the old fan was broken,, he hooked the old fan to a battery and the fan didn't start up,, well lets see what he finds out tomorrow, I will keep you posted

I really don't know the wire yet. I just read about it here and the mechanic will check it tomorrow,, he is a reliable guy so he won't rip me off I know that,, I will post again tomorrow

zZz

[QUOTE=King Z;5238329]the fuse was in the fuse box towards the drivers side close to the windshield,, he didn't have time to look for the short yet,, he will check it tomorrow when I leave the car by him,,, although changing the fan didn't solve the problem the old fan was broken,, he hooked the old fan to a battery and the fan didn't start up,, well lets see what he finds out tomorrow, I will keep you posted


Yes please do so... we also checked our fuses even the relays but everything looked fine. Seems like we have to change the main wiring harness since our stealership doesn't sell the wire from the coolant fan to the ecu. Looked online but couldn't find anything so far.

madmdx

This problem happened to me once.
I topped up the coolant.
Message gone.


About changing the entire wiring harness...
What is damaged? Have the terminals corroded? I'm surprised a corner garage would call an entire wiring harness... I'm curious why it cant be fixed

King Z

Update: The mechanic checked the wires and said no problems there. He put in a working control unit from another car and that didn't work either. He can't find the short. He is going to check the climate control knobs (air distribution control switches) inside the car cause the air seems to go on for a few seconds from time to time even though the fan is at 0. He is thinking maybe that it is related somehow.

King Z

OK the mechanic finally found the problem. He said that there were some wires going under the battery that were damaged and were causing the short. Now he is going to put back the old non-working fan to try to see if it'll work. I hope that it does work and I save some bucks.

SunnyRayToronto

Did you get a look there under the battery? If so, did you see a water line? The wires under the battery are prone to damage when there the water drain (grey color tube at corner of engine bay by firewall) are clogged with leaves from windshield or mud in the wheel wells drainage holes,... as a result a little pond of water gets formed under the battery. Obvious rust and corrosion problem.

Check both side of car, at other side, if another little pond of water forms due to blocked drainage, it can damage front SAM and fuse box which are in water tight black box that are designed to protect it from rain splash water from top,... but not designed for being submerged in water!

King Z

No it was not from water damage. The mechanic told me that it was squashed und the battery. He also put back the old fan and YES the old fan worked! So he will be returning back the new fan for a full refund! OK now I just need to fix the A/C clicking noise (actuator) and find out why the rear sunshade doesn't work. I just checked the fuses for that and they're all OK.

jrod73

I am currently have the same issue with my c230, as steveL1 with the fan turning off after awhile and not blowing cold air with the visit workshop being displayed. Does any one know if that issue was ever resolved???