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[Fixed] Car won't start, cooler fan going full speed !
Hey guys, need some input here !
My car had done this once before, don't know what is it
1-Put key in ignition, everything lights up properly, everything seems ok !
2-Put key in ACC (second click), the cooler fan goes full speed !
3-Try to crank, nothing happens at all !
Here's what i've done:
1-Search online, found a couple similar problems, one fixed it by replacing ECU, other said it was a K40 relay, but never confirmed he fixed it or not.
2-Battery is ok, didn't try another one though.. should I ?
3-Replace the K relay and starter relay, didn't help.
I was thinking about pulling out the ECU to check it for damage, is the ECU the one on the inside of the fuse box (sitting on the wall closer to the fender) ?
it happened once before about 3 months ago, but after a minute it just worked and I couldn't trace it so i forgot about it.
any other ideas ? this is driving me nuts !
Last edited by mostafaberg; 01-24-2015 at 11:02 AM.
Reason: Updating status to fixed
Oh shi.. my psychic powers failed me.
Yeah, then it's either close to the SAM, or on the battery-side.
You need to work on it a little then !
Yeah i guess it's the one in the front sam, I'll check it out later tomorrow.
I'm starting to doubt it could also be the engine coolant temp sensor, since the fan is triggered, dashboard shows no temperature at all (i'm pretty sure it used to show at least 1 bar or 2 on cold start), will try to pull codes too !
Have the car ever stalled? Or does this only happen when trying to start the car?
If you have Mercedes approved trickle charger, use it to keep battery fully charged.
If you're going to be throwing parts at the car, start with the cheapest one first.
- For K40 and starter relay - have KEY OUT OF IGNITION! - open front SAM and switch those relay with another relay of same colour and size - once everything seems fine they try to start car.
- Make sure you upgrade fuse 52 to 20A
- If you could go into Dyno-Mode check voltage or have your battery load tested (it's cold where you are! I'd much rather help someone in a much colder climate than mine - Toronto at coldest part of the year - than help someone who's in a warm climate like Texas where he can't remember your engine generation because he's distracted by all the bikini clad girls around him!)
- Engine coolant temperature sensor is a $20 part so if you want to switch in a new one fine - but I don't think that's your problem
- Check front radiator control module - make sure all wiring and plugs are good.
If all the above is fine,.... then it might be ECU. If ECU is dead or not working properly, then ECU won't send a signal to Front Radiator Control Module - without that signal from ECU, the Front Radiator Control Module goes into default mode and spins at high speed like a turbine engine. It assumes the worst, that engine is on fire or overheating so it spins in high mode.
If you get to this step and all engine wiring and plugs look good without cuts or oil damage then I would suggest you take out the ECU,... and shake ECU to see if it rattles. ECU is all electrical circuit board with no moving parts,... ECU shouldn't rattle but if ECU rattles it means something fell loose off circuit board,... in my case it was crystal oscillator. If ECU rattles then it's best to unseal ECU and resolder anything that fell off circuit board.
If you have access to another ECU with same part number (say ebay) and that ECU is in proper working order, that ECU will have different VIN-code and SCN coding to it won't work on your car. But if that ECU was installed on your car and you tried to start car, if you get more lights displayed on your dash and the front radiator fan does NOT start spinning in high mode, then you'll know your original ECU is faulty. If you get to this stage, then all you need to do is switch out your eprom chip (holds your VIN-code and SCN coding) from original ECU to replacement ECU and install replacement ECU. This would be the cheapest way to fix ECU - by getting used ECU and transplanting the eprom chip holding your VIN-code and SCN coding. The alternative is buying a new VIN-coded ECU from dealer at about $1000 and paying specialized Mercedes Indy about $500 to test, install and SCN code it for you.
Is it an insult? How am I supposed to "remember" his engine generation if he didn't even list the car's mfg year? huh? lol you guys
Just pulling your leg ,... it`s a miracle I could pull anything since I`m frozen in Toronto,.... I can not even imagine how bad it must be in Norway where they don`t even have sunlight now!
Have the car ever stalled? Or does this only happen when trying to start the car?
If you have Mercedes approved trickle charger, use it to keep battery fully charged.
If you're going to be throwing parts at the car, start with the cheapest one first.
- For K40 and starter relay - have KEY OUT OF IGNITION! - open front SAM and switch those relay with another relay of same colour and size - once everything seems fine they try to start car.
- Make sure you upgrade fuse 52 to 20A
- If you could go into Dyno-Mode check voltage or have your battery load tested (it's cold where you are! I'd much rather help someone in a much colder climate than mine - Toronto at coldest part of the year - than help someone who's in a warm climate like Texas where he can't remember your engine generation because he's distracted by all the bikini clad girls around him!)
- Engine coolant temperature sensor is a $20 part so if you want to switch in a new one fine - but I don't think that's your problem
- Check front radiator control module - make sure all wiring and plugs are good.
If all the above is fine,.... then it might be ECU. If ECU is dead or not working properly, then ECU won't send a signal to Front Radiator Control Module - without that signal from ECU, the Front Radiator Control Module goes into default mode and spins at high speed like a turbine engine. It assumes the worst, that engine is on fire or overheating so it spins in high mode.
If you get to this step and all engine wiring and plugs look good without cuts or oil damage then I would suggest you take out the ECU,... and shake ECU to see if it rattles. ECU is all electrical circuit board with no moving parts,... ECU shouldn't rattle but if ECU rattles it means something fell loose off circuit board,... in my case it was crystal oscillator. If ECU rattles then it's best to unseal ECU and resolder anything that fell off circuit board.
If you have access to another ECU with same part number (say ebay) and that ECU is in proper working order, that ECU will have different VIN-code and SCN coding to it won't work on your car. But if that ECU was installed on your car and you tried to start car, if you get more lights displayed on your dash and the front radiator fan does NOT start spinning in high mode, then you'll know your original ECU is faulty. If you get to this stage, then all you need to do is switch out your eprom chip (holds your VIN-code and SCN coding) from original ECU to replacement ECU and install replacement ECU. This would be the cheapest way to fix ECU - by getting used ECU and transplanting the eprom chip holding your VIN-code and SCN coding. The alternative is buying a new VIN-coded ECU from dealer at about $1000 and paying specialized Mercedes Indy about $500 to test, install and SCN code it for you.
That's a wealth of info in there !! thanks my friend !
I'm at work now, but as soon as i'm off i'll get down to business and report back !
-It never stalled, always ran perfectly, this only happens on a start, one time a round three months ago i was driving a friend to the train station, drove perfectly for around 15-20 Kms, engine was pretty warm, when i stopped the car to drop him off and get the baggage out, it wouldn't start again when i got in, engine was warm at that point so it doesn't count as a cold start, after around 10 seconds it started again.
-My car is european specd' so i don't have the Dyno mode feature
-I already tried switching around the relays and that wasn't the problem so i'm going to start with the next steps, I'm gonna look out for oil leaks, wiring seems clean to me but i might have to dig deeper !
Question is, where does the oil usually leak ? any specific places i should look at?
It's pretty freezing here in Norway, not the best times to be having issues like that, specially it's extremely hard to work on it in cold conditions like that (around -10C)
Silly me was happy that the new crank seal arrived (check my leak thread) and i was going to be trouble free for a bit !
Your train incident where you drove for a while (engine got hot) and then it won`t start or stall would point to a CPS problem but as you mentioned the front radiator fan started spinning in high mode when the car wouldn`t start, right,.... that points to ECU. But take all the steps to get to that conclusion because ECU failure are very rare and thus difficult to properly diagnose.
Check for oil leak at plugs by looking around it and unplugging plug to look at connectors. Make sure none of the wires have been damaged,... especially by cuts,... by broken fan belt or something.
Double check the previous work on car to make sure that didn`t cause any damage and everything especially wires where replaced properly.
Nice blue coupey in that video.
Don't think I have an exposed relay like that in mine!
That was 6 cyl, 2005 perhaps?'
Good luck on the fix.
I recall reading threads on same issue around here, but not on the resolution, sorry.
I don't know what model is that TBH, they don't come with exposed relays like that it's too dangerous, the guy probably took off the over himself to show what he's doing !
Your train incident where you drove for a while (engine got hot) and then it won`t start or stall would point to a CPS problem but as you mentioned the front radiator fan started spinning in high mode when the car wouldn`t start, right,.... that points to ECU. But take all the steps to get to that conclusion because ECU failure are very rare and thus difficult to properly diagnose.
Check for oil leak at plugs by looking around it and unplugging plug to look at connectors. Make sure none of the wires have been damaged,... especially by cuts,... by broken fan belt or something.
Double check the previous work on car to make sure that didn`t cause any damage and everything especially wires where replaced properly.
Sure thing, I got to work on the car a bit today, and haven't reached anything conclusive yet, ended up tracing all wiring looms and making sure everything is intact and dry, and it all seems to be !, pulled out the ECU and front sam too, will update the thread tomorrow with all the info i found and i got tons of pics , they just need cleaning up and a little writeup will be on it's way, it's getting late and i have to hit the bed now !
But i think it seems to be a faulty ECU since my OBD2 scanner couldn't connect to the car anymore
Managed to get some work on the car last night, and here's what I did
-Tried pulling codes using my OBDII scanner, couldn't get it to connect to the car anymore, seems ECU isn't communicating.
-Traced cables from ECU all around engine compartment for oil leaks or wet/brittle/broken wires, everything seemed intact and no issues whatsoever !
(Just found that my cam sensor magnet is leaky and managed to soak a sensor, not sure what the sensor was but it surely had oil in it, see pictures below, i don't really think this was the problem though) Note: Can someone tell me what sensor is that ? my guess is the engine coolant temp sensor, but not sure.
-Checked the control box on the other side of the engine compartment (right next to the battery) and boy there was rust under the battery, popped open the control box and it was very clean !
-Checked the wiring from the radiator fan, it seems intact, didn't know how to do a proper test, but it was intact and nothing was loose/broken.
-Then I moved to the ECU/front SAM and made sure all fuses are ok, they all were intact by visual inspection, tried moving the relays around again (using similar ones, etc..) and relays didn't change a thing, they seem to be ok too.
-I decided to pull out the SAM and ECU since everything else seemed ok.
PITA to get the SAM out, but after some work it's pulled out, sam seems clean on the bottom, the top side had some dust and dirt, not extreme, but it was enough to grab my attention.
-Tried shaking the ECU to hear for loose components, no noises there, ECU also is factory sealed and doesn't seem to have been tampered with by pre. owner !
-Put the key in ignition, put key in Acc. (second click), everything seems ok, move the gear around Park/Drive/Reverse, and it updates properly on the screen.
-Checked the water level on the MFD and it shows tow rows of water and the temp. drawing is at it's biggest state, meaning water level is okay.
-Checked Temperature reading, it shows an empty bar, so i assume it's at 0 or that the sensor isn't sending data. not sure what the standard value should look like.
My guesses now is that it could be the SAM or the ECU, but i'm not sure what's the easiest way to get that figured out (Can't really take the car anywhere so it's a bit difficult to get a Star system)
I'll leave you guys with the pics, if anyone sees anything i don't or have any tips please don't hold it back, I'm desperate !
Leaky cam sensor
Oil has leaked into this sensor, is that the temp. sensor ?
Oil leaking from cam sensor into the (temp?) sensor connector
I'm a 271 guy, yours is 111. But I'd say clean off all the oil from your leaking cam magnet sensor and that (temp) sensor. Use CRC Electronic Cleaner. Install pigtail, change cam magnet sensor and (temp) sensor. Do this first and see if it fix your issues.
Your battery compartment looks like it's having water drainage issues (are there any water line), likely from leaves clogging drain holes at bottom. Same thing can happen on other side where Front SAM is.
I'm not sure if those are your main cable plug for ECU, main cable plug for ECU on 271 looks different - so I would expect bigger bulkier weather-resistant plugs.
Where's a photo of your ECU with part number? Then we could at least look that up and confirm its a ECU
I'm a 271 guy, yours is 111. But I'd say clean off all the oil from your leaking cam magnet sensor and that (temp) sensor. Use CRC Electronic Cleaner. Install pigtail, change cam magnet sensor and (temp) sensor. Do this first and see if it fix your issues.
Your battery compartment looks like it's having water drainage issues (are there any water line), likely from leaves clogging drain holes at bottom. Same thing can happen on other side where Front SAM is.
I'm not sure if those are your main cable plug for ECU, main cable plug for ECU on 271 looks different - so I would expect bigger bulkier weather-resistant plugs.
Where's a photo of your ECU with part number? Then we could at least look that up and confirm its a ECU
Search for a blowup of 111 engine
Ok got a little better news now ! i found out fuse 53 (or 54) was blown !, upon inspection it says 53/54 are for "engine electronics" and after opening the front SAM i can see evidence of water leakage, even though it's dry, there seems to be residue of some sort.
I guess that is a good pointer where the problem is coming from ! should i try to change the fuse and see if thing go well ? i'm leaving the ECU and SAM in a heated room overnight and will try tomorrow and see how things will go.
I am sure it's the ECU. but i think the ECU might be fine !
keep me updated with thoughts, i'll order new sensors and replace before completing the job !
Here are the photos : parts marked in red are water residue
M271 ECU are in water tight seal, M111 are in FrontSAM but your FrontSAM seems compromised with water. Important to keep water drain clear.
That said, its very good news that fuse is blown,... ECU are basically bullet proof, very rare for any ECU failure. A good size Mercedes Benz dealership or MB Indy might see 1 ECU failure per year. ECU are protected by many fuses, cuicuit breakers, etc,... that blown fuse probably took the brunt of the damage.
Of course change the fuse. Also need to change cam sensor magnet, (temp) sensor (part number should be on it), and add pigtails
M271 ECU are in water tight seal, M111 are in FrontSAM but your FrontSAM seems compromised with water. Important to keep water drain clear.
That said, its very good news that fuse is blown,... ECU are basically bullet proof, very rare for any ECU failure. A good size Mercedes Benz dealership or MB Indy might see 1 ECU failure per year. ECU are protected by many fuses, cuicuit breakers, etc,... that blown fuse probably took the brunt of the damage.
Of course change the fuse. Also need to change cam sensor magnet, (temp) sensor (part number should be on it), and add pigtails
Also make sure your fuse 52 is upgraded to 20A
Will do that !, heading out tomorrow to buy most parts, anything else will be ordered and hopefully will get it on monday/tuesday !
Yeah that SAM seems like it's been through a bad time, if it won't start after those repairs/cleans i'm probably looking at a new front SAM, hopefully it'll plug'n'play !
Yeah you mentioned fuse 52 ! I'll do that, but why does it need an upgrade ?
So i finally got the car running again !, here's how it went
1-Test all relays
2-Replace blown fuse
3-Upgrade fuse 52 to 20A as recommended by @SunnyRayToronto
4-spend an hour or so getting the whole thing plugged in again (Major PITA !)
Then cranked the car and it just worked like a charm !
thanks a lot to for the help guys !, specially for @SunnyRayToronto and his great info !
Now i just have a couple more things to fix to avoid future leaks
-Replace cam adjuster magnet
-Replace temp sensor
-Do the pigtail fix to avoid future leaks
I have the same problem...the cooling fan is on full speed... I have 08 c300 (W204)...so if ill replace temperature sensor it should work out for me as well?!
My 2005 C230 K died on me going down the road and I have the same symptoms listed except my #53 fuse (ECU Fuse) was blown and blows as soon as the car is put into key position 2 and then the cooler fan goes full speed.
I’m thinking it’s a short between the Front SAM and the ECU because there no noise when shaking the ECU. I was wondering if anyone has more information on this issue.
My issue turned out to be a short in the #2 coil which caused the #53 fuse to blow. The #53 fuse provides power to the ECU and the coils so once the fuse was blown the ECU lost power and that caused the Cooling Fan to run on High speed.
want to contribute to this thread and it helped me troubleshoot and figure out how i solved my crank but did not turn over/start engine.
yesterday, my wife called me stating that the car wont start, we had it towed back home. When the car arrived at home eas able to start car but check engine light with oil temp maxed out 120C+ even with the engine off and key fob on "on" the temperature stated the same as if it was on . After research online and this thread.. i started my troubleshooting on the car this morning.. checked battery with reader, checked fuses everything seemed good, reset the ecu 20 mins with battery unpluged, and did the key/gas pedal ecu reset.... obdii reader state the coolant temperature sensor needs replacing, cleared it to see if it works.. no luck... everything I read stated that the coolant temperature sensor shouldnt be related to the car not being able to starting up.. so my conclusion was most likely the crank shaft sensor.... but since i have to replace the temperature sensor either way... i just started with that since autozone has this for 18 bucks... and I'll order the crack shaft sensor online(cheaper 50+ local vs 17+ online)...
got home replaced the coolant temperature sensor... went to crank to test... guess what happen.... the car turned over/started!! Tested it 4 to 5 start up times including 15 to 20 miles drive everything seems normal now... just waiting for the morning start up.. crossing my fingers.. hopefully this will help someone in the future with the same issue... save them hundreds.. and i want to contribute to this great forum and online resource.
This was an interesting situation that I thought we would share with you. 08/2004 production C230 comes in no crank, cooling fan on high speed with key in position 2 and multiple failure messages in the information center, to include coolant temperature, battery/alternator. display and ESP. Inspection revealed fuse #52 was blown. More invasive testing showed a short to ground downstream of the fuse. Further testing revealed a short to ground on ignition coils #1 and #4, which had been replaced by us with Delphi less than one year ago.
Replacing the ignition coils corrected the short circuit condition.
Posted in hopes this may prove helpful to someone with a similar symptomology...
01-21-2015, 03:53 PM
[Fixed] Car won't start, cooler fan going full speed !
,... it`s a miracle I could pull anything since I`m frozen in Toronto,.... I can not even imagine how bad it must be in Norway where they don`t even have sunlight now! 
That's a wealth of info in there !! thanks my friend !
