[warith]

Hi, I have a 2003 sl350, the car has an overheating issue.. upon turning on the car the temperature light turns on and never goes off even while the temperature is around 40C*.

I took the car to a workshop and they told me that the coolant temperature sensor is bad (A0009050700).their reasoning for why the sensor is bad is, once they unplug the sensor the fan goes on super speed this show that the fan works but somehow it is not getting signals from the ECU to turn on maybe? I went to a local Mercedes yard, got a good working one, and placed it, but the issue remains the same, even with the new sensor once i unplug it, the fan goes on super speed.

I even did a radiator flush and added new coolant but the issue is still there... i want to go through the fuses, but I have no idea where the radiator fuse is.

i bought this car recently with this issue hoping it to be a quick fix but it's proving me wrong.. the car does have other issues but at the moment this is the priority.

any suggestions on what i should check or what could cause this to happen?

 

[Tom Manning]

Nothing quick on an R230. Patience will be its own reward.

Have you pulled the codes?

Your fan control module might be faulty, which can trigger the coolant light.

There are three fuse boxes. Two under the bonnet, one each side up the top of the engine bay and one under the RHS rear cubby box under the felt bottom. Always a good first check.

 

[MikeJ65]

That light is dual purpose. Light only is an indication of low coolant or a cooling system fault. Light with buzzer is overheating. Check coolant level and level sensor, pull codes, and find a different repair shop.

 

[warith]

I went through my diagnostics and found this code right here that might relate to it.

B11/4(Coolant Temperature
Sensor) : Short Circuit To Positive
Or Open circuit(P0117).

could this be a bad fuse?

 

[cdk4219]

There’s no specific fuse for that, so I would have to say it’s a bad sensor or a bad wire.

 

[MikeJ65]

That code was probably set when you unplugged the sensor. Clear it and see if it returns. You need to get a copy of WIS so that you can look up repair instructions, wiring diagrams, etc. I would also recommend DAS if you are going to get serious on being able to do repairs. Other Mercedes specific scanners are fine, but none will do everything that DAS is capable of.

 

[warith]

i changed the sensor and also rewired it 3 times just to make sure and it seems fine. i actually think Mike is right on this one and I have to clear the codes to then test it again.

but yet again if the sensor is fine what could cause the fan to not kick in when the engine is overheating?

i will update you on Wednesday when i get my scanner. ordering from the USA does take a while.

I am still new to this so when you say das do you mean Xentry?

 

[Witek_M]

but yet again if the sensor is fine what could cause the fan to not kick in when the engine is overheating?

What are the symptoms? Temp gauge going into red zone? Coolant boiling out off expansion tank?

Here is page from US SL500 OM.

 

[warith]

What are the symptoms? Temp gauge going into red zone? Coolant boiling out off expansion tank?

Here is page from US SL500 OM.

the symptoms are as follows.

as soon as I put the key on ignition(second click) the radiator light comes on, even if the has been resting overnight.
once i turn the car on the light does not go away and the temperature slowly starts to creep up and goes over 90C* i don't know what that is in F*.


while the temperature is rising i don't see a sign of the fan kicking in to cool the engine. so i shut off the car to avoid damaging it.

weirdly enough i did check to see if the fan was working.. and as soon as i unplug the coolant temperature sensor the fan goes off on full speed. and when i plug it back in it turns off.

Ps: appreciate the info in the pdf.

 

[Witek_M]

What is six digit model designation? Or VIN? SL350 was never imported into US.

 

[warith]

i am not in the US. i am actually in the middle east in oman. they are also very rare over here.

Vin is WDB2304671f053689

 

[Witek_M]

I see your profile.

Muscat · Oman

Oman

www.google.com

So your vehicle is 230.467
Here is link to online parts catalog if you ever need it. And you will.

Mercedes FG 230.467 (65P) > Mercedes EPC Online > nemigaparts.com

Parts catalogs. Spare parts catalog Mercedes EPC Online. Mercedes. Car. Mercedes FG 230.467 (65P).

nemigaparts.com

Take a picture of instrument cluster with warning displayed.

 

[warith]

i actually need to get a new cluster, coz of the heat here and the car sitting iin one spot for a long time i can barely see through the cluster and also everything is in french for some reason which i don't understand.

ill link a picture to show you what i am dealing with and also the temperature light being on at a cold start 😂

 

[Witek_M]

What scanner have you ordered? This sure looks like failure of radiator fan controller. Does ac work? AC should put fan at 30% speed.

 

[tonylinc]

What part on your gage cluster is in French?
Is that red light by the 60 MPH marker indicating brakes?

 

[Witek_M]

What part on your gage cluster is in French?
Is that red light by the 60 MPH marker indicating brakes?

Yes, it is brake failure warning. And most likely message "Stop vehicle, reduced brake performance" in French. SBC fail.
Since it is not visible it is like putting piece of black tape over Check Engine Light. 😷

 

[warith]

What scanner have you ordered? This sure looks like failure of radiator fan controller. Does ac work? AC should put fan at 30% speed.

The AC works and if i turn on the Ac the fan does work.

i got a normal Cr3001 as its the only one in my budget at the moment after high shipping costs.

appreciate the files and the links.

 

[warith]

What part on your gage cluster is in French?
Is that red light by the 60 MPH marker indicating brakes?

i will try and upload a visible one just to show you. but due to the sun damage its very hard to see.

dont worry about the check engine light 😂 we will get to it shortly.🤣

 

[Frederick NL]

You can select another language in the cluster or Comand (nut sure). The message is about engine control and a reset with a knob(?)

 

[Witek_M]

The AC works and if i turn on the Ac the fan does work.

i got a normal Cr3001 as its the only one in my budget at the moment after high shipping costs.

appreciate the files and the links.

Engine coolant thermostat starts opening at ~87C, fully open at ~102C. Without ac suction fan comes on at ~100C.

Scanner that you ordered will not even scratch the surface of R230. You have network of 25+ control modules and you need to access them all. That includes reading faults and actual values.

Computers/Controllers

Sorry if this is redundant. I would like to know how many computers or controllers a 2005 SL 600 has, what they control, and their locations. I'm trying to sort out some operating deficiencies and don't know where to check first for an assortment of issues. Any help is appreciated.

www.benzworld.org