crackerjack

2011 E350 check engine light (OBD II) code P0128 coolant temp below temperature value. This is the code that shows up but the car warms up in the same amount of time and attains the same 80 C, with heat and all things appearing at the same warm up time before the light came on. Upon searching the internet that the coolant temp sensor (ECT) could be the culprit. Does anybody have information where this unit is located and a temperature verses voltage chart would be to trouble this item.

konigstiger

Clear the code to see if it comes back. If it does, note original thermostat was modified current part # is 2722000415 and if steadfast in changing sensor current part # is 0009056102.

MBNUT1

Why can't i see the attachments? Just get a black screen

timannnn

right click on attachment and select "open link in new tab". Usually works.

MBNUT1

Thank you for the prompt suggestion. It did work sort of It showed up in the other tab but was tiny and when I zoomed it it was unreadable

MBNUT1

Another question I have looked online for that part number and they say that it is a 100 deg thermostat. My car runs about 85. Do I really want that?

KEY08

You do realize the temp shown in the gauge cluster is Celsius, right? When the thermostat goes bad it will default to a wide open situation and your car will run cooler than normal and you will get a constant CEL. Sometimes as it's going bad the CEL will be intermittent, but eventually stay on.

konigstiger

See if this works.

MBNUT1

That worked thanks.

MBNUT1

Yes I get that it is Celsius.

Your response implies that your correct functioning thermostat is running at 100 degrees nominally. Is that correct? If that is the case then I am good to go. I thought I had read others indicating that their temp gauge typically read lower more in line with where mine is currently stabilizing but as you suggest that could be that it is running low because the thermostat has failed wide open.

My concern is that the replacement thermostat is designed to run hotter than the original and will require the ECU to be adjusted not to throw a fault because it is running hotter than the software thinks it should.

kash2014

I got this code last week. luckily I still have the ELW, will let you know what dealer does next week

MBNUT1

Would be helpful if somebody reported what the correct running temperature is.

KEY08

Seems all of my E class cars have been a tick over 85c. My 2010 E550 Tstat failed and the gauge was reading around 80c and the CEL was going on and off and then went solid. Same fault code.

Tump43

This was the same for me as well. Replaced the thermo on my C55 to get it a click under 85c.

MBNUT1

Thanks that is where mine running now which is why I am a little concerned that the replacement part is reportedly a 100 deg C thermostat.

https://www.eeuroparts.com/Parts/508...FVtLDQodMboMFQ


I am going to wait until Kash2014 gets his replaced next week and he can provide the part number and the post fix running temperature.

E350Phil

I have the P0128 code on my 2011 E350 3.5L. It's still there after I replaced the thermostat, so now I need to replace the coolant temp sensor.

I looked at the diagram in this thread, and looked all over the engine and can't find that little thing.

Does anyone here have the same or similar year/model that can upload a photo of where that little sensor hides on the engine?

I even took off the blower motor to get a better look at the engine, but it's not under there either.

2011’E350 benz

HEY E350PHIL I RECEIVED THE SAME CODE THIS PAST WEEKEND TEMPERATURE GAUGE ON DASH READING NORMAL. WHAT STEPS YOU TOOK AFTER REPLACING THERMOSTAT AND THE CIDE WAS STILL THERE?

Looser

2009 W211 E350
My CEL still on after replacing the T-Stat and housing complete. Cant clear code with ODB-2 can I clear with onboard computer or is it possible the new parts are bad. ?
OE Mercedes parts from FCP.
and now that I look at the old part it looks great, nothing wrong with it.
Temp Climes to 80C in car, both before and after the repairs.
any ideas ?

xbzus

Hi, Same error 2014 E250. Xentry diagnosis says heating element of Adblue tank is 30ma instead of > 400ma. I saw the other post of ML's replacement, does anyone have E Class? or know if it can be replaced from trunk? I would like to know if that is something I can replace on my own. Thanks

konigstiger

There is a pre-heater repair kit available (50 in diagram), current part # 2124710575. See attachments if need be.

xbzus

Perfect. Thanks for the details.