I've been trolling here for awhile, but this is my first post. I read a lot and have yet to find any solid information on the specific CEL Code:

P0128 - Check Coolant Valve (something along those lines for the message)

http://www.obd-codes.com/p0128 (some info related to the code, i've found)



I know the code does not in essentially hurt anything in the engine so I've reset it considering it's telling me my engine isn't up to normal operating temperature in a set amount of time. I was wondering what are the necessary steps to fix this CEL?? Changing a faulty thermostat?? Even though my car is running fine... I'm kind of lost on where to start on such a broad CEL code.

TIA
Craig

 

Anyone, not even a single view doh!

 

Tell us more about your car.
First question, are you the original owner?
Second question, Did you know some of the early LOW temp thermostats (aftermarket) would throw this code.
Here is a link with some info,
https://mbworld.org/forums/w211-amg/...hermostat.html

 

2nd owner, as I know the original owner and the mechanic who has helped maintain this beautiful automobile... I'm coming from a highly modified supercharged audi that was hit head on by a drunk driver when there was 4,300 miles on a built eurospec motor. I'm 98% certain that there isn't a modified t-stat on the car - however I am looking to purchase one considering this code seems to be related to that. It's also been pretty cold when this code has popped up twice. Sub 32 Degrees at night in NJ.

 

Sorry you are not getting more responses. The guys are this forum are just awesome but gotta admit, this ones kinda rare so there may not be a lot of guys with "Hey I had that and here's what I did..." responses.

Quick check of the code on search engine only turned up a handful of people with problems.

Benz sensors go bad all the time so if it's not your thermostat, I would replace the sensor next.

Not sure where the darn sensor is for that but if it's cheaper, maybe swap the sensor first.

Any overheating problems?

 

Thanks for the response! To answer your last question no overheating what-so-ever. Additionally I understand there isn't much technical information available for such a car that usually isn't looked at the by the end user as much. I plan to help this community as I did the Audi community with making a 3.slow into a beast of a car (even though they said there were only basic mods available... that's why I had a custom built motor that dropped the compression, right!!?)

This is a little off topic but here's a link to my pictures of the car 3 weeks before it got macked by a drunk driver head on at 80MPH - the car saved my life.

http://www.audizine.com/forum/showthread.php?t=241670

 

On a side note, what sensor do you suggest replacing if we can rule out it isn't a bad t-stat?

 

I may have had that problem when my CEL went on couple of weeks ago. I wasn't sure of what the code was since I just took it to the dealership, but I believe they said it was the coolant valve not opening or closing correctly. They had to replace the unit I believe. I have the documents at home and will check on what it was exactly.

 

[QUOTE=Craigo;3372886] I understand there isn't much technical information available for such a car that usually isn't looked at the by the end user as much. QUOTE]

Here is a goodly amount of information for us Tech/diyers.

http://www.startekinfo.com/StarTek/

 

Do tell, thanks! How much was the repair, or at least the cost of the unit? TIA

 

Thank you, I guess I need to register for that too in the coming days.

 

Ok I've got the repair sheet here, it says they performed a SDS short test and came up with code 202C-008, I'm not sure if that's the equivalent of this OBD-II code but it sounds very similar. It continues on to say they found the actual value for the coolant temp not rising with vehicle warm up. They determined thermostat was not closing completely. They replaced this part, part number: 113-203-02-75 . I'm not sure how much it costs because it was done under warranty. Hope that helps.

 

Thank you, I'm going to be doing a full coolant flush this weekend and just going to run distilled water and water wetter - no more coolant/anti-freeze for mwah! While doing that I'll check out the T-stat.