Hello,

had a CEL come up got it checked and comes out to be P0128 , they said it's related to thermostat and coolant and all.
Checked in the W203-W204 thread and they say thermostat is bad if the constant temperature of car even after being warmed up at less than 80 C or 176 F . Mine is little bit over that hence there is something else wrong.

Did any of you E55 owners suffer through this ?
Someone also said this code got thrown because his battery was dieing?

Any help would be appreciated. Thanks in advance

 

all the threads with the same code have no conclusion ?!

 

Replace the thermostat.

 

Is there a DIY ? Some also said it sometimes is just thrown cuz of cold weather. These days we have ~ -27 to -36 Celsius so -16.6 Fahrenheit could it be that ?

 

Well, I've never seen that kind of cold ever. Hahha..Anyhow, the code is usually set when the ECU sees the engine taking too long to warm up, usually meaning a thermostat that is stuck open. With temps that cold, it may be just the extreme low temps extending the warm-up time. You can always remove the t-stat and see if it's stuck open. Not sure if removing the hose would allow you to see it.

 

Where is it located ? and is it a DIY ? what do you mean by stuck open? pics ? anything ?

 

Clear the code.. Wait for some warmer temps and see if the code returns.

 

Follow your upper radiator hose to where is attaches to the engine; that is the thermostat housing.

 

Stuck wide open means ? it will cracked or something like tha t?

 

Google image search is your friend

 

This happened with me cuz of extreme cold temperature and car taking little bit longer time to warm up.

Just a closure for anyone who ends up encountering this Code:


1. Reset/Clear the code, see if it comes back up.
2. If it does come back, replace Coolant Thermostat and Thermostat sensor.

Could it be done at home ? Possibly but I have no clue how to do it.

Some C class owners with kompressor has also reported of a faulty battery throwing this code but I think that doesn't apply to our cars.

 

What kind of temps were you seeing up there? We recently had some nights around -10 F

 

dont change anything yet. i pushed the car cold once and the code came on. went away in a few days.

so i would clear it and just wait and see.

 

hes talking about -20c.

 

Yeah yeah that's what exactly I did. I wrote the steps down so if anyone else runs into this problem and searches for the same code , has a solution to look over.

I also cleared it today, I hope it doesn't came back on.

In Ottawa with windchill and everything we had around -25 Fahrenheit but now it seems all will be back to normal temps lol

 

So do you have to drain the radiator to do this? It looks like you could just take the upper radiator hose from the thermostat housing and take the housing off and swap it out. Of course, everything on my car seems to take me longer than most as I try to be meticulous and clean but still manage to screw something up!

 

If you are planning to change the Thermostat, it could be done without draining the coolant but it's recommended to change it while you are at it.

 

Just removing the T-stat drains a decent amount of coolant, you may as well replace it.

 

Got the code for the first time a couple of months ago... Had the thermostat replaced at the dealer... Now I got the code again... Maybe the sensor this time?

Anyone have the DIY for our vehicles?

 

Like most of the other posts, clear the code and see if it pops back up. I would get it all the time in my e350 and nothing was wrong. If the car times out warming to 80c the code will flash. This happens to happen when its really cold and the car has not been driven. Probably what happened when you had it replaced also. If the code comes back on clear it again. I never cleared mine. The light went out after a few times and then three months later would pop back on. I just started to ignore it, knowing what it was.

 

Have owned the car for 5 years now and it just started doing this. I cleared the code several times prior to having the thermostat replaced. It didn't throw a cold for a few weeks after the thermostat was replaced. It was in the upper 60s when it threw the code again yesterday... It's been driven in -15 degree weather when visiting family (just last December even) and never threw the code before...