2012 C250 check engine light: P0128
03-10-2018, 08:52 PM
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2012 C250 coupe
2012 C250 check engine light: P0128
The check engine light turned on in my C250 coupe (2012). The OBD code read is P0128 P2005-032 refrigerant temperature rise too slow]. The car has been running fine without any engine temperature overheating. Is this an issue with the temperature sensor or the thermostat or something else? Thanks for the help!
03-12-2018, 08:07 AM
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2016 E400 Coupe (C207)
The check engine light turned on in my C250 coupe (2012). The OBD code read is P0128 P2005-032 refrigerant temperature rise too slow]. The car has been running fine without any engine temperature overheating. Is this an issue with the temperature sensor or the thermostat or something else? Thanks for the help!
03-12-2018, 02:42 PM
#3
Likely your thermostat is stuck in the open position. The part is about $125 (for the Wahler part) from the local parts store and you can pay less if you order online.
Symptom can be that the operating temp is low but I believe it will throw this code if it just takes too long to warm up (slow to open vs. stuck open).
Plenty of DIY videos out there that will walk you through the process.
My tips:
I didn't find it necessary to drain the radiator entirely. Some people didn't even drain the radiator but just let the fluid come out as the parts were removed.
Don't forget to buy some replacement coolant as you will lose a gallon or so.
The airpump didn't need to be removed.
Clean the surface (on the block) well as mine had some of the old gasket stuck to it. (don't 'nick' the surface, gently remove the old material)
In addition to the part I would look at replacing your fan belt if it's due as you will need to take it off to get to the thermostat.
Some semi special tools require: Torx socket for the idler pulley and the thermostat (I think the size is "10").
Note: While I could reset the CEL (check engine light) I had some difficulty resetting the last P0128 code as I believe it is tied to an emissions algorithm. It eventually went away after a few days.
ref: https://mbworld.org/forums/glk-class...orn-p0128.html
Symptom can be that the operating temp is low but I believe it will throw this code if it just takes too long to warm up (slow to open vs. stuck open).
Plenty of DIY videos out there that will walk you through the process.
My tips:
I didn't find it necessary to drain the radiator entirely. Some people didn't even drain the radiator but just let the fluid come out as the parts were removed.
Don't forget to buy some replacement coolant as you will lose a gallon or so.
The airpump didn't need to be removed.
Clean the surface (on the block) well as mine had some of the old gasket stuck to it. (don't 'nick' the surface, gently remove the old material)
In addition to the part I would look at replacing your fan belt if it's due as you will need to take it off to get to the thermostat.
Some semi special tools require: Torx socket for the idler pulley and the thermostat (I think the size is "10").
Note: While I could reset the CEL (check engine light) I had some difficulty resetting the last P0128 code as I believe it is tied to an emissions algorithm. It eventually went away after a few days.
ref: https://mbworld.org/forums/glk-class...orn-p0128.html
04-26-2018, 06:42 PM
#4
Junior Member
Base on my recent fix, this code is surely a bad Thermostat that is stuck open.
It happened when car has roughly over 130km.
Maybe it is a good time to have your belt, and idlers all change
together and save $$ on labor, belt would have to come off
to get to the Thermo...be sure to get at least a Bosch part,
it's a no no for aftermarket parts.
It happened when car has roughly over 130km.
Maybe it is a good time to have your belt, and idlers all change
together and save $$ on labor, belt would have to come off
to get to the Thermo...be sure to get at least a Bosch part,
it's a no no for aftermarket parts.
