Bruce Hubbard

Fitted to the W212 E250 M274 engine
Charge air temperature sensor
Mercedes part number 276905000

Unplug the cable
To remove the sensor lift the locking tab slightly with a screwdriver
and at the same time with an 8mm spanner twist it anticlockwise approx quarter to half turn
then wiggle it and pull it out of the pipe fitting (pipe that feeds the throttle assembly)

It is a thermistor and I measured the resistance at room temperature to be 10.3k ohms
I cleaned it with Liqui Moly Air Flow Sensor Cleaner
Check the o-ring seal
To refit the sensor insert it and twist clockwise until it click locks
You should be able to turn it by hand now that it has been out
Plug the cable back in

S-Prihadi

Let me assist you in making the instruction better, as there are 2 locking latches on the thermistor which need to be disengaged from the female port.

This is from the aftercooler of M276 3.0 Turbo. Which uses the same sensor, so the method is the same.

At a glance the thermistor seems to not have any sort of locking mechanism when seated, if working space is as tight as mine.



.
With the aftercooler out, it is easy to see the hidden 3mm high protrusion on the female port. I don't know what to call that protrusion, sorry




These the the 2 latches I speak of, where the counter clockwise turning of the sensor is to clear this latch.



Happy digging them sensors......

Bruce Hubbard

Excellent additional detail
The protrusion and ramp I called the locking mechanism which stops the sensor from rotating and vibrating loose

JS NZ

Thanks everyone, I found it busted so will replace, It is on my SLS though not an E250. Would the data off this sensor also be used for the a reference etc for the radiator temp. When motionless with engine on, temp will go up to 130 celsius then drop down in 5 degrees increments which I put down to software.

BTW if anyone was following my gearbox saga it looks like the issue was just earthstraps loose so I now have a used gearbox for sale which is probably fine.