Gool

hey all,

Driving my 2008 S550 today the engine light turns on.
engine scan shows p0071 (ambient air temp sensor
range performance)

the temp on the dash reads +7c
then I checked what the reading on the dash was in my slk and it was +1

Im having a hard time finding the air temp sensor on the bumper.
there is a spot for it near the left fog lamp but no sensor or harness or plug?
does the w221 read off the map sensor for ambient temp?

thanks

mstrbenztech

No, it does read the ambient temp sensor. It is located in the bumper and can be hard to locate. A lot if times water will enter the sensor and give a false reading. Another common problem is the sensor will become detached from its mounting and may rest closer to the engine also giving a false reading

Gool

thanks. thats what thought.
i have changed them before on c class and e class even w220 but not on w221
I can see on the bumper where it mounts.
I have pulled the front bumper to find the sensor thinking it had fell behind but like i said there is no trace of it being there.
not even a harness or plug.
weird....

is there another spot?

MagCL

It should be there, above the left fog light but closer to the licence plate.

eichstam

I had the P0071 error message and ordered a new sensor. The new sensor arrived this week and I installed it today. My sensor was detached from the mount when I removed the front bottom engine cover. I am attaching a few pictures.

asdqwe33w

do you guys know where to order the part? Is Rock auto a good place to order part?

alx

You want an oem sensor. Rockauto are mostly not oem parts. Parts.com is one of the cheaper sources for oem parts.

asdqwe33w

do you guys where I can get the oem part ?

mercedesbenzs55

Alx told you in the above post. Parts.com = Cheapest OEM parts.

xpl0sive

www.oediscountparts.com is a good site for actual OEM parts with an OEM catalogue

asdqwe33w

where did you order the parts from? (eichstam)