external temp
Thread Starter
Super Member
Joined: May 2011
Posts: 883
Likes: 72
From: Vancouver
2018 e63s edition 1
external temp
This is probably a silly question but does whatever is used to measure the external temp have anything to do with how the car runs or anything other than just the outside temp reading? The reason I ask is because for whatever reason my external temp is way off, it's over by a good 15C degrees and my car has been running kind of weird in this mid 30C heat that we've been having. A friend with a diesel truck mentioned that whatever projects the external temp for his truck also controlled something else.
Super Member
Joined: Feb 2012
Posts: 620
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From: Sacramento, CA
'09 C63
If you take a look in the lower front grill on the driver's side, you'll notice that one of the vents has a full plastic piece (on pre-face lifted models) cover and in the top corner is a small protrusion; that's the ambient temperature reader.
It's relatively in close proximity with the engine so temps tend to be a bit off. I've had it one time where it broke off back inside the engine bay and I was getting ridiculous temperature readings...scared me for a moment.
But to answer your question, yes. I get in accurate readings all the time.
It's relatively in close proximity with the engine so temps tend to be a bit off. I've had it one time where it broke off back inside the engine bay and I was getting ridiculous temperature readings...scared me for a moment.
But to answer your question, yes. I get in accurate readings all the time.
Junior Member
Joined: Apr 2015
Posts: 55
Likes: 1
2009 C63 AMG
My external temp usually reads pretty high as well, but it doesn't affect how the car runs, it has its own intake air temp sensor. That said it will definitely run better in cool, dense air than hot air.
MBWorld Fanatic!
Joined: Feb 2010
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2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
Check to make sure the temp sensor has not been pushed in and fallen behind the bumper cover. If this happens the sensor will read high because of the engine heat trapped behind the bumper cover. On the FL the sensor is in the same lower grill on the drivers side and the sensor is in the lower left corner looking at the grill.
Thread Starter
Super Member
Joined: May 2011
Posts: 883
Likes: 72
From: Vancouver
2018 e63s edition 1
Fair enough, I don't care that it doesn't read accurately, I just wanted to make sure that whatever read the exterior temp wasn't related to something like monitoring oil/coolant/etc temperature.
But at least now I know why it might be so far off, I'll have a look. So it's something that can full in behind the bumper cover but can easily be put back in place?
But at least now I know why it might be so far off, I'll have a look. So it's something that can full in behind the bumper cover but can easily be put back in place?
MBWorld Fanatic!
Joined: Feb 2010
Posts: 5,648
Likes: 484
2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
Yes, the sensor is held in place by clips and during washing it is possible to push it inside the bumper cover, especially if it is not clipped in place properly. It may require removing the bumper to put it back in place, if it has fallen behind the cover, but possibly it can be restored if the front belly pan is removed.
