[opinion914]

Chasing a CEL that pops up weekly after clearing.
258F00. Outside Temperature Sensor Plausibility : Outside Temperature Not Plausible.
Odd thing #1; my outdoor temp reading in the dash is 100% functional and accurate.
Odd thing #2; when checking outside air temp via BimmerTool (Air Ambient Temp reading) I get a temperature that's waaayyy too high. When it's 80 deg outside BimmerTool is reading 145deg from somewhere and it's not the sensor that's reporting to the dash readout.

How many outdoor air temp sensors we have on the F30-F31's? I know of the one in the front lower wheel well area (in the intake duct on Msport cars) but there has to be another sensor giving this implausible readout of 145deg and triggering the CEL.

It's not the 'intake air temp sensor". That one I know about and it's functioning as designed.

The error code is within the "Engine" section if BimmerTool so I don't believe it's a cabin air temp sensor.

[opinion914]

..more simply:

Why is my OBD2 port temp reading one number (incorrect) and my dash temp reading another (correct) ?
It's not a C to F conversion thing.

[Enabled]

Freeze frame data for that BMW code may help here

[opinion914]

Thanks, Abel. During these issues the dash has always given me accurate outside air temps.
Odd, no?
It's 140deg outside according to the OBD2
80 degrees according to my dash. (Correct)

[Enabled]

Did you clear the codes yet?

When the system registers a code, it will give a recording of al the conditions and sensor data it read at the time of the error code. This is what the freezeframe is. It may be very important here.

For example, if the temp sensor is failing intermittently and goes short to ground, it will give a temporary -40deg or so, and then come back.


Unfortunately, in the case of aftermarket programs, I can't trust that what they programmed to display up there is even correct.

Bimmerlink has many glitches and bugs still.

[opinion914]

I have cleared the code, several times. It typically comes back within 200 miles.
Which program would get me the Freezeframe data? I have no Ista nor BMWtools.

[F32_Sierra]

Originally Posted by opinion914

I have cleared the code, several times. It typically comes back within 200 miles.
Which program would get me the Freezeframe data? I have no Ista nor BMWtools.

any OBD II scanner should be able to give you freeze frame data for that specific code due to that being a generic OBD II function.

Oreillys ot AutoZone should be able to scan it then ask for the freeze frame data for that specific code

[opinion914]

Originally Posted by F32_Sierra

any OBD II scanner should be able to give you freeze frame data for that specific code due to that being a generic OBD II function.

Oreillys ot AutoZone should be able to scan it then ask for the freeze frame data for that specific code

Thanks F32. I will run to a buddy w/ a Snap-On scanner and see about this Freeze Frame thingie. If that fails I'll check out AutoZone / AdvanceAuto.

-K

[Enabled]

Originally Posted by opinion914

Thanks F32. I will run to a buddy w/ a Snap-On scanner and see about this Freeze Frame thingie. If that fails I'll check out AutoZone / AdvanceAuto.

-K

Message me and we'll do it remotely over ENET if needed.

[Onizukachan]

Your hint is in the fact that it is OBD2 and throwing a code.
You aren’t going to be reading the temp sensor for the dash display (used to be under bumper on prior models, dunno where it is on f30) but rather you are reading what the DME is seeing from an engine sensor.

The under bumper has never been tied in to Dme on any prior model and I seriously doubt it is now either.

[opinion914]

Originally Posted by Onizukachan

Your hint is in the fact that it is OBD2 and throwing a code.
You aren’t going to be reading the temp sensor for the dash display (used to be under bumper on prior models, dunno where it is on f30) but rather you are reading what the DME is seeing from an engine sensor.

The under bumper has never been tied in to Dme on any prior model and I seriously doubt it is now either.

Interesting. Would you know where this engine-related air temp sensor may be on an N47?
My searches only point me to the one in the bumper, which is not the culprit as it's giving correct readings (dash).

[Enabled]

Good input

[Onizukachan]

This might help. N47 does have intake temp sensor… that’s how farkle was able to compare intercoolers.

[Onizukachan]

13627812741 Is the p/n if that helps you find it in real OEM

[opinion914]

Originally Posted by Enabled

Good input

Thanks. Except there are no issues w/ the dash display and no Kombi codes.
That article seems to suggest if the front bumper sensor was acting up it would impact the dash display as well.

It's got me scratching my head for sure.

[opinion914]

Originally Posted by Onizukachan

This might help. N47 does have intake temp sensor… that’s how farkle was able to compare intercoolers.

Thanks, Oni. But my air intake temps are fine and reading accurately. I too thought it would be that AIT sensor but my live data is reading correctly for that sensor....

[opinion914]

Looks as if the fault isn't constant but rather intermittent. The sensors were all reading correctly at idle this morning...

[Enabled]

I would collect more data about the fault conditions and guided by that info, I would replace a sensor.

Most likely the outdoor temperature sensor would be first. Since the output to the DME from cluster is adjusted via a software model, an intermittent failure would greatly influence how well the software model works.

I doubt it's the IAT.


I would also consider resetting the instrument cluster and/or updating it if it's on really old firmware, but this is a shot in the dark.

[Onizukachan]

Or unplug the cluster and plug it back in?

[Enabled]

Originally Posted by Onizukachan

Or unplug the cluster and plug it back in?

This would work for that purpose, yes!
It would be the same end goal as disconnecting battery ground for 1 minute, you'd still wipe the clock and trip odometer.


When/if we get a moment to remote in, I can see how old the cluster firmware is too.

[opinion914]

Originally Posted by Enabled

When/if we get a moment to remote in, I can see how old the cluster firmware is too.

Ready when you are. Does the CEL need to be present? Silly thing went off in its own.
Don't fret, it'll be back

How's the plug to the cluster accessed?

[Onizukachan]

Take off top two screws and lean it forwards. It’s on the back.


I figured if it had a gunky pin outputting corrupted temp info to DME that that might clear it up whilst resetting the cluster too. Though that info is probably on k bus, so shouldn’t really do anything but it never hurts to do the old unplug and plug back in.