Error code: 48FE intake air temperature sensor, plausibility

rav · Post by **rav** » Tue Sep 05, 2023 8:07 pm

Hi All,

Any ideas on this particular error code which I am now consistently getting: "48FE intake air temperature sensor, plausibility" on the 3.0d N57 engine? There are no engine management lights on the dashboard.

The car seems to hesitate when starting from standstill and also when trying to accelerate. It also feels like there is less power and fuel economy may have gone down. Just listing all the current observations which may or may not be related to the fault code

X5Sport · Post by **X5Sport** » Tue Sep 05, 2023 8:54 pm

48FE means that after at least an hour of cooling there is too much difference between MAF temp and after intercooler air temp. One of the sensors might be failing, and most likely to be a sensor failure on the charge air side - airflow after the intercooler and before the MAF/Throttle.

On my E71 (same engine) it’s item 15 here: https://www.realoem.com/bmw/enUS/showpa ... Id=11_4433

Other sensors involved are on this slide: https://www.realoem.com/bmw/enUS/showpa ... Id=11_4590

The system is just saying that the data it’s getting doesn’t make sense as one of the readings is out of the expected range.

Use the last 7 of your VIN on RealOEM (Serial Number) to pull up your variant in case there are differences. You’ll find the intake manifold slides in the ‘Engine’ group.

rav · Post by **rav** » Tue Sep 05, 2023 10:00 pm

Thanks. I will have look at the w/e to assess if this is something I can do. If so, I will order the two sensors - they seem to be the same as on your engine as you said.

rav · Post by **rav** » Fri Oct 20, 2023 1:54 pm

Just an update on my earlier post.

I replaced both the Air intake temperature sensor (13628519445) and the Intake manifold pressure sensor (13627804742 - Sensor, charge-air pressure) - fairly easy to do once you know where they are. This seems to have got rid of the hesitation when trying to take off from standstill and also when trying to accelerate to a large extent so good news here. It removed the fault codes that I had.

However, during a long trip (around 400 miles), I had the engine light flash briefly indicating reduced power mode but it disappeared and everything seemed fine. Checking the fault codes, I got new ones now (maybe related):

48E0: 48E0 ambient pressure sensor (installed in the control unit), plausibility
48EC: 48EC pressure sensors, plausibility

Also got the below ones:
4B81: 4B81 Exhaust gas re-circulation rate control, control deviation

Electronic transmission control:
CF32: Message (Operation gear selector LIN, 2h) for (EGS_EL, PT-CAN) of (GWS, LIN)

Gear selector switch:
E095: Message (Anzeige_Getriebedaten_LIN, 0x02)

Any thoughts welcome.

X5Sport · Post by **X5Sport** » Fri Oct 20, 2023 3:04 pm

48EC - pressure difference between the charge air pressure (turbo out), exhaust gas pressure sensor (before turbo) and ambient pressure sensor is more than 60mbar. Could indicate an overloaded DPF.

48E0 - is linked to above. Pressure data between the sensors exceeds 150mbar (should be no more than 130mbar).

If the codes are still present then that suggests either a sensor failure or the DPF needs looking at. You could do with getting the ash and soot loads checked to see if the car is regenerating properly.

CF32 appears to be connected to missing wheel speed data from the front left wheel, but it’s also used for what you’ve reported. No data showing against that version.

E095 - haven’t found anything useful. Might be an issue with the shifter switch unit itself.

If you clear the codes, do they come back?

rav · Post by **rav** » Sun Nov 19, 2023 3:18 pm

The code "48EC" does come back when cleared. Is this not referring to the pressure sensor inside the ECU? Not sure how that would show up as it seemed to be triggered when I changed Intake manifold pressure sensor. I did use a non-OEM part so maybe this is impacting in some way. Might try to clean the original one and and replace it to check.

I now also have the following codes showing up and and engine warning light that before flashed up and disappeared occasionally but now sticking:

4C9F: exhaust gas recirculation valve, plausibility
4C9E: exhaust gas recirculation valve, plausibility

The EGR was checked and found to be clean last year but I guess it may need replacing.

Can't seem to go on a trip without having the engine warning light come up at some point

Leslie · Post by **Leslie** » Sun Nov 19, 2023 9:02 pm

Those codes are for egr by look of it see below,wear in egr valve

https://www.youtube.com/watch?v=pVzJegWLbeQ

rav · Post by **rav** » Wed Dec 27, 2023 1:33 pm

The hesitation on the car started getting worse again so I checked the new intake manifold pressure sensor and it seemed a little sooty even though it had only been in for a couple months. I guess this indicates and issue with the EGR valve getting stuck. I cleaned the original part that I had kept and and put this one in - it seems to have cleared the 48E0 and 48EC which may have been caused by the aftermarket part. In fact, All EGR codes are clear for now at least but I suspect the 4C9F and 4C9E will return in due course.

The link in the above post to clean the EGR is great but I am not sure where the EGR is positioned in the engine bay - I could not find any video of its removal. Is anyone able to point me in the right direction?

marti · Post by **marti** » Thu Dec 28, 2023 12:18 pm

https://www.realoem.com/bmw/enUS/showpa ... Id=11_3869

Number 1 is the EGR,,,easy to remove

X5Sport · Post by **X5Sport** » Thu Dec 28, 2023 1:01 pm

That’s for the M57 engine. OP reports an N57 engine which is EU4 and different. Part #3 on this slide for the N57 fitted to a 30D. If it’s a 40D (same engine) then it’s still the same part.

https://www.realoem.com/bmw/enUS/showpa ... Id=11_4258

marti · Post by **marti** » Sat Dec 30, 2023 12:35 pm

My bad

This may help: https://www.youtube.com/watch?v=QweSrqIqz2k

X5Sport · Post by **X5Sport** » Sat Dec 30, 2023 2:13 pm

The M57 is a far simpler beast…sigh.

marti · Post by **marti** » Sun Dec 31, 2023 1:37 pm

X5Sport wrote: ↑Sat Dec 30, 2023 2:13 pm The M57 is a far simpler beast…sigh.

Indeed it is.....

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