[Spun Crankhub]

Call me a noob or whatever for not searching, but I can't find the search option on my phone. Back to my question, what is this sensor mounted on the passenger side of the radiator on my 09 328i? Thanks!!!

[mike3000fl]

probably outside air temp

[BKV122]

Airbag maybe?

[triger716]

This is from the Bentley manual and might be what you're talking about.

N51 engines use a manganese oxide coated radiator that works to reduce ambient air ozone. This radiator uses an EAC (Environmental Air Catalyst) sensor to check that the special coated radiator if fitted to the car.

NOTE-

• The EAC sensor is hard wired to the radiator so that it cannot be disconnected. In the event of failure of the EAC sensor, it can be replaced once. If the EAC sensor fails again, it must always be replaced together with the radiator.
• The EAC sensor continuously transmits a signal to the engine control module. If an uncoated radiator without an EAC sensor is installed, the ECM will illuminate the check engine lamp.

I'm not sure what they are trying to say in the second sentence, but that is how it is written.

[jmen11]

Originally Posted by triger716

This is from the Bentley manual and might be what you're talking about.



I'm not sure what they are trying to say in the second sentence, but that is how it is written.

I believe it says if you have the wrong radiator installed you get a check engine light.

[triger716]

Originally Posted by jmen11

I believe it says if you have the wrong radiator installed you get a check engine light.

No. I mean this one. "This radiator uses an EAC (Environmental Air Catalyst) sensor to check that the special coated radiator if fitted to the car."

...to check that the special coated radiator if fitted to the car, doesn't exactly make sense to me. Do they mean is fitted to the car? So the only thing the sensor does is tell the car that the special coated radiator is in fact installed and not a different radiator without the coating?

[kar40980]

Sensor is only in sulev motors.
I transfored sensor into a after market radiator in my 08 328xi N51.
Because radiator was not manganese oxide coated it would not produce a correct reading and a dtc would set.(after about a week but never when below 40f)
That forced me to buy a much more expensive oem radiator.
Just a FYI incase anyone has to change radiators.

[puffer]

I got the 2AD8 code today on my N51. No SES light yet though. If all the sensor is doing is checking if the radiator is coated, does it matter if it malfunctions, since I know I have the right radiator (still the original). Can I just clear the code and forget about it?

I recently installed the AFE sealed intake. Could that somehow have caused the code?

[David1]

Do not touch it or it will cost you!

[puffer]

So my plan of ignoring it will not cost me?

[David1]

Does not interfere with how the car runs, but will keep setting codes. On the e46 cars you had to change the radiator to replace the sensor.

[Blackhawk36]

The radiator coating is part of the total emissions package. As Ozone in the air (a prime contributor to smog in the summer) passes through the radiator the coating converts it oxygen.

[Spun Crankhub]

Originally Posted by kar40980

Sensor is only in sulev motors.
I transfored sensor into a after market radiator in my 08 328xi N51.
Because radiator was not manganese oxide coated it would not produce a correct reading and a dtc would set.(after about a week but never when below 40f)
That forced me to buy a much more expensive oem radiator.
Just a FYI incase anyone has to change radiators.

^This. You cannot put the sensor on a non manganese radiator. Unfortunate that the radiator, even used runs in the mid to high $200's.