BMw z4 e89 3.0i SDrive AUC Sensor Replacement Advice

Varixto

Varixto

Member
Hi,
I have an AUC error code so I have just bought an OEM replacement sensor and would like to replace it myself. The sensor seems to be placed under the scuttle panel, where the small grill is (ie: passenger's side if you look at the car from the front).
Is there a way to replace it that doesn't involve removing the scuttle panel and the wiper arm(s)? I have a wiper arm puller, etc... but if there was a shortcut to avoid the hassle, I would be very grateful if you could share it.
Thanks in advance!
 
No you need to remove the scuttle panel / wiper arm..it’s a common failure item..
 
Varixto said:
flybobbie said:
What's AUC?
Click to expand...
Automatic Air Recirculation Sensor.
Click to expand...

It actually sniffs the nitrogen oxide hydro carbon and carbon monoxide pollutants and send a signal to the HVAC to close the fresh air intake… :thumbsup:
 
Well i would say never worked on my car.
Having said that i leave it on recirculation.
Still get stinks from outside.
 
flybobbie said:
Well i would say never worked on my car.
Having said that i leave it on recirculation.
Still get stinks from outside.
Click to expand...

Usually fault codes up when it’s faulty.. :thumbsup:

I have it on fresh air…but..since I drive almost entirely roof down it’s a bit academic.. :tumbleweed:
 
My 2.5 2003 E85 has the AUC sensor under the engine bay threshold cover and is clipped above the radiator under the threshold so that has to be removed to access the sensor. Its not that important and last time I looked BMW wanted around £70 for a new one. I did try fitting a new sensor inside the plastic housing box, obtained the sensor from an electronics supplier for £17. Its a small round red sensor used in equipment to detect fumes so not just a BMW sensor. It didn't last and got a code for it again so ignore it now. Stands to reason the AUC sensor is mounted at the front so it picks up fumes in standing traffic.
https://www.realoem.com/bmw/en/showparts?id=BT32-EUR-05-2003-E85-BMW-Z4_25i&diagId=64_1265
 
This is a general comment on this issue, as I've already spoken to Varixto about this.

With certain fault codes, and with certain coding apps (Carly in this case, possibly others), if the fault code is not cleared properly then it wont allow you to code other features. A lot of these features of the car (well 99% actually) are all linked together, not just by the CanBus and LinBus systems, but they rely on each other for certain inputs. Without these inputs they wont allow you to code them as it's in a fault condition.

I've attached a screenshot from the manual to show it's location :thumbsup:

Description from the manual...

Sensor for automatic air recirculation control

The AUC sensor is fitted on the microfilter compartment. The AUC sensor detects the following pollutant emissions from spark-ignition and diesel engines:

Hydrocarbons (CH )
carbon monoxide (CO)
Nitrogen oxides (nitrogen monoxide NO, nitrogen dioxide NO2)
The junction box supplies the AUC sensor with voltage. The junction box electronics evaluate the data of the AUC sensor. The junction box electronics unit transmits relevant data to the IHKA control panel (via the K‐CAN).

Hope that helps :thumbsup:
 

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AnubisZed said:
This is a general comment on this issue, as I've already spoken to Varixto about this.

With certain fault codes, and with certain coding apps (Carly in this case, possibly others), if the fault code is not cleared properly then it wont allow you to code other features. A lot of these features of the car (well 99% actually) are all linked together, not just by the CanBus and LinBus systems, but they rely on each other for certain inputs. Without these inputs they wont allow you to code them as it's in a fault condition.

I've attached a screenshot from the manual to show it's location :thumbsup:

Description from the manual...

Sensor for automatic air recirculation control

The AUC sensor is fitted on the microfilter compartment. The AUC sensor detects the following pollutant emissions from spark-ignition and diesel engines:

Hydrocarbons (CH )
carbon monoxide (CO)
Nitrogen oxides (nitrogen monoxide NO, nitrogen dioxide NO2)
The junction box supplies the AUC sensor with voltage. The junction box electronics evaluate the data of the AUC sensor. The junction box electronics unit transmits relevant data to the IHKA control panel (via the K‐CAN).

Hope that helps :thumbsup:
Click to expand...

The RHD AUC is on the opposite side of the engine bay..that pic only applies to LHD :thumbsup:
 
I have replaced my AUC sensor recently. I did not need to remove the wiper. Once you have unclipped the plastic cover there is plenty of room to get your hand in there and unclip / replace it.
 
jonkoxe11 said:
I have replaced my AUC sensor recently. I did not need to remove the wiper. Once you have unclipped the plastic cover there is plenty of room to get your hand in there and unclip / replace it.
Click to expand...
Thank you for your reply. That's great to hear! Did you remove all the clips or just the ones on the passenger side?
 
Just be careful this time of year due to brittle plastic as it’s cold. I replaced mine this time a year ago and broke the clips that hold the cowling in place. As it was on the cowling itself I had to buy a new one at £70.
 
Reamesy said:
Just be careful this time of year due to brittle plastic as it’s cold. I replaced mine this time a year ago and broke the clips that hold the cowling in place. As it was on the cowling itself I had to buy a new one at £70.
Click to expand...
:thumbsup:
 
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