orcaspi

IF YOU ARE REPACING THIS SENSOR i FOUND AN ESSY WAY TO REPLACE IT WITH OUT Taking everithing apart.

orcaspi

FOR THOSE NEW TO AUDI, I FOUND THE HARD WAY THAT IT SIMS EASY BUT MOST LILELY IS DIFICULT, HOW EVER IF YOU PUT SOME REASONING TO IT YOU MAY BE ABLE TO DOIT YOUR SELF JAJAJAJAJ. THE ESIY WAY TO CHANGE THIS SENSOR IS TO GO TOUGH THE PASSENGER SAID IF YOU SEE UNDER NEED THE GLOVE COMPARTMNET HAS A COVER. IF YOU GO TO THE CORNER YOU WILL SEE THAT THE COVER HAS A GRILL; MOVE THE COVER SOFTLY SO YOU DONT BRAKE IT AND INSERT YOU ARM TROUGH AND UP YOU WILL SEE AND BE ABLE TO TOUCH THE SENSOR, ONCE YOU TOUCH THE SENSOR JUST TURN IT AN IT WILL COME OFF. YOU MAY HAVE TO REQUIRED THE SERVICES OF YOU SMALL BROTHER FOR THIS SINCE THE SPACE IS SMALL. bUT IT WILL SAVE YOU TIME AND HEADAIQS. ALSO, I FOUND THAQT THE SYSTEM WORKS PERFECTLY WITHOUT IT AND MIND IS NOW IN REMITION IN OTHER WORDS I DID NOT PUT IT BACK. NOW I CAN USED THE AUTOMATIC TEMP CONTROL WITH OUT THE TEMPERATUE SHOWING -15 F* WHEN WE HAVE LIKE 98 F* HEAR IN MIAMI.IT IS WORKING FIND FOR ME. I HOPE THIS WILL HELP ANYONE AN DONT HAVE TO GO TROGHT HE PAIN I WENT TROUGH JAJAJAJJAJ

hayward0709

This was verified by me on my 2000 audi a4 1.8T. I had the exact same symptoms for months and read this yesterday. I skipped the ambient temp sensor, ordered the fresh air duct sensor and installed it after work. I drove it about 250 mi. today on a trip and had no problems the whole way. I think it's safe to say, problem solved. Thank you for saving me both time and money.

orakay

Hi,
I have almost the same problem. Mine is an Audi A4 1.8 Quattro 2001. Temperature drops down to -50 degrees C and A/C stops working. I have already changed the ambient temperature sensor but didn't solve the problem. Now I am planning to change the fresh air intake sensor BUT,
I have played with the on board diagnostics and
"58 Temperature in deg C, from Fresh Air Intake Duct Temperature Sensor (G 89)"
returns logical values, as well as
"59 Temperature in deg C, from Outside Air (Ambient) Temperature Sensor (G 17), front".
Only the erroneous reading is at:
"47 Outside (ambient) temperature, unfiltered, (internal software, in deg C)"
In this case is it still logical to change the sensor?
I think that problem is originating from an error in either climatronics unit or the instrument panel.

I would appreciate any comments please...

echo_s4

I finally got around to changing my fresh air intake duct temperature sensor (G89 - p/n 4A0-820-539-A). Indeed, the climate control diagnostics showed that this part (code 58) had been returning negative values before the replacement. Now it's showing normal temperatures. Thanks to this message board for the help.

It's about a one-hour job if you remove the glovebox (which I did). But I think you might be able to replace the sensor without removing the glovebox, as orcaspi mentioned, in which case it would be a 5-minute job. You just need to know what to feel for, so I've attached some pictures to show what it looks like.

Tips:
The first picture shows how the connector-sensor assembly is mounted to the air duct near the passenger side firewall. The camera was pointed upward behind the glovebox. To get a feel for the orientation, I drew axes that follow the edges of the connector. In order to disconnect the connector-sensor assembly from the air duct, rotate it 90 degrees and gently pull it out.

The second picture shows the connector-sensor assembly dangling by the wires. Pinch the two metal clips on the sides of the connector to free the sensor so you can pull it off.

The third picture shows the old and new sensors side-by-side.

CSBM5

Thanks very much for your post and to others in this thread. It did actually take maybe 10 minutes to do this by just reaching up behind the glovebox; however, what made that possible was removing the plastic panels and cabin air filter under the hood. Then you can see the sensor sticking out into the air duct. Having one person provide torque to loosen the sensor from that side while the second one (with the thinnest hands/arms) reaching under the dash and rotating also, it easily pops out, and then the connector can be disconnected and connected to the replacement sensor.

Reinstalling, the person under the hood can guide it into position as it is poked through the hole by the other person inside. Then both rotate it into position. Done.

We took this time to clean out the two drains in the cowl also. Removed the battery and battery tray, vacuumed out the mess in there and in the drains, then used a coat hanger wire to ensure the drains were free.

birdstheword909

04' A4 AVANT . would this affect A/C output temperatures ? . I just noticed that my dash display is way off , it shows negative temps when its 106 out here in So Cal .

CSBM5

Yes. This is why we replaced it since in 105F weather recently the compressor would be turned off which coincided with the dash display showing something like -40F. Sucks to be in 105F weather and have a perfectly fine A/C being abducted by a measly sensor.

birdstheword909

ok , so i just went ahead and looked down inside where the blower motor is and i saw the sensor sticking out . Correct me if im wrong but this sensor reads temps. based on voltage ( my guess static in the incoming air temp ) . So i thought to myself " hey , maybe if i clean it it will read better " so i cleaned it with some MAF sensor cleaner and a small piece of shop towel . IT WORKED ! , I only did this as a temporary solution , tomorrow i get my new sensor . On another note I noticed when the car is not in motion the A/C compressor sometimes wont compress and the the coolant temp gauge will start to rise . As soon as i turn off the A/C coolant temps. go back to normal . I also noticed there is a loud hum - vibration noise coming from the secondary fan when i turn on the A/C . i think the A/C clutch gets stuck on engaged mode and puts too much stress on the engine cooling system . Also I just did the ECS timing belt kit ,Coolant flange , cam chain tensioner and top end gaskets .

birdstheword909

PN 1K0907543A is for 2004.5 , the sensor i bought is manufactured by VEMO and did not fit my electrical connector . 4A0820539A WILL NOT fit 2004.5