seltech

Also i just noticed my check engine light came on for a second then went off, I checked the codes and had 2312 again which is the ETC sensor.. I just replaced the ETC sensor last night too.. this is starting to suck...

seltech

Ok, I played with the thermal switch plug and i did get both low speed and high speed fans to come one by jumping it ( I had the relay out for low speed fans on the fuse box lol )

Going to get a new thermal switch this afternoon to see if it cures the issue.

I'll report back with my findings, thanks for your input guys!

Lago Blue

Good question, I suspect the fan speeds are a motor function, simply activated by the switch. Is your wiring good, switch to motor. Can you apply power directly at the fan to test it?

maineman

When you go to replace the switch ,have the new switch ready to install and as soon as you have the old one out install the new one. Have a catch pan under the car to catch the little amount of fluid that comes out.This way you shouldn't introduce any air into the system. After getting the new sensor in top off the coolant.
I would bet that if you hooked a multi meter to the old switch you would find that you have continuity between the blades as would indicate a closed circuit ,hence the fan running.
AUDI,what a machine...............
good luck

seltech

Thanks guys,replaced the thermal switch and the fans are running correctly now! I'm super happy about it, on my ride home the temp gauge was smack dab in the middle which i think is perfect right?

After about 20 min of driving i got the check engine light again. i checked the codes and it was 2331 and 2341 which is oxygen sensor control 1 and oxygen sensor control 2

I'm assuming i've never seen the codes before because the engine temp was never high enough for the ecu to switch over the fuel maps and use the o2 sensors to calculate fuel?

Now my next question lol. Are the sensors themselves bad? or is it something else. I see other codes that relate to the o2 sensors in the DTC list, so i'm wondering if my problem might be something else then the actual o2 sensors?

200k miles and the o2's are probably stock

hubturn

I just replaced o2 sensors and am still throwing o2 codes. Next step is a Fluke 88-V multimeter ($300) to run all the tests Bentleys says to check this out. I'd like to know how this goes for you. Driving me crazy.

seltech

did you have the same codes as me hub? 2331 and 2341?

I know before I bought my 90 it sat for some time, and mice seem to like the intake manifold lol. I have a chewed wire up there from it, which reminds me I need to fix that lol. its the wire that runs next to the driver side intake runners, goes by the knock sensor and seems to land near the ac compressor somewhere, cant really tell where though.

Where did you purchase your o2's from? any places got them for cheaper then 70$ each?

maineman

http://www.europartsdirect.com/

If they are original then they are way past due to be replaced.

You may have a vacuum leak also.

hubturn

I bought them off Amazon, direct fit bosch, meaning no cutting and splicing, and paid about $70 each. I bought the same ones that Blau sells. I have a 95 Cab and my Ross-Tech vag-com codes are 554 and 537 adaptation limit surpassed. Bently says to check the wiring, the fuel system and if not either(thanks for the couple of days of work!) then it's the ECM. I need a really good multimeter anyway and a crappy needle type ohm meter could wreck the ECM by imputting too much voltage in the system. I have the 94-95 Audi Cabriolet service manual for Electrical Wiring and it clearly states, Fluke 83 digital multimeter, 10 Megaohm input impedence, + or - .3% DC voltage accuracy. The critical item is the 10 Meg ohm impedence to not fry your computers, like the ECM. Any good, accurate, 10 meg ohm multimeter will do.

seltech

3 digit codes with a 5 digit? I thought our cars gave out 4 digit codes with a 4 digit as maximum?

adaptation limit surpassed sounds like your long term fuel trims + short term fuel trims have maxed the ecu's allowed limits for total fuel compensation. could be the sign of a bad fuel pump or injectors not flowing like they should, I would lean towards pump first since that woudl affect all cylinders. Even a bad fuel pressure regulator could be the culprit or fuel filter thats clogged. might be worth checking before you start digging around deep.