Strange problems with my S3

[Epforced]

First threadcreation, yay!

So I have searched the forums for an answer but I found nothing.
I have a strange problem with my car. It's an S3 -02 facelift.

Started with a problem with warm starts and engine light was on (CODE 17704). Swapped the thermostat for a non-genuine and the temp sensor for a genuine of ebay and after that my temp gauge will sit just next to 90 degrees whatever the weather is like, between 80-90 on the needle. If I'm in town the needle will reach 90 some times. I then changed the thermostat for a genuine one thinking it was because of it opening too soon.
Now my thermostat pipe is cold during driving, it's not opening too soon.

Both vag-com and climate control show around 75 celcius no matter what the weather is like. It wil reach that temp quickly and stay there except if I drive it really hard. Climate control has no problems heating.

I just realized there is oil temp also in the climate control and that show around 60-70 during cruising.

My primary thought is that the temp sensor i broken but not so broken that it sends totally wacky numbers to the ECU. Or that somewhere else there is a problem.

Please help me!

 

[auditech12]

Hi Epforced.

You have a MAP Controlled Cooling Fault. Your looking at either you (G62) Coolant Temp Sensor or Thermostat.

Given the fact you have not mentioned any over heating issue & your've already replaced the thermostsat anyway i'd suggest the Coolant Temperature Sensor (G62).
If it's a Black sensor just replace it no questions asked, they've superceeded to Green sensors for many years now.

Have fun.

 

[Epforced]

But I have a green one which I also replaced. That's why I'm confused. Can it be broken but don't throw a code?

 

[auditech12]

But I have a green one which I also replaced. That's why I'm confused. Can it be broken but don't throw a code?

You didn't mention you changed the ECT, that changes everything. ECT's don't always throw codes....BUT, You said in you first post you had code #17704.

You have a Grenn 4pin ECT, x2 pins are for the Gauge & x2 Pins are for the ECU.
I dont have a wire diagram, BUT. It would be wise to check the wires & carry out tests if you know how. )Check Voltage, Resistance & for a Voltage Drop.) Otherwise if you have spare coin or a spare G62 sensor fit another.... Check the engine earth points also jsut to be certain.

If that doesnt fix then your looking at a wire or a ECU issue.

 

[Epforced]

You didn't mention you changed the ECT, that changes everything. ECT's don't always throw codes....BUT, You said in you first post you had code #17704.

You have a Grenn 4pin ECT, x2 pins are for the Gauge & x2 Pins are for the ECU.
I dont have a wire diagram, BUT. It would be wise to check the wires & carry out tests if you know how. )Check Voltage, Resistance & for a Voltage Drop.) Otherwise if you have spare coin or a spare G62 sensor fit another.... Check the engine earth points also jsut to be certain.

If that doesnt fix then your looking at a wire or a ECU issue.

I did mention it, but whatever
Could it be that the ECT is faulty because it sends differnet values and the ECU then sets a pre-determined map?
I have seen through vag-com/climate control that the number there reaches 70 before the needle even begins to move.

 

[auditech12]

You DID!

YES, If the ECT "open circuits" the car will run off a pre-determined (Basic) MAP. It would/Should also store a code too.

This sensor you got from ebay is definitely the real deal? It's very possible it's faulty. Check its resistance....

In my 10 years of mechanics I've never come across a ECT wire fault....But never say never.
Check for Voltage to the sensor (5 volts). After this you start to get more serious if you find no fault.....

 

[Epforced]

You DID!

YES, If the ECT "open circuits" the car will run off a pre-determined (Basic) MAP. It would/Should also store a code too.

This sensor you got from ebay is definitely the real deal? It's very possible it's faulty. Check its resistance....

In my 10 years of mechanics I've never come across a ECT wire fault....But never say never.
Check for Voltage to the sensor (5 volts). After this you start to get more serious if you find no fault.....

So, a faulty ECT can cause the car to run at 75 degrees?
I Will check wiring tomorrow. it has been like this for a pretty long time since I was in contact with my local Audi dealership and they told me it was fine.

 

[auditech12]

Sure can, the ECT is what controls the gauge.....

They wouldv'e put the scanner on it. No faults & said it's OK. If your lucky they may've read "Live Data".

Are you actually having any running issues? High fuel consumption? Or is the EML coming on with the low temp readout & thats it?

 

[Epforced]

Sure can, the ECT is what controls the gauge.....

They wouldv'e put the scanner on it. No faults & said it's OK. If your lucky they may've read "Live Data".

Are you actually having any running issues? High fuel consumption? Or is the EML coming on with the low temp readout & thats it?

i justed talked to them, I now suspect they didnt know about it.
I have no running issues at all. Normal consumption, no codes, no lights in dash. Just that the needle stays just to the left of 90 on the dash.

 

[s3dave]

60 -70 running temp on oil is way off to mate...it should be alot hotter

 

[Epforced]

Sure can, the ECT is what controls the gauge.....

They wouldv'e put the scanner on it. No faults & said it's OK. If your lucky they may've read "Live Data".

Are you actually having any running issues? High fuel consumption? Or is the EML coming on with the low temp readout & thats it?

So I checked the resistance of the g62 and it showed 270 ohm on terminal 1 & 2 and 580 ohm on 3 & 4. Aircon showed around 60 degrees celsius when we took the test. Any thoughts?
I know you can check the gauge but it seems there is a fair chance of damaging the ecu?

60 -70 running temp on oil is way off to mate...it should be alot hotter

Are you sure? this is the reading from channel 51 on air con. this would be resting oil and a bit less than actual engine oil temp?

 

[Epforced]

Hasn't anyone ever seen this type of problem before?

Pretty gutted right now, a problem I can't fix and my windshield cracked today