AudiSport4000

Sorry to repost this, but its about that coolant sensor fault code that my 4ktq has been throwing. I dont recall the number it was, as the Bentley is in the car.
Anyhow, the only coolant sensors that are hooked up to the ECU harness are the 2 pin type sensors located by the PS pump. I assume these are the sensors that I should be checking? Steve mentioned something about the MFTS having something to do with the ECU enrichment of some sorts. But with the MFTS plug not being in the "red" harness I used, I dont know if thats the problem. This is the first time Ive gotten the code since the swap has been done.

I assume its one of those 2 silly pin sensors. Also, yes, I need to check the specs of each and the wiring inbetween the ECU. What should those sensors read? I have also switched the wires from each one, but no difference was noticed.

audiqv8

So I'm assuming that you took a 10v turbo engine and stuck it into a 4000 quattro.
Did you also switch the wiring harness and ECU from the turbo engine?

Below images show where each sensor is located.

<img src="http://www.sjmautotechnik.com/trouble_shooting/ecupic/ecutemp.jpg">

<img src="http://www.sjmautotechnik.com/trouble_shooting/ecupic/airtemp2.jpg">

AudiSport4000

I switched to the MAC11 ECU and harness. I did change both of the smaller "pin" coolant sensors a while back, but thats no to say they are still good.
Was just curious as to what temp sensor the ECU is telling me is bad, or has the fault.

SteveAngry

It sends a signal to the Auto check, Temp gauge and ECU IIRC.

What I don't know is if the MFTS wigs out, does it trigger a fault code. I know yours is completely missing...

Mine went bad(temp gauge no workie) but there was no fault code.

I would remove the ISV and ECU sensors, measure them cold, warm and hot and see that the values are similar. One might be bad.

If they are similar readings then I would confirm your wiring isn't fubared.

Steve
Michigan