I just read the ecu codes on my 90TII and am getting three codes ( 9 -water thermosensor, 15 - oxygen sensor, and 40 - auxilary port valve).



I think the water thermosensor is the sensor that goes in the top of the radiator. But i am not sure.



I have no idea what the auxilary port code is. I probably sound pretty dumb but what the hell do i do for this.



Thanks

The water temp sensor *should* be on the bottom of the radiator,not the coolant level sensor on the top.

O2 sensor you understand, the wire to it is small and often gets broken.

APV is the valve that sends air to the cat, and in an S4, controls the 6-ports.

the water thermosensor is in the rear of the water pump housing.



code 40 is for an na, its the 6 port valve solenoid valve



mike

thanks a lot guys, but i pulled code 40 off of my ecu. i will check again maybe i read it wrong.



thanks

Well time for an update. I fixed the code 15 and code 9 but for some reason i am still getting code 40 and now code 2 which is for the crank angle sensor (ne sensor). I don't understand why that would come up all of a sudden. I have not driven the car since i pulled the codes earlier so why would this just come up.

those ecu's can only hold a couple of codes, that and they dont seem to be consistant about it



mike