Hi there in the mk4 section, I'm normally in the mk3 bit but have a mate with some issues with his Audi 18t
I scanned it and got codes
17704, P1296-35-00, error in mapped cooling system (usually temp sensor or thermostat)
16804, P0420-35-00, catalyst system bank 1: efficiency below threshold
I cleared them and we went for a drive round, where I noticed the temp gauge had gone right down, and when stopped would creep back up, also the cooling fan seems to run all the time, and oil temp not coming up very quick but was moving up.
He's changed temp sensor but still the same, so could it be the thermostat? I'm assuming the oil temp isn't rising very much because the engine temp isn't able to increase when driving cos air flow and fans running,
Could it also be the cooling fan sensor? Wouldn't it throw up a code? If the stat is stuck open would it also engage the fan?
The same codes came back, so what does the second code mean? Is the cat on its way out?
Sorry for noob questions, but not sure how to search this fault! Need to learn cos hoping to have a 18t in my mk3 by end of they year!
