CEL code P0642 & P2004

[tmqv34]

anyone know what these codes are.

P0642 Sensor A Reference Voltage Circuit Low

p2004 Intake Manf Runner Ctrl Stuck Open bank1 a


I'm pretty dumb when it comes to stuff like Voltage circuit low and ctrl stuck open etc.? shed some light for me.

Thanks in advance.
Peter Pan

[dave405nyc]

i had the p0642 error on my car...went away by itself after 3 hours... i think it has something to do with the knock sensor, an audi tech told me to use better quality gas (exxon/mobile sucks, which was what i was using). that code hasnt come up since then!

[cstarky15]

2004 code is a common thing. What year is your car and how many miles? Mine was covered under warranty. It is the flap in the intake manifold that lets in air or doesn't depending on what the car needs. I was getting 26ish mpg then got it fixed and am geting 32ish mpg mixed.

[tmqv34]

2006 a4 2.0t quattro with 64,xxx miles. I opened my intake and found a bunch of dust covering the filter. I cleaned and and did another check code with my actron and no codes show up =\. Im wondering if I fixed it. but I believe it is the flap because like you said about the gas issue. I'm getting less MPG

[cstarky15]

I would go and see if a local shop, not stealership can fix the flap for less. You have double my mileage and that would be why mine was covered. There is a thread about common issues with the 2.0 and possibly the codes that go along with ti. if you search you should be able to find it but i can't remember what it is called!