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Hi all,

Having had my RS6 C5 for approximately 1 week I noticed the emissions lamp suddenly became lit. At first I thought it may have been because the petrol pump guy had put 95 RON petrol in. I waited until the tank was fairly empty and made sure it was filled up with Super. I borrowed a mates Elm 327 OBD code reader and reset the light.

However, after another few days the lamp again came on. This time I analysed the codes and took the attached screen shot.

Can anyone assist with likely causes of the reported problems?

I was tempted to take it to Audi here in the middle east but want to avoid the "lets change and charge you for 10 parts" situation when I had a similar problem with my Carrera 4.

Any assistance greatly appreciated.

Gary

I'm betting MAFs not seated correctly. Possibly a deteriorated o-ring given where you are.

Or simply bad MAFs.

Could be bad lambda sensors but more likely the MAFs.

Can your obd2 reader do live readings? If so see what g/s the MAFs are reading.

Ho there, i had a similar problem, it was down to me not using the car enough and the MAFs weren't working properly. My garage cleaned the MAFs and touch wood, all is ok. Hope this helps. Chris.

Shop, Chris

Thanks very much for your replies, it certainly gives me something to work with. I'll get some accurate readings off the MAFs and at least this will hopefully narrow down the problem.

If there was issues with hoses would this show when you check the MAF readings? (sorry all a bit new to this technical stuff..)

Yup, could be a vacuum leak somewhere else, too. Check all the little vacuum hoses running all over the inlet manifold. You'll have to remove the airbox to see them all.

This might be the source of your problems, actually.

Possible Causes

Mass Air Flow Sensor (G70) defective Intake System Leak(s)

Possible Solutions

Check Mass Air Flow Sensor (G70) Check Fuel Pressure Regulation Check Fuel Pump Check Injectors Check Intake System for Leaks Check Exhaust System for Leaks Check Secondary Air System for Leaks Check Vacuum Pipes for Leaks



Possible Causes

Fuel system Excessive fuel pressure Leaking or contaminated fuel injectors Leaking fuel pressure regulator Low fuel pressure or running out of fuel Vapor recovery system Air leaks after the MAF Vacuum leaks Improper seated engine oil dipstick Stuck EGR valve Oil overfill Cam timing Cylinder compression Exhaust leaks before or near HO2Ss.

Some more info on the trim and MAFs most likely.

http://www.ross-tech.com/vag-com/cars/fuel-trim.html

R

Just to close this particular post... It did appear to be down to the MAF sensors. Since these have been replaced the light has gone off and car has been running well (until recent fuel pump issue - but thats another post )

Thanks for all the help and suggestions.

Gary