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Audi A4 2006 - Check Engine Light on, carbon build up? Coolant Fans?


I have an Audi A4 2006 (130,000 miles): My check engine light came on when starting the car the first time in about a week. Previously, I had noticed it was starting up a little rougher than normal but it seemed to drive just fine.

The dealership said they did the diagnostics and found that all four cylinders misfired at some point during the evaluation. They honed in on cylinder 2 thinking it was a bad coil, they moved the coil to cylinder 4 and found it also misfired right away. However, they continued to explain that even though that may help, that would not be the reason all 4 cylinders were misfiring. They believe it could be caused from carbon collecting in the engine and similar to Pitt, it would be roughly $700 because it takes 5 hours and is very labor intensive. - - I did not get the codes from them, I’m going to call tomorrow and ask.

Has anyone heard of this? Are they trying to pull one over on me or do you believe it could actually cause misfires in all of my cylinders?

On a slightly different note, they said during the diagnostics they found that the coolant fan module was misfiring or not acting properly. Therefore, my 2nd fan was not working and the 1st fan was having to work harder. They said with this issue, to replace the fan and the module would be $1150.

This all seems steep for a check engine light to be on, but not blinking. Any advice/knowledge around this would be appreciated!

It’s deja vu all over again!:imp:

Find an independent shop that specializes on European cars. No need for the extra cost of dealership service.

Replacement OE fans cans be obscenely expensive. A generic replacement is under $100, although it won’t be an exact match, and some wiring work will be involved.

Unless you are in California you can get the codes read for free at many auto parts stores, along with a printout of possible causes. Report back with the code(s). You may already have them on your invoice from the dealer.

Is this a 2006 A4 or a 2007 A3???

What they’re telling you about the carbon is possible, but there are other things that can cause multiple misfires on multiple cylinders. Without the codes it’s tough to guess. Post them here when you get them and we’ll start there. NOTE: they should be listed on your copy of the shop order. You should always keep those. I don’t believe they’re trying to pull one over on you, but how well they did the diagnostics can only be guessed at without the codes.

As regards the cost… that’s the problem with owning an aging Audi. They’re great cars (my son has one, his second actually) but the cost of repairs is much higher than Toyotas or Hondas… or even VWs, with which they share some parts. VW owns Audi

I believe Carolyn has started a new thread for the 2006 A4 guy

The 2007 A3 discussion is toast, AFAIK

Sorry for the confusion from the other thread, I have an Audi A4 2006.

The codes were:
P0300 - They said this was due to random misfires of all my cylinders, they think this might be because of the carbon build up.
P0302 - Random Faults which they think is from coil 2, so they recommend replacing it.

I would change all the coils and hope for the best. If one is really failing the others aren’t far behind.
Especially in a 10+ y.o. Audi.

Carbon buildup is common. You might try an “Italian tuneup”: run at 4500 rpm on the expressway (65-70 mph) for 20 minutes.