cliffcoggin

I don't know the answer Dan, but I recall the question being asked a few times in the past. A look through the forum history may be helpful.

Whether it is a belt or a chain it needs to be looked at. If it fails it could wreck your engine.

I am not sure I fully understand the problem. Does the engine speed, as shown by the tachometer, truly go up and down, or is it just the indicator lights that are changing?

Glad to hear it. Confirmation of the solution would have been helpful to others in a similar situation.

None at all. I did not know of a primary air pump, let alone a secondary pump. Or have I misunderstood? The lack of punctuation makes it difficult sometimes.

Please confirm you are using an automatic gearbox.

Corrie. Did you find a solution, or did you concede defeat?

Craig. Did you find the leak? How did you rectify it?

Ben. Did Stevey's answer help? Have you resolved the problem?

Do you have a question?

Possibly the cam belt tensioner flopping around. How many miles since the cam belt was renewed? Or is it a chain drive?

How old is the battery Jim?

Thank you Roy. Evidently I am out of touch with modern developments, though modern may not be the best term to use considering the article was written ten years ago in USA, a country whose diesel development tended to be behind Europe. I have always avoided getting too involved in discussion of anything electronic because of my ignorance of the matter. I guess now it is time to realise my knowledge of modern engines is equally lacking.

Martin. So many correspondants here have reported glow plug faults from code readers that turned out to be entirely unrelated to glow plugs that I begin to wonder if "glow plug fault" is the default error mode for anything the readers do not understand. Even if there is a problem with the glow plugs you will not notice any difference in performance because the glow plugs do not operate when the engine is running. Their only role is to help start the engine in cold conditions by raising the temperature of the fuel/air mixture enough for auto ignition to occur.

Mmm. Cotes du Rhone I hope. Nothing but the best for an Audi.

If you bought the stereo from Halfords I suggest getting them to fit it, even if it costs a bit more. Let them have the problem of finding the right wires and connectors and fittings and screws and brackets.

An early Christmas present perhaps?

If you are prepared to open the fusebox cover at the end of the dashboard, you will be able to connect a wire to an ignition switched supply. It's what I did to power a satnav.

Surely the mechanic neighbour who found the leak can also advise on its repair?

My guess is that either a clip or a battery contact is damaged causing an open circuit. You might be able to bend the contacts for better connection, but I know of no way to repair a broken clip. As you have only the one defective key it is probably time to save some cash for a new one.

Craig. Are you sure it is coolant, not screen wash fluid or brake fluid? Coolant leaks are normally worse when hot because the pressure increases. How much is the level dropping in the coolant header tank over a week?

Sorry Lamar. I don't download anything from strangers. If you put the video on a public platform I'd be happy to watch it there.

Callum. How do you know it has lost its gas? There may be another fault such as compressor drive failure, which I assume is a belt. Whether the AC should have developed any sort of fault in two years is debatable. The fact remains that it has and if the guarantee does not cover its repair you will have to foot the bill yourself.

I had those symptoms a few years ago on mine, together with loss of cruise control and loss of air conditioning. Turning off the engine for half an hour restored normal operation. The problem was caused by a defective battery, so fitting a new battery solved all the problems entirely. I am not saying that is definitely what is wrong with yours, but it has become apparent to me since then that defective batteries can cause all sorts of strange electronic faults that do not show up on code readers, a fact confirmed by the mechanic who rectified mine. What makes it harder to diagnose is that a simple voltage test of the battery will not show anything untoward; it needs a deep discharge test, which most owners do not have the equipment for, to reveal the fault. If you can not find any other fault and if your battery is more than four years old I suggest you get a new one, not a secondhand one. It will have to be coded to the car by the installer.

I recall a similar topic here within the last couple of years if you care to look through forum history. I have a feeling it was related to a faulty instrument cluster but have no certainty of that. Other than that, get the car scanned with a decent professional grade reader.