A4 coil packs

PauloMN

My A4 has become hesitant when accelerating over the past couple of days - the check engine light flashed this morning also - so I hooked up my laptop with Vag-com and got the following fault:

16684 random multiple cylinder misfire detected

I only have the shareware version so don't know which cylinder(s) is/are affected, but from what I read, chances are it's one/some of the coil packs. I have the car three years, was four years old when I got it and I assume the coils have never been replaced (nothing in the service history to indicate such anyway).

I've a few questions on this which I'd appreciate any feedback on:

1) Is it possible to test a coil pack using a multimeter (resistance values maybe) - would a duff one show up a different value to a good one?
2) I assume one coil can be replaced on its own, they don't all need to be replace together or anything?
3) Before I spend any cash, I was goin to remove the coils and spray switch cleaner into the contacts on them - would this be wise? Seems a coincidence this happened with the bad weather - I'm wondering if I just have a bad contact on one of them.
4) I suppose checking the plug condition would be good to do seeing as I'll have the coils off - I replaced the plugs around 20k miles ago so I guess there should be life left in them yet.

Thanks for any help.

beachlife

Probably not a coil!! If it was a coil it would usually say misfire on cylinder(1,2,3,4,etc.) if it sats RANDOM multiple misfire I.,d be looking at live data to see what my injection time is and checking lambda against maf.

PauloMN

It doesn't specify the cylinder because I have the shareware version. I've Googled the error and when reported with the full ver of the software, it also specifies the actual cylinder number.

The O2 sensors throw a specific error I think, not sure about the MAF.

beachlife

PauloMN wrote: »

It doesn't specify the cylinder because I have the shareware version. I've Googled the error and when reported with the full ver of the software, it also specifies the actual cylinder number.

The O2 sensors throw a specific error I think, not sure about the MAF.

I think it doesn't specify a cylinder because it's missing on more than one..
When I said check maf against lambda what I meant was check the relationship between the two to see if there were any fueling problems,I am guessing you are not a tech,so that one was my fault!!!
The fact you have a share ware version won't affect the code definition.

Here it is from the horses mouth...

16684/P0300/000768 - Random/Multiple Cylinder Misfire Detected

Possible Causes
Air Intake System leaking
Fuel Supply faulty
Injector(s) faulty
Ignition Cable(s) and/or Spark Plug(s) faulty
Ignition Coil(s) faulty
Exhaust Gas Recirculation (EGR) Valve (N18) stuck/open
Camshaft Position Sensor (G40) faulty


Possible Solutions
Check Misfire Recognition
Check Air Intake System
Check Fuel Supply
Check Injector(s) and Injector Sealing
Check Ignition Cable(s) and Spark Plug(s)
Check Ignition Coil(s)
Check Exhaust Gas Recirculation (EGR) Valve (N18)
Check Camshaft Position Sensor (G40)

Special Notes
This DTC indicates that one or multiple cylinders are misfiring, but the ECU fails to identify the cylinder.

1948Wolseley

Have you looked at your plugs? It sounds more like a plug problem than a coil problem to me (unless the problem is on the fuel side...).