EPC and enginefault lamp - unbelievable...

Dear fellow members

our Octavia background. 130.000km, timing chain replaced at 100.000 Engine type CAXA ( miles devide by 1,6)

After having the EPC warning light coming on around 125.000km and then disappearing by itself Intermediately, one day also the

Engine fault light came on. Then one day with engine warm - but not hot - it wouldn start!

So, I drew the code with a reader and got p0343 which indicates that the signal

from the cam-position sensor is unexpectadly high or low or faulty.

NOTE :  at all times the engine runs perfectly, no stalling, no loss of power - just as it should.

I replaced the sensor. Erased the code. But - no fix - Instead I got engine fault light on and this time TWO codes were found:

the old one p0343 plus a new: p0341 which indicates faulty cranksensor.

I replaced the crank sensor. ( not in a favourable position on the back-underside of the engine,  I might ad)

No the interesting part starts:

After replacing the cranksensor, the engine is cold, naturally, I started the engine and both warning lights,

EPC and engine fault were gone, codes erased by themselves and engine started and ran perfectly. Heureka !

On that same day of happiness, having the engine about as warm as on the first "no-start" above I needed to go

shopping - but the engine did not start, and both lights were on !

In dispair I just, having to try something, I changed back to the old camposition sensor. The engine started!

Aha - it was the crank sensor all along, one might think. I let the old camsensor in.

The next morning going for work, engine cold, it wouldnt start again ! What ??

Again, had to be creative, I changed back the new camsensor - and - the engine starts normally !

So this is how things look today: 

If the engine is cold, start it with the new camsensor, it will start immediately, and run perfectly for as long as you want.

But EPC light (only) will come on after a few miles, just when you se the temp- gauge starts moving from

it's bottom position. Then, if you let the engine cool down completely it will start again with the new sensor in,

and no lights showing at start up. Should you try to start it after, let's say, an hour, with some temp left it won t start.

No it will get even more exciting: SHOULD you, however, install the old sensor at this point, "half-warm"

it starts immediately ! 

So - for cold-start: use the new camsensor. For warm-start; use the old one. Once started it will run perfectly regardless

of which camsensor is in place.

but EPC will come on as described above,

Unless any of you engineers out there have an idea, I suppose I now will have to take my story to a Skoda-specialist.

/Markku

Stockholm