Hi.

My 1.8t 4X4 Octavia has a strange problem. Occasionally (1 in 25) it doesn't start first go from hot.

I've only experienced this once, it turned over, started for a brief sec and cut out straight away. It seems to run for a brief second then stops. I'm thinking some sort of electrical/sensor problem? Started normally second attempt. My dad's had this a couple times as well, seems to do it when the engine is still warm. Never a problem from cold.

Wasn't worried about it too much but it happened to my mum the other day, took about 7 attempts to get it started!

Any ideas?

I have a VAG-COM cable and either I'm not using it properly (it's the USB version that uses the shareware version of VAGCOM) or the car has NO faults at all. I think it's more likely I'm not using the cable/software properly as I know of at least one electrical fault (electronic rear child locks don't work).

Any ideas?

Does the immobiliser warning light go out?, the amber one with the picture of the key. If it doesn't you have an immobiliser fault.

It could be the engine coolant temperature sensor giving an incorrect reading, if the readings are in parameters then it will not show a fault, the trouble is the ECU lacks a little common sense. If the engine is hot and you restart it in a few minutes time it is possible that the sensor is telling the ECU that the engine is cold, hence the mixture will be incorrect. Get into a measuring block where the temperature is displayed and see what it is saying, if it is 20 degrees and the engine is obviously hotter that will be the problem.

as far as I know the child locks are manual, the slot is designed to be operated by the end of the key.

Does the immobiliser warning light go out?, the amber one with the picture of the key. If it doesn't you have an immobiliser fault.

It could be the engine coolant temperature sensor giving an incorrect reading, if the readings are in parameters then it will not show a fault, the trouble is the ECU lacks a little common sense. If the engine is hot and you restart it in a few minutes time it is possible that the sensor is telling the ECU that the engine is cold, hence the mixture will be incorrect. Get into a measuring block where the temperature is displayed and see what it is saying, if it is 20 degrees and the engine is obviously hotter that will be the problem.

as far as I know the child locks are manual, the slot is designed to be operated by the end of the key.

Cheers. I was out in it today and did about five hot starts. No problem at all. My parents must be doing something wrong!!

RE the child locks, mine is an Elegnace model, the child locks are operated by a button on the drivers' door- it no longer works! Not a problem as I've usually got a bunch of mountain bikers in the back rather than kids (not much difference though!)