Random starting problems

[stevenc]

Petrol 1.8tsi, DSG. 2011

When normally starting the car  - turn on ignition – various warning lights appear on dash – certain ones disappear after a short time as it checks its systems – turn key and engine starts.

Some of the time this is the behaviour of my car, but now and again I turn on the ignition and two of the warning light never appear, namely the ‘Control system for exhaust’ (an orange symbol of an engine) and the EPC (orange) light.  When this happens the car will not start.  The starter motor turns but the engine does not fire.

I discovered that turning the ignition completely off and then on again several times will eventually get the two warning lights back. The car will now start. Once started it runs and performs normally.

I have done a few thing to try and fix the problem.  New battery. Cleaned main earthing point to body. Checked fuses and relays. 

I have scanned ecu for errors with Carista, and there are some (U0100, P1624, P1850) but nothing jumps out as the actual cause of the problem.

There must be a bad connection somewhere in the wiring but where to start?

[EDS89]

hello.

 

If there is exhaust light. Might be the catalyc bad oxygen 02 sensor under the exhaust system under the car.

 

And check the spark plugs and coil as well. 

[Rudi]

On 25/04/2019 at 15:46, stevenc said:

Petrol 1.8tsi, DSG. 2011

When normally starting the car  - turn on ignition – various warning lights appear on dash – certain ones disappear after a short time as it checks its systems – turn key and engine starts.

Some of the time this is the behaviour of my car, but now and again I turn on the ignition and two of the warning light never appear, namely the ‘Control system for exhaust’ (an orange symbol of an engine) and the EPC (orange) light.  When this happens the car will not start.  The starter motor turns but the engine does not fire.

I discovered that turning the ignition completely off and then on again several times will eventually get the two warning lights back. The car will now start. Once started it runs and performs normally.

I have done a few thing to try and fix the problem.  New battery. Cleaned main earthing point to body. Checked fuses and relays. 

I have scanned ecu for errors with Carista, and there are some (U0100, P1624, P1850) but nothing jumps out as the actual cause of the problem.

There must be a bad connection somewhere in the wiring but where to start?

 

I have a similar issue with my Octavia Mk2 TSI: car runs perfectly well, but very occasionally (once or twice a week) randomly cuts out, and twice in the last month it has cut out and not restarted (until left for about an hour) exhibiting similar symptoms to stevenc's Octy above (starter motor turns but not even a hint of the engine firing up). Car was serviced and MOT'd last week - garage (non-Skoda) said they could not find any faults on scanning...

 

Thoughts?