Hello,

Impossible to start my Octavia 4x4 combi TDi90 [2003, 150000kms]

- battery is verified and OK

- starting with another battery or cables is also impossible

Someone has suggest me to replace the Neiman contactor ; it has be done...for nothing.

Symptoms :

Interior lights set to ON

POSITION 1 (key inserted and turned) :

- all the correct warning lights light,

- the battery light warning is not very shiny

- the interior ligh is diming

- all the warning lights switch off exept :

- battery

- beaks

- ABS

- a "clac" sound of a relay

- interior light become more shiny

- so the battery warning light

- the ABS warning light switch on

POSITION 2 : start

- all the warning lights switch off

- the electrical doors locking system close some of doors

- a far away noise of a engine starting....very...very...slow and nothing

Is seems like a electrical short-circuit when starting.

Anyone has an idea

Sounds like a bad starter motor . The clac sound is the noise you get with a healthy starter solenoid.

What voltage do you see when trying to start? If you see a very low voltage then the starter motor may be partially siezed. The low voltage may cause the X contact relief relay to drop out as well as causing the central convenience unit to malfunction.

Ok,

I will make the voltage tests, but I should point out that, when using another battery (I first though it was a battery problem) with cables, the plastic protections were starting to smoke, and the cables were very hot.

I am French , and have not very well understood the suggested technical problem explanation, but have got an idea of what would be changed, in the worst case ?

Tank You

David.

The battery voltage is falling because of the large current being taken. This also explains your observations of warning lights etc.

Possible causes:

1) Starter motor is jammed. Take it out and check that it not being mechanically constrained by the flywheel or its engagement mechanism.

2) Starter motor has failed short circuit - possibly a winding shorting to the case.

In both cases, take out the starter motor to investigate further

Where is the starter motor ?

Is there any tough tasks and warning about its de-assembling ?

Thanks.

David.

If the jump cables are getting hot then more likely the short circuit.

Certainly seems like starter motor fault.

Starter motor is removed from below.

Disconnect cable and plug from the top and remove top fixing bolt

From below remove the underbody shield, various brackets, components and fixings that are in the way and then the lower starter fixing bolt. Gently lower from below.