Car Won't Start, No Dash Lights, Have To Reconnect Battery

[CraigClark]

I've got a 2005 Plate Audi A3 Sport, which I've had for roughly 3 weeks.

On a few occasions since I've had the Car, I've come out of the house to find that the Car won't start.

It unlocks fine, Stereo will work fine, along with the Lights, Heating, etc, & you can hear the Car trying to turn over, however it just won't start.

When this happens, there are no lights or Symbols displayed on the Dash at first, not even the Mileage or the Time & Date, etc.
If I turn the ignition off & try to start the Car again, all of the Symbols on the right hand side will appear for a few seconds & will then disappear, the Computer will come on where it displays the amount of fuel left in the tank, etc, but nothing else.

If I disconnect the Battery & then re-connect it a few seconds later, the Car then starts fine & everything appears on the Dash as it should.

Any ideas because I'm completely baffled by this.

[alankru]

I don't know if this is any help to you:

http://www.vwaudiforum.co.uk/forum/showthread.php?123699-Immobiliser-Problem

[JayA3sline]

Sounds like I an issue I had, all of the above that you stated I had too except when I turned the key in the ignition to start my car this awful noise occurrd, which was the solenoid opening an closing. Think you may need a new battery, go into a local garage/dealer to test it. Or put your meter across to test the voltage/amps on your current battery.

[Mike Foster]

First thing to do is have your battery checked for performance under load. Any reputable garage will have the appropriate piece of kit which is NOT a voltmeter. It needs to check the voltage drop when subjecting the battery to the type of surge current it experiences when starting the car.

If that checks out ok then remove the terminals and clean thoroughly with sandpaper before replacing. Also check the earth connection from battery to chassis and engine.

If everything checks ok and the problem still occurs then I'm afraid it's back to Audi !

[JayA3sline]

... When I was referring to testing the battery I was on about after the battery had been disconnected, in which case a meter can be used. Obviously under load is a different story.

[Mike Foster]

... When I was referring to testing the battery I was on about after the battery had been disconnected, in which case a meter can be used. Obviously under load is a different story.

Yes Jay I appreciate that is possible but, as has just happened to me, that method of testing does not give a true reflection of the state of the battery. My battery showed 12.2 volts when 'at rest' in the car. When tested off the car and under load it dropped to 9.8 volts indicating that at least one, if not two cells were duff !

Needless to say I had to get a replacement !

To be honest, I think in Craigs' situation it is probably more like a bad connection problem bearing in mind the fact that it starts ok after disconnecting and then reconnecting.

Craig, have you had the car scanned for faults ? I see you are in Leeds and I am between Leeds and Wakefield and would be happy to scan it for you if you wish. Can't guarantee a fix but at least you would have the diagnostics to take somewhere ( I can recommend the place I use in Leeds ). PM me if interested.

[CraigClark]

Okay so 6 Months on & still having problems.

I had the Battery changed for a brand new one, however this only made slight improvement.

The problem still occurs, only not as often, maybe once a week.

I've also noticed that when it happens, the Radio flashes up 'SAFE' for a second while the lights on the dash come on & then goes off again. Its at this point that I have to disconnect & re-connect the Battery Cables.

I had the Car scanned with a diagnostics machine, however this didn't pull back any errors..odd.

[CraigClark]

I managed to take the below picture last time it happened, this is all I get until I remove the negative lead from the battery, leave it disconnected for a minute or so & then re-connect it. Everything then comes back to life & I am able to start the car.
18427

[CraigClark]

In the end I pulled the clocks (instrument cluster) out, checked the part number on the top of them, purchased a set of clocks from Ebay with the exact same part number & then took the car & the new set of clocks to Mark at MT Motors in Gildersome (Leeds) to code the new clocks in for me. Mark did an excellent job & the car started to run perfectly after this.