Audi TT Forum banner
1 - 20 of 40 Posts

·
Registered
Joined
·
114 Posts
Discussion Starter · #1 ·
Please help, awesome is closed as its good friday.

My bat went flat over night as i left my lights on. tried to jump start it this morning but when i tried to start the TT it starts but stalls straight away. when i put the ignition on, non of the red dash computers light and my headlights dash light flickers really quickly!

IS MY ECU FRIED?

Any comments will be very appreciated.

Tim
 

·
Registered
Joined
·
367 Posts
Sounds like he tried to jump it, which really isn't good news, should unplug the ECU before doing it. You may have got off lucky but I don't know how you can find out. Good luck though!!!! hope it works out ok!
 

·
Administrator
2001 Amulet Red 225 coupe.Owned from new as well as a Nurburg VXR & an XR3, all from new.
Joined
·
97,178 Posts
Hi, May have damaged dash pod with voltage spikes..Make sure ign off & doors closed..Check your jump battery connections again on both batteries & try start again.
Hoggy. :D
 

·
Registered
Joined
·
7,425 Posts
:lol: Like that idea, doenst work use a bigger battery :roll: :lol:
 

·
Registered
Joined
·
114 Posts
Discussion Starter · #10 ·
Right guys ive tried all the above. same problem, No Pod Computers, No Gauge readings and car starts but then cuts out. ive noticed 1 other thing, my green headlight bulb flickers really quickly even when the ignition is off [smiley=bigcry.gif] [smiley=bigcry.gif] [smiley=bigcry.gif]
 

·
Administrator
Joined
·
33,050 Posts
Disconnect your battery for a couple of minutes in order to properly reset any processor based modules (including dashpod). Make sure your battery is properly charged before reconnecting and when you do don't bounce the connections making sparks etc. - that could cause processor lock up which is perhaps what's happened when you were jump starting. Make sure when you reconnect the battery you connect the second teminal firmly in one go withut bouncing the connection, tighten and try starting again.

If that doesn't work, disconnect the battery for much longer then try again. If it still stalls after a second after starting normally it would appear to be a dashpod failure as that handles the immobiliser security handshake with the ECU. The ECU will cut the engine after one second of running if it doesn't receive an authenticated message from the dashpod.
 

·
Registered
Joined
·
732 Posts
If jumping off..........have sidelights on when you jump off ( tip I was unaware of until recently ,it takes surge away from ecu)
If battery has discharged for some reason best option is to charge overnight or try new battery
 

·
Registered
Joined
·
4,917 Posts
As John-H said disconnect but be prepared to leave it half an hour or more. My car takes ages to completely discharge the ecu - well over an hour!!!

Good luck
 

·
Registered
Joined
·
367 Posts
I don't know if the TT starts with the ECU out or not, all I know is you never ever jump start an elise without disconnecting the ECU first as you will most likely fry it. So imagined it would be the same with the TT.
 

·
Administrator
Joined
·
33,050 Posts
maceonline said:
if it is my dashpod cutting the car out, whats my next step.....as when i connected the jump leads it did spark!!!
It's not a problem if the jump leads spark as that just indicates a current is flowing between batteries. The problem comes when the battery voltage drops too far then recovers - during cranking on a nearly flat battery, or when jump starting if the leads are not heavy duty enough, or when reconnecting a battery if the connections bounce.

What can happen is that when the voltage drops too far, the processor can corrupt data or crash and lock up. If at that moment the voltage recovers before the processor is properly reset, the processor can remain in a corrupted or locked up state and refuse to function properly. Normally there is a reset circuit that relies on the voltage coming up cleanly and remaining above a certain level before releasing the processor from reset - but it needs time to discharge proerly before power is reapplied. The dashpod processor runs continuously even with the ignition turned off for as long as battery voltage is present. If it is locked up you need to remove power to give it a chance to power up properly.

In your case if this happened when jumping the car your dashpod may not function and not talk to the ECU.

It's worth checking fuses too as the engine running symptoms would be the same as regards the immobiliser function if there's no power to the dashpod.

Couple of other points:

Without the ECU connected the car will not start.

When jump starting it's a good idea to keep the lights turned on on both cars during disconnection of the jump leads, as what can happen is that if an alternator was previously supplying a high current into the load and that load is suddenly disconnected a surge in voltage may occur, so keeping a load present damps down the overshoot in voltage before the alternator recovers its composure.
 

·
Registered
Joined
·
114 Posts
Discussion Starter · #19 ·
Right guys, fully charged battery now but all the same problems. Car strats for a seccond then cuts out, also dashpod not displaying the red computers. can anybody give me anything to try as i carnt get my car booked in anywhere till Tuesday [smiley=bigcry.gif]

Thanks
 

·
Administrator
Joined
·
33,050 Posts
1 - 20 of 40 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top