ECU in 97 VW Polo 1.9 SDi

pamweld

Hi we have a 97 VW Polo saloon 1.9SDi and my partner was using his battery from car to start a tractor, he then returned battery to car and connected it again forgetting car was still running(noise of tractor drowned it out). Once he made the connection the engine died and won't start anymore, it has been connected to diagnostic computer and relay and fuses are working perfect, the garage has come to the conclusion that he has blown the ECU.
Can you just buy a second hand ECU and slot it in or is it a bit more technical than that? Does it have to be programmed to a specific car? He was told its not worth his while buying a new one as car is worth very little but has been 100% reliable to this point so hoping it may be revived without spending a fortune on it!

Any help would be appreciated thanks!

paultronix

can the garage get any communication with the ecu,if so do you have details of any fault codes?
if you do decide to replace the ecu then yes you can use a 2nd hand one but it will need to be programmed to the car so probably best to be 100% sure that this is the problem first.

Ronnie Beck

Your garage's diagnostics equipment mightn't be good enough. Take it to a VW specialist. As above you would want to be sure it's gone. Does your glow plug light come on?

dieselbug

If you're sourcing a replacement make sure the Bosch part no's match. You can have the immobiliser removed and it will be plug and play but no immobiliser function.

Or if you fit the ecu, instrument cluster and ignition from the donor car, work's iirc.

pamweld

Thanks for all your input! ECU is definitely the casualty, he took it out last night and it had that blown electronic smell, opened it up and it has a hole burned through it so power surge from battery went straight to ECU! Glow plug light wasn't coming on and he tried wiring it straight to diesel pump, it would start but only for second, engine is perfect, its a really good car so be sorry to see it go but as I said if it costs too much it would prob not be worth doing as he only paid €250 for it 2 years ago but flew through NCT each time(including last month :-( )

dieselbug wrote: »

If you're sourcing a replacement make sure the Bosch part no's match. You can have the immobiliser removed and it will be plug and play but no immobiliser function.

Or if you fit the ecu, instrument cluster and ignition from the donor car, work's iirc.

Dieselbug does this mean that once he finds once second hand with same part number he only needs to remove immobiliser and no further programming needed?

Thanks again for all the replies! Much appreciated!

dieselbug

You will have to bring it to an ecu repair centre (I dont know any in your area) They should be able to make the ecu free running (no immobiliser)

Between the replacement and repair centre it's going to cost a couple of hundred at least.

dharn

As a matter of interest, how did he manage to remove the battery with the car running, or why

pamweld

TBH I'm not 100% sure how he did it! It was running when he disconnected it and stayed running without the battery, I always assumed battery is mainly for starting and after that only electrics like lights etc drain it so if all electrics off it should run ok, (stand to be corrected) he wanted to start a tractor so removed battery and put into tractor, got tractor running so took it back out, with tractor still running he couldn't hear the car engine and forgot it was still running and hooked it back up! once lead hit the pole it killed the car unfortunately. Very silly mistake but don't think he could have killed it any other way the engine was that good