car won't start after replacing fried DME
 

Hi folks. I'm troubleshooting a no-start problem on my sister's 1996 318ti. At first we were confused as to why the battery was dead and the car wasn't starting after a jump. I found a post on this forum about a problem with water getting in behind the battery and destroying the DME (ECU) and indeed there had just been a big rain storm here. We opened it up and confirmed that the DME was full of water and the circuit board was badly fried. We removed the dead DME and dried everything.

I bought a replacement DME on eBay (same part numbers, stickers, etc, same year too) and we swapped it in. The car is still not starting and we see the "check engine" light come on in Position 2 and never turn off. The starter does kick over fine but I haven't checked if the fuel pump is energised yet, it seems like there is no fuel and/or spark.

Any ideas on what to try next? Before removing the dead DME we confirmed that the fuses are in good shape (we replaced the fuel pump, rear defroster, and cigarette lighter fuses) and all of the important relays are working (bench-tested), at least the ones we believe are for the pump and DME.

The replacement DME must be "aligned" with the EWS II module. Usually has to be done by a dealer.

Wow, thanks, that's good to know. I didn't know that such a module existed. So we have to tow it to the dealer for sure then?

Make sure you clean the drains or this new DME may also go for a swim.