The other day after a rain, I heard something running as I walked up the driveway. Looked around and my '02 A4 radiator fans were running full speed with the key in my pocket and doors locked.

Upon inspection I found water on the driver's side carpet. I couldn't start the car since the battery was too weak. Jumped the car and got it into the garage and took things apart to dry it out.

Investigated and saw that the crappy German plastic ECU cover had a crack in it. Allowing water to run off of the windshield and into the ECU box then into the interior.

After several days of drying all the carpet and such, hook up the charged battery and now the vacuum pump continues to run and the radiator fans go on and off in a pulsating rythum with the ignition off. And the car cranks no start.

Codes before dry out: 17887 (Vacuum pump), 18010 (low voltage), 17095 (trans temps sensor)

Codes after the dry out: 17939 (Cam sensor), 01826 (steering sensor)

Help! Now what?

 

Might have found the issue. Realized waer was below the ECU. This is not my picture but mine was just like this on Google.

Where do I find relays 219, 373 and 395 cheap?

Not sure this will fix but worth a try.