Audi a4 1.8T electric Problems

[Damian1902]

Hi Last week I bought an Audi a4 1.8T 54plate convertible.
On the dashbord it had a ABS and traction light was on.
Been told its a Sensor and not affecting drive.
Also central locking didnt work, also light inside and left number plate bulb wasnt working.
Next day I had problem with electric.
The windows and the roof stopped working and I cold feel the engine wasnt running sooth but with little shake.
I disconnect battery and connect it again.
After that The windows and the roof start working.
I also reprogramed the key and central locking works fine. Ive changed the Cabin fillter and spotteds the black Cable is unplugged.

Yesterday I took the car to car Wash.
After 10 mins driving I couldnt press the break and also the Rpm was dropping under 10000 and engine was shaking,
When I opened the bonnet see water around the battery so I went for coffee so it could dry.
After an hour I reconnect a battery but nothing has changed.
Also spotted when driving on lover gear and keep the Rpm above 20000 break was worrking fine.
Any ideas whats that could be?

 

[NHN]

Check for water build up under the battery due to blocked plug, when this blocks it can overflow into the cabin & floods the convenience module under passenger seat & thus creates numerous electrical issues.

 

[Damian1902]

There was the water under the battery definetly, also when we switch the heat on passanger seat my miss says its smells like warn clutch.

 

[NHN]

Sounds like water ingress, fixed these numerous times.

 

[pauldazzle]

As NHN has stated blocked drain plugs in the Plenum Chamber are the usual culprit. Water ingress rots out the bottom of the Brake Servo causing hard brake pedal, water ingress into the ECU box, & the relays underneath it can cause electrical chaos. Central Convenience Module is also at risk so check around the drivers footwell for damp carpet.