2002 audi a4 1.8t quattro replaced fan relay car wont start


Asked by Jun 16, 2017 at 09:59 AM about the 2002 Audi A4 1.8T quattro Sedan AWD

Question type: Maintenance & Repair

2002 audi a4 1.8t quattro 5 speed, 1st the fan relay was staying on and draining my battery i replaced the relay and spray wire dry on the connection cause water was in where ecu is and now car wont start.

11 Answers


If water reached the ECU it is more than likely damaged it,


No it didnt as it was draining into car, car ran prior, just that fan relay would go on after i was parked and drain battery i replaced it and sprayed wire dry on the connection

1 people found this helpful.

After battery drain has it cranked since?


Low voltage will cause havoc on the ECM,cuaseing it to loose memory of your chip key,if this is your issue a dealer will have to reset the ecm and program the key back to it.


No battery issue car cranks, no issue with key also

1 people found this helpful.

If engine is turning,and doe,s not run,what i meant was the fan running battery down causing low voltage will cause ECM shortage,loosing memory to your key,this will not kill fire to the engine but will kill the fuel to it,to check what i said,check the fuel pressure,this will let you know.


Ah, ok how do i check fuel pressure.

1 people found this helpful.

You can rent a fuel pressure guage from most part,s store,s,hook it to the fuel rail cap at the fuel rail ,turn key and crank car over a few time,s,it will give you a pressure,if no pressure then the issue will be what i said.


Thank you.. but i didnt have a starting issue until i changed the relay and the fuel pump is new actually had that installed last week

1 people found this helpful.

Have you checked your main fuse,s?Main/ecm,etc


ah what fuse would be the main fuse please.

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