Yeah I got a problem with my friends car. We swapped out the tranny (for a third time), and this time we start up the car it runs fine, tranny is fine. Take it for a spin. After the car warms up fully, ecu tries to go in the closed loop and check engine light goes on (had this problem before heater wasn't wired up by previous owner). Well this time CEL goes on 2 seconds later car just dies out. So I check the ecu fuse and it's blown.

Replace the fuse drive again, car dies again the same freaken way. So I check the o2 plug and it was melted so I just cut the bitch off for time being and I wrapped in electrical tape (each wire seperatly). Run it again this time car dies again. So I check a4 plug (o2 sensor heater wire on the ECU) and it got power (car off). So I wasn't exactly sure but that wire isn't supposed to have power, right?

Cliff notes: A4 (heater wire) got power (12V) going thru it when the car is totaly off. This would cause the ecu fuse to blow everytime it would try to go into a closed loop, right???

SORRY ABOUT THE TITLE BUT I SCREWED UP

 

Anybody???

Is there supposed to be power in heaterwire (with ECU unplugged and car off).

 

the power should only be there when the car is in ign or on mode. when the car is off [key out] there shouldnt be any power. trace the wiring. could be a possible short.