salamalas Posted October 19, 2010 Share Posted October 19, 2010 So here's what I know, I did a coolant drain and refill, radiator only, not the block and noticed my fans weren't on when the car was idling fully warmed up, a buddy of mine suggested jumping the relay to the fans to test if it was the relay, i tried with a paper clip, nothing happened, shut the car off, put the relay back in, started the car and now I have a P0480 code. I have cleared the code but it comes back, I have swapped out the relay, still have the code, I drained the coolant and replaced the ECT, but I still get the code. The Main fan runs non-stop as long as the key is in the on Position or the car is running. Both fans run when the a/c is on. I have no idea what else to check, any and all advice is greatly appreciated. thanks 2001 outback wagon limited Manual, 2.5 liter, a/c ABS Link to comment Share on other sites More sharing options...
hankosolder2 Posted October 19, 2010 Share Posted October 19, 2010 I wonder if when you were jumping the cooling fan relay, you accidentally connected to one of the "coil" terminals of the relay socket rather than the "contact" terminals of the relay socket. If so, you may have fried the cooling fan relay driver circuit inside the main ECM. I'd also check all the fan fuses... I don't know about your particular car, but the earlier ones had at least two cooling fan fuses- one under the hood and one in the under dash fusebox. Nathan Link to comment Share on other sites More sharing options...
nipper Posted October 19, 2010 Share Posted October 19, 2010 I think you fried the ECM. Always on is the default safe mode when the circuit gets fried. On OBDII cars, never assume any circuit can handle 12v or full current of being jumped. If the wires are thin, then they most likely can not take a direct jump. Also circuits do not run the way people think. Ciruits tend to go to ground through the ECU, so jumping the worng side can cause the magical smoke to escape and throw a CEL. Link to comment Share on other sites More sharing options...
johnceggleston Posted October 19, 2010 Share Posted October 19, 2010 fan always on is also a sign of green diagnostic connectors connected, but you should also have lots of codes. Link to comment Share on other sites More sharing options...
salamalas Posted October 19, 2010 Author Share Posted October 19, 2010 So how to I check if it's th ECM, and do I have to replace the entire ECM or can I just replace the fan circuit? Link to comment Share on other sites More sharing options...
nipper Posted October 19, 2010 Share Posted October 19, 2010 Entire ECU (not ECM). i doubt you have lots of codes, but you blew the circuit. It is not a complicated circuit to diagnose. Link to comment Share on other sites More sharing options...
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