I have a 98 Subaru legacy Outback. A few weeks ago my check engine light came on. I had the codes run, and it came back PO-483 cooling fan malfunction. I read that if you car runs hot for 2 cycles that it will through this code. I checked my cooling system... water full, thermostat good, fuses good, nothing blocking the radiator that would make it get hot, fans are working turning on and off, and I have never noticed my car temp gauge going above the half way point. I even replaced a wire on the fan that looked a little iffy unplugged the battery for 15 minutes, and still had the check engine light. Should I just assume the fan is going out soon and buy a new fan? Do I replace booth or just the one that cools the radiator? Anyone have any other suggestions or things to check before I buy a new fan? And yes, of course I was literaly on my way to get my tags when the check engine light came on. I only have a week to figure this out, and I am at a loss...

weird, i just had this code pop up as well and i didn't find much info about it a week or two ago. few posts/info and most people never posted back what they did.  i cleared it with the scanner and it hasn't come back yet, but i'm sure it probably will.

An odd one for sure.

I know the fans are two speed fans, its possible the low speed is working and the high speed is not, or vice versa.

 

Plug in the two green connectors under the dash and turn the key to On. This will cause the fans to cycle and all of the relays and solenoids under the hood to click in roughly 1/2 - 1 second intervals.

You should hear two distinct speeds of the fans, a low speed, then a click and the high speed should come on.

If you only hear the one speed then you'll have to look into why. You can unplug each fan one at a time to isolate which fan is not working as it should.

 

Ill check what the FSM has to say about this code when I get a chance.

Edited July 23, 201312 yr by Fairtax4me

Thanks, I'll give that a try... as soon as I can find the second green connector. I saw one right off the bat, but I am having trouble locating the second one.

FSM isn't very useful on this one.

I'm thinkin the ECU is expecting to see a certain amount of drop (over a certain time) in coolant temp when the fans turn on, and if it doesn't drop fast enough it sets this code.

 

I would definitely check to see that both fans are working properly. That both speeds engage if your car has the two speed fans. Two speed fans will have 3 wires in the connector, easy to check by sticking your head under the radiator and looking at the fan plugs on the bottom of the fans.

 

Also make sure the radiator and AC condenser are clear of debris, dead bugs, dust, leaves, etc.

 

Green connectors should be close-by each other. They are only one wire each and fairly long leads though so someone may have wrapped the other end over top of some other harness under the dash.

Thanks, that second green connector was shoved way under there... So both fans spin at 2 different speeds, but the one on the drivers side seems to have a bit of lag at the slower speed. There is nothing caught in the blades or anything slowing it down. So guess the motor is going on it?

I would kind of assume that the fan is OK if it works at all.

The ECU has no way to directly monitor fan operation. There is no sensor that tells the ECU the fan is spinning, nor an ammeter circuit to detect current draw to tell if the fan is spinning as it should.

 

So the ECU only has the ECT sensor to rely on to tell if the fans are actually cooling the system. As a result, other cooling system problems could cause this code to set. Low coolant level, a thermostat not opening all the way, a partially clogged radiator, poor coolant circulation due to a worn water pump impeller, all possible causes.

 

Intermittent fan operation could be a possibility. A bad relay might not engage the low or high speed setting when commanded.