So I was riding my 04' sportsman 500 ho the other day. I did take it through a mud hole or two and rode her pretty hard all day. Long story short the check engine light comes on now and reads hot even before I turn the key over. I've tried cleaning out the front and back of the radiator and in jamming the fan and it doesn't seem to help. Could it be a censory issue? Any help would be much appreciated. Another thought, if the fan had gotten jammed, which it was, and couldn't come on when it should have, could it have tripped out the censor so it just reads hot all the time now? Not sure what to do, if anyone can help me out it would be great. Thanks guys.

 

See if the wire is still connected to the temperature sensor on the head. Item#2.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse If the fan is ok(you can run 12 volts direct to it to check) and still kicks on and off,possible that the temp sensor may have just shorted out showing hot at all times.It completes the ground path for the hot light. You can test it with an ohm meter. Check resistance when engine is cold. Should show at least some resistance,then goes down as the engine warms up. If the sensor zeros out when grounded,just replace it. Plus not a bad idea to raise the front end,leave the radiator cap off and run the engine until the fan cycles on and off several times to purge any trapped air.If the fan doesn't kick on and off,majority of the time it's the radiator sensor. Item#21 .http://www.cyclepartswarehouse.com/f...2004&fveh=5632

 

Ok so I've done everything u mentioned above and at this point everything checks out. So unless I misread something you posted above, it leads me to conclude that the sensor chip has gone bad. Would that be a good assumption? If so, my only other question would be if you know the exact part I should order for my 04' sportsman 500? Thanks again for the help.

 

Also I believe it would be the ECM module 4010937 400/500 sscb. Just wondering if you can confirm that that is most likely the cause of the problem and possibly refer me to that exact part?

 

Yep! Keep forgetting about that the recall was expanded which included the 2004 models also a little later on as I did mostly all the 2005 models for the most part. One 2004 model had the regulator. If you have the ecm,you have the AQ model.Polaris Industries Expands Recall of ATVs Due to Fire Hazard | CPSC.gov Hard to test this module,but it controlled the fan operation,battery protection circuit,charging along with having other functions. IF the fan kicks on,it's charging at least 14 volts,but the hot light still stays on,still could just be the sensor on the head shorted as it completes the ground path for the hot light. Item #2 on the parts break down. Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse But the resistance test I mentioned can tell if it's faulty or not.If it tests out ok,then the crappy ecm has failed.This is what the ecm updates to.http://www.ebay.com/itm/2004-2006-Polaris-Sportsman-and-Scrambler-400-450-500-OEM-Surepower-ECM-2005-PDM-/171576768506?hash=item27f2c5b7fa&vxp=mtr "IF" you have the original BLACK Chinese module(some still floating around like this) the replacement is at no cost to you. Just call an area dealer with your vin# to schedule for it to be replaced as there is no time limit on a safety recall.