I have an 04 Polaris Sportsman 400 EFI that the battery had died and my son hooked the battery charger up to it... BACKWARDS!!...since then no power to anything. I put a brand new battery in it and still nothing. I am pretty sure it is the ECM but do not want to spend $400 on it to find it is something else. So I am wondering if anyone else has had this happen or has any ideas. I pulled the wire loom off from the starter solenoid to the ECM and found no fusible links or burned wires. I am at my wit's end, so any help would be greatly appreciated.

 

Your machine is listed under the recall , if you have the old ecm , you can get a new one at no charge

https://www.cpsc.gov/Recalls/2008/po...o-fire-hazard1

 

If you have to buy , ebay has a much better price -
https://www.ebay.com/itm/Polaris-Sportsman-Scrambler-400-500-Surepower-ECM-2004-2005-2006-2203348/184077368394?epid=1111855485&hash=item2adbddbc4a:g 4kAAOSwVTpd79Ic

 

I just called the dealer.the other day about getting an ecm replaced on a 05 trailboss, and I was told the recall has expired. Kind of shocked, as this is a safety issue.
I have bought one of those $150 ecms off Ebay for my sportsman 450 almost 3 years ago now, and have not had any issues yet.
Some of those ecms can also be opened up, to look at the board to see if you fried it. Pretty good chance it's toast.

 

I believe the dealer is mistaken , as you said it's a safety recall , they still have to fix them , I would call another dealer or Polaris directly .

 

They said that the ecm was tested back in 05, and tested ok. That's the only reason I can see them saying they won't honor the recall. I guess that's their way of saying it was done?
In my case, on that trailboss, it ended up being the keyed switch. Had one lying around, swapped it in and fired right up.

 

I ordered a new ECM..(the dealer informed me that it wasn't an included machine).... and unfortunately, it did not solve the issue. I have all the wire loose and sperated from the wire loom and even replaced the fusible link(I found by pulling on the wires individually) with an inline fuse setup and still no power to anything. It's not like It has been abused...it has been in storage for 16 years and was used very little before that. I am unable to think of what else it may be... Again any help would be greatly appreciated.

 

Unfamiliar with your machine but are all grounds good? Power into fuse/breaker box?. Power out of fuse/breaker box? Power from your battery to ignition switch? Power out of ignition switch with key on? Use a multimeter and find where the power stops. Its a process of elimination until you find the problem.