how to tell if your ecm is bad on a polaris

billnate · #1 (**permalink**) 01-12-2010, 03:37 PM

help, my 500 atp ,when i turn unit on and startit, it runs fine untill i turn on the headlamps,them it shuts down, i have replaced the ecm but it was no help.

**Bruce!** · #2 (**permalink**) 01-12-2010, 03:49 PM

First off, welcome to the board!

**blueline15** · #3 (**permalink**) 01-12-2010, 05:27 PM

makes me wonder if your stator is going bad. im thinking that once you turn on the headlights and require the extra voltage, the stator is not able to continue to put out enough volts to run all the electrical, so you loose the required volts to run componets like the ECU, thus shutting down the machine. thats just a first impression guess

donwest · #4 (**permalink**) 01-13-2010, 01:56 PM

My 2005 Sportsman 500HO was doing the exact same thing. Had the ECM replaced under recall for free and issue was solved. How long ago was the ECM replaced and was the replacement ECM new or used? URL="http://www.cpsc.gov/cpscpub/prerel/prhtml08/08193.html"]http://www.cpsc.gov/cpscpub/prerel/prhtml08/08193.html[/URL]

**blueline15** · #5 (**permalink**) 01-13-2010, 02:02 PM

donwest, you bring up a good point.

billnate, if you PM your vin# i can run it on the dealer site and check to see if you have a pending ECM recall or not. only takes a few minutes to do. various 04-06 models fell under the recall

donwest · #6 (**permalink**) 01-14-2010, 01:33 PM

Additionally, mine would start and run with the headlights already on. That is, flip the lights on before starting.

billnate · #7 (**permalink**) 01-15-2010, 07:33 AM

ok,here you are. i have replaced ecm with new and lt handlebar switch this week. i still have the problem,with key in on poss. i have taillamps.with lt handlebar brake lever locked on and i turn key on,i have no power,the red/wht stripe wire is going to grd. with all hdlps disc and brake lever not locked i have power and unit runs fine,ive checked stator,yellow wires do not go to grd and have continuity between them. with engine running i have 14.5 vlts @batt. with key on and engine not running i have 12.4vlts on batt.

donwest · #8 (**permalink**) 01-15-2010, 01:26 PM

Don't have access to a wiring diagram at work and can't download one. Sounds like a short in the light/brake circuit causing ecm to fail. Everything is tied together..if I remember, the cooling fan was even tied into the wiring to the light switch. What year is your 500? I'll try to find a diagram for it to offer suggestions on where to look.

billnate · #9 (**permalink**) 01-16-2010, 04:03 AM

thank you for responding to my problem. the atp500 is a 2005

donwest · #10 (**permalink**) 01-21-2010, 11:36 AM

With your key in on position, your tail lights should be on. My 2002, 2003 and 2005 Sportsman machines all operate as you describe. I still haven't found a diagram but can't access http://pdfdatabase.com/wiring-diagra...tsman-500.html from this PC. It still sounds to me like a short in your brake light/tail light circuit or a bad ECM. I know you replaced the ECM but it's possible to have received a bad one with as many that were recalled. If you haven't had your machine in for the recall, it's free and may eliminate your headache....maybe.