2018 Polaris Sportsman 570 EPS UTE - Shuts off

[Boozy]

I have a 2018 Polaris Sportsman 570 EPS UTE, that when idling for a few minutes after being warm will just shut off. When I am riding I have to sometimes give it more throttle just to keep it going. RPMs at idle are around 1250-1300 but if I rev it and let the RPMs drop back down it will either stop around 1250-1300 or it will just shut off. I have replaced the spark plug, fuel pump (28-32PSI was the reason), cleaned out the exhaust for carbon build up (which there was none), replaced the battery, etc. I ended up purchasing a Check Tech and connected it to the machine and looked up error codes from history. One of the error codes that showed up was 636 - CPS (Crankshaft Position Sensor) might be faulty. According to the manual it says that it should be about .46v +- .003 and mine is running at .38. For giggles I took it out and plugged it into another machine and read the voltage and it was showing .45v. Does anyone have any other ideas of what to look for? This issue is driving me crazy. ATV is under warranty so I can get the parts but dealer appointments are a month out.

Edited July 14, 2022 by Boozy

[Mech]

Something on the bike might be shorting the CPS signal. Could be the wiring, you could wriggle wires with it idling listening for a missfire,  and look for chafing, or it could be electronic. Or, use an ohm gauge where the CPS connects,  and check for shorts to earth, or low impedence going into the control unit.The manual will tell you what to check next.. before you buy parts...

That figure of 46v +- .003 though, sounds a bit strange.. 4 point six would be a common sort of voltage for something like that, ad then point 003 + or - might be correct, but point 003 on 46 volts is nothing and a lot of gauges wouldn't even show it(analogue gauges).

You should be careful though you don't void the warranty by working on it yourself..

[Boozy]

Hey Mech, thank you for your response. The voltage is .46v not 46v according to the service manual which is what my 2019 is showing on CheckTech. My 2018 is showing between .36 and .38. I am not sure if that would cause a full issue, however, in the error code history it showed 636 - CPS possible fault. I have found the complete wiring diagram for the 570s and will try to locate the CPS on the stator case, which I believe is located under the left side paneling.

- I did start it up and tried jiggling the wires as you suggested to see if anything changed but nothing happened.

- I also checked out the wires and did not see anything that came loose out of the plastic tubing or seem to be damaged.

- Next will be connectors and checking the CPS connections/continuity on those wires. I do think I tested the resistance which was 1106 ohms and the service manual says 1000 +/- 10% which would be roughly 900-1100.

If I took a screenshot of the CheckTech outputs, would that help?

[Boozy]

Correction, CPS is on the right side and I tried wiggling the connection for it without any issues. I also checked the wiring and it looks like they have it routed perfectly through another plastic wire conduit and nothing was worn on the exposed wires. I have seen others having issues with their machines shutting off once it has warmed up and when they wiggled the wires for the CPS caused the shut off. But I am going to get some sleep and look around again tomorrow.

[Mech]

Ha.. my bad eyes..

I'm not familiar with those bikes but it's common in lots of auto software that a trouble code will set for crank position sensor if the crank kicks backwards because of either a bad startup attempt or because the crank got rotated backwards via the driveline. The code is just an indicator of where to look. And gauges vary by some percentage right from new, even the best of them, then with age they can get out by even more, so the readings of the sensors needs to be taken as an indication too. If the readings are close to the manuals recommended, but steady, I generally figure they are ok.

Some software will decide there is a crank position(or cam position) problem, if either of the two readings get too far out of the expected positions.. as can be caused by worn cam chains or slippers.

[Boozy]

No problem Mech. Thank you for your help...I still have my dealer tech appointment scheduled for the 27th so I have another 12 days to look into the issue before having to take it in. The fuel pump that I replaced does seem to be working a lot better and keeping the idle RPMs at 1250-1300, just wish I knew what causes the machine to die once warmed up while riding. The other thing that gets me is that when it does happen to stutter and shut off no lights are triggered.

[Mech]

Ok.. Stuttering to a stop once hot, then restarting again a half hour later, is a fairly common symptom of a faulty crank or cam sensor in vehicles.. some makes/models it's a well known fault. Not saying it is your problem, but it would fit. That's the good thing about these forums generally, people have seen such things and we hear if they are common faults to the vehicle.

You said one of the trouble codes was crank, so what were the others ? It's a good idea to note the existing codes, clear the record and restart and run the bike, then see what new codes you get..

Blocked fuel tank breather.. dirty fuel filter.. vacuum hose loose or holed..   These could cause it..  It's good to consider the circumstances as well as the symptoms.. So, is it time perhaps rather than temperature that causes it ? Does it always happen after some particular operator input ? It's always a good idea to pinpoint exactly, what circumstance induces the problem every time, then you generally get led to the faulty component or adjustment, and, you can test your repair with some certainty/confidence...

 

[Boozy]

@Mech I got it working without issue today. Between the fuel pump and CPS it was causing issues with keeping the bike going. After I replaced the fuel pump the other day, the bike felt a lot "stronger" but still had a die out issue not stutter. Replacing the CPS kept it running...I checked the ohms on it yesterday before going and getting the part and it was reading 1326 which is way out of band. Also, when I start my bike up it starts on the 1st or 2nd crank not the 3rd or 4th

[Mech]

Good one. Glad to hear it. Long may it last.. haha.

[jussygm90]

Where can you download the service manual for this atv free

[Mech]

Top of this page in "more", then service manuals, and on the new page over on the right you choose your make.

[shevard]

There was a similar reason disappeared when I changed the sensor.