I haven't look at the diagrams, but obviously our 4x4 is engaged by a switch, which means voltage going someplace. I'd checked the related fuses, check the switch functions..does power make it to the switch, does it make it out when you throw the switch to 4x4?
Then follow the power, assuming it goes into the differential, is the harness sending the voltage to the diff when you throw the switch?
Could be something as simple as a fuse or a switch failing, or a wire chafed...usually is something simple...eliminate those options before taking it in.

 

Thanks for the thoughts. Low power to diff is something that I need to measure. Fuses are good and power is getting there still as the front diff engages sometimes. It’s like it depends what mood the diff is in :grin. Looked at wires/ connections coming in and all looks good on the surface.

Also, this unit has not been wrecked, rolled over, or has sustained any kind of damage in very fun use. I love this thing.

 

Check the grounding path. Grounds have caused more misery in the 12v world ...

 

Are you sure that your getting down below the maximum engagement RPM after you flip the switch and before you start up the hill? You will be almost stopped. About 3200 rpm. The 4x4 symbol will them light in the dash.

 

Any pops, clunks, etc? Does it randomly engage in 2wd at all?

Check voltage at the plug for sure, 12v (gray wire) will be constant with the key, the brown/white is ground and should go on/off with the AWD switch.

Test resistance at the plug on the diff side ( unplugged ), should be 21-27 ohms.

That means the electrical system as a whole is functioning as it should, now, that doesn’t rule out a loose or corroded ground, and it’s worth checking the wires where they go into the diff for loose or worn connections.

My somewhat informed opinion is that if it’s not randomly engaging in 2wd, and not making any pops or clunks, and the electrical checks out, then you have a loose or failing connection in the system... and those are always fun to chase


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Thanks for the responses guys.

FTB, thanks. I will check out grounding and yes shilo, the AWD was engaged. I never switch on or off unless I’m at a full stop. Just habit.

RWB, no noises vibration or anything coming out of the front end with or without the AWD engaged while driving. No random engagement in 2WD either. No leaks or loose stuff as well. I will go down the electrical route and see what I can find. Thanks for the all the options. I will update if I find something.

 

Are you sure you understand how the AWD operates in a Polaris?

When I first got mine, my buddy said as soon as you flip the switch, its in AWD. No, its not. Especially when half way up a hill, rear tires are spinning and you flip the switch.

Great description from RZRJoe in the TRE forum.

Quote-

"Sorry but this is not how the Polaris AWD system works. All models of Polaris AWD system work the EXACT same way. The design is based on the Hilliard differential. The front driveshaft, ring gear, and pinion gear spin 100% of the time whether in AWD or not. The AWD switch is wired to the ECU. When the ECU sees a contact closure from the switch and the rpms are below 3200 it sends a ground signal to the differential, the 12v+ is always hot at the differential. When the AWD is engaged an electromagnet pulls the armature plate away from the plate retainer. This allows rollers in the sprague to engage. The spragaue and rollers are sandwiched in between the ring gear and the output hubs. When the ring gear spins faster the sprague / hub assembly the rollers lock into slots into the ring gear creating the front drive.

The two hubs inside the Sprague control differential lock. Each hub has a set of rollers that controls lockup. However, they lockup at the same time creating a true "locked" differential, meaning both front pull 100% of the time. However, upon hard tire impact on one side, that hub will "ratchet" and momentarily unlock. This creates a loud "pop" from the differential and it's designed to save the differential. All be it sometimes it can break the sprague.

So just because you flip the AWD switch "on" does not mean it's in AWD mode. It's not in AWD mode until the ring gear speed exceeds the hub speed. It works the same way for forward or reverse."

-Close quote

LINKY

 

Thanks Rocky, I had actually read that already. And yes, I do understand these things very well and how the AWD works. This is my 3rd machine and have many 1000’s of miles behind the wheel. Outside of self inflicted damage I’ve caused to my RZR’s over the years, this is the first time I have a AWD issue.

 

UPDATE:

Well, checked all of the electrical and everything checked out. The only things I couldn’t properly check is the resistance. I have Fluke tester, but doesn’t do resistance. I ordered a Klein tester to do it. In any case, I started thinking back to when it may have started and what was new. In the last couple months, Ive installed lights, speakers/ amps, and a Dynojet tuner with some performance parts.

Went back to a stock tune and pulled power from the radio. Same thing. AWD worked sporadically. Went back and put the stage 2 tune back on. No difference. Then as a long shot, disconnected the Dynojet (leaving the stage 2 tune on the ecu) and BOOM, AWD is working normally! Seems the RZR’s AWD did not like the connected tuner.

I need to do more thorough testing tomorrow, but on the surface, this looks to be my problem.

Thanks all again for chiming in.

 

UPDATE:



Went back to a stock tune and pulled power from the radio. Same thing. AWD worked sporadically. Went back and put the stage 2 tune back on. No difference. Then as a long shot, disconnected the Dynojet (leaving the stage 2 tune on the ecu) and BOOM, AWD is working normally! Seems the RZR’s AWD did not like the connected tuner.

I need to do more thorough testing tomorrow, but on the surface, this looks to be my problem.

Thanks all again for chiming in.

What tune, electrical devices connected, or Dyojet connected should make no difference in the AWD working or not working. The Dynojet tuner uses the CAN bus to talk to the ECU and should not interfere with the diff working. The Dynojet is simply reading the OBD codes sent out by the ECU and acts a display.

The diff design is actually very simple. When the key is on the diff is supplied +12v directly from the fuse block. The AWD switch is wired to the ECU. When a contact closure is made at the ECU & the engine is below 3.2k rpms the ECU grounds the diff allowing AWD engagement. From there is 100% mechanical.

 

I think you have a loose connection at the diff plug, or somewhere under the hood that you may have bumped just right when you were unplugging the PVCX. There's no way having that plugged in would effect the operation of the front diff.

 

I agree and that's why I need to do more checking. Doesn't make sense to me either. I did test after unplugging and re-plugging the connector and the AWD still wasn't working correctly. It wasn't until I unplugged the tuner that it started working correctly/ better. I can't say I'm 100% convinced, but hope to do some more looking this weekend. I will post what I find.

 

22 ohms at the diff. Gonna plug the tuner back in and see what happens. Also going to look closer at everything under the hood. I have a lot going on there with all the aftermarket stuff. :surprise

 

Amature plate is bad. Common problem. Is it under warranty still?

 

It could be many things, not just the armature plate.