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Discussion Starter #1
Hi All,
I had my bike parked for a while during the winter, never used it much. I took it out of the non-heated garage today and discovered the AWD not working. The indicator on the dash comes on, but I cannot get the AWD to engage. If I reverse with the override pressed, it will spin the fronts, but if I go in forward it will not spin the fronts. I never tried taking out of AWD and trying reverse. The bike only has about 350Km on it.

the wire connector going to the dif has four wires (red, red/white stripe, the other two I can't remember). what readings should I be getting, and across which pins do I test? Also the same with the wires to the dif at the connector, which do I measure for resistance and what is the expected value?

I\m thinking electrical, but maybe I'm heading down the wrong path? Any help would greatly be appreciated!!

Cheers,

Trevor
 

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What are you doing to try to spin the front wheels? The front wheels won't drive until the rear wheels slip. Did you jack up the rear end and try to drive forward while the rear wheels were spinning?

I suggest before assuming it's an electrical problem you change the front drive fluid that may be contaminated with water from condensation.
 

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Discussion Starter #3
Hi Latebird,
I was driving on snow/ice to get the back wheels to spin and the fronts did not engage while doing this. I also tried on a hill in my driveway on loose gravel, and still nothing.

I'll change out the dif fluid and see what that does for me. Not sure if my local polaris dealer is open these days, but I'll try it.
 

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If you can't get the Polaris brand oil, use ATF type F or Dexron at least in the interim period if the dealer is not open.
 

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Discussion Starter #5
Hey Latebird and anyone else that may have any ideas. I tried changing the dif fluid, I used ATF type F and no luck. So I tried changing it again, just to make sure nice clean fluid in the case, and still nothing. As mentioned previously, it does engage in reverse, but not if it always does that, or specific to my problem. Does anyone know the test parameters for testing the wires at the connector, what voltage across which pins and what resistance across which pins from the case side connector? At 342 miles, I would not have thought a lot of ware on these parts, but maybe so. Anyway I'd like to get the electrical sorted and eliminate that before removing the dif a tearing that down. cheers
 

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There were two different gear cases depending on the model number of your quad - I need to know if it is an:
A18SXA85B1, A18SXA85B7 or A18SXE85BM, A18SXE85BA, A18SXE85B9 MODEL
 

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OK - uses the same parts as the following models - I posted the info for the 2015-17 850
 

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Discussion Starter #10
So I just tested and a little strange. for voltage I got 12.27v between A and C and the same between B and C, but between A and D and B and D, I get 8.97v. (depending on which way you look at the connectors, but for argument sake lets say A and B are the two reds) I seen the correct lettering after I was all done, If you need to be more clear on that I can retest.

For resistance I'm getting 20.8 between A/D and 12.2 between B/C,

I do not make myself as a small engine mechanic, but I would think that these numbers should all be close to each other. is it possible that the voltage on drop associated on "D", is a bad ground? but not sure of the difference in ohms between the two measurements.

I have a pretty decent multi-meter (Greenlee) so I trust my numbers.....

Latebird, would you happen to have the specs for the 2018 850 SP?
 

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Well, that doesn't help me because I'm not sure of how you tested.

The ohms are close enough, but the voltage may or may not be right depending on how you connected the meter leads. I presume you had one lead on a ground (engine, frame or battery neg terminal) and with the gearcase lead plugged into the wiring harness you got 12v on the gray wire and a lower voltage checking brn/wht to ground?

I'm afraid I do not have the correct wiring diagram and the wire colors do not seem to match the schematic that I was using. I have to see if I can find the correct drawing.
 

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Discussion Starter #13
I think the wiring is similar to above. I just took a few pics. A/B/C/D are Brown/white, Brown.White, Grey and Grey respectively. This is on the dif side. these correspond to red, red, brown, brown on the power side. When I say I measured between them, this is exactly what I did, I measure on the power side between red and brown and (A/C. A/D and B/C and C/D) the ~9v was on A/D and B/D, this was with ignition on and bike in Low and AWD on. This is what I take from the above test sequence diagram you provided. I really need a schematic to figure out where the brown (D) is going? If its going to ground, then this is my problem as I am only getting 9 volts on that brown with either of the two reds, but maybe that's what it is supposed to be?

Also the first pic show one of the reds with a stripe and one of the browns with a stripe, not sure if these are supposed to be measured as pairs or not. the other two may be stripped as well, I'm not sure
IMG_8787.JPG
IMG_8786.JPG
IMG_8785.JPG

137852
137853
137854
 

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Discussion Starter #14
I bought a manual. What I was doing was somewhat correct. I have 12v on the red and battery neg. (AWD) and the same on the red ADC. The AWD coil is 20.6 ohms between (B/C) and the ADC coil is at 12.2 ohms as measured between A/D. Nominal is 23.0 and 12.49 respectively, +/- 4 ohms, (although in the electrical section it states the AWD coil resistance at 25 +/- 5% (1.2ohms) contradictory to the above). So I don't know what to believe, one way I'm OK, the other I'm out a lot of money.

The AWD is supposed to engage when ground is supplied through the brown/white, which I tested yesterday at 12v with the red power. So I meet the electrical voltage, I have the correct (debatable) resistance, so electrically I'm fine. I guess I'm removing and tearing down the dif and having a look.

Any thoughts before I remove the dif and disassemble?

Below from the manual,,,,,,,,,,,,,,,

ALL WHEEL DRIVE (AWD) AND ADC COILS
OPERATION OVERVIEW
• Key on power is supplied to the AWD hub coil from terminal 23 in the fuse block, on the RED/GREEN wire. The AWD hub coil is engaged when ground is supplied on the BROWN/WHITE circuit for the AWD hub coil.
• Ground is provided through the ECU, the BROWN/WHITE circuit terminates at ECU pin 217.
• The ECU must see all required operating conditions (rpm in range, correct gear range) and an AWD switch signal to activate. It then communicates with the Instrument Cluster via CAN bus to display the AWD icon.
DIAGNOSING SYSTEM FAILURES
• Verify the AWD/ADC switch is functional. This can be accomplished by seeing if the AWD indicator comes on when the switch is turned on and all AWD criteria are met.
• Verify the AWD/ADC Coil circuit(s).
1. Check the DRIVE fuse.
2. Disconnect the AWD/ADC hub coil connector at the front gear case.
3. Connect the clamp lead of your test light to battery negative (:cool:.
NOTICE
The BROWN/WHITE (BN/WH) and BROWN/YELLOW (BN/YE) wires in the AWD/ADC hub coil connector are grounds, but they are ECU controlled. They will not be consistent and reliable for either this test or trying to read voltage with a DVOM. Only use 8- at the battery or a known good chassis ground for testing this and the ADC circuit.
4. Turn the key on, engine off.
5. Probe the RED/GREEN (RD/GN)wire in terminal C or D (C is AWD, D is for ADC) on the main harness side.
If it illuminates, the circuit is verified up to the front gearcase.
If not, you have an open. Check continuity from the AWD/ADC connector RD/GN in terminal C or D (C for AWD, D for ADC) back to the DRIVE fuse.
If all checked good, test continuity from the BN/WH in terminal B of the front gearcase connector to terminal 17 in the ECU connector (circuit E217) if the issue is with AWD. If the issue is with ADC, check the BN/YE back to ECU terminal 49 (circuit E249).
 
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