I’m having issue recently with the 4wd on my 2015 500FM Foreman. I had the ATV out hunting on a frosty day and after switching between 2wd and 4wd/lock a several times successfully, the 4wd suddenly failed to engage (while in 4wd). After flipping the switch several times and restarting the bike the 4wd engaged and I was able to get myself unstuck and out of the country.
Since then the ATV has failed to shift from 2wd to 4wd or vice versa. I have managed to engage and disengage 4wd several times after flipping the handle bar switch numerous times and turning the ignition off and on. The 4WD and Diff Lock indicators are now flashing continuously on the display (9 long and 1 short blink – error code 91 in the service manual). That said the error codes and possible solutions in the manual are vague at best.
I have taken apart the handle bar switch, it looks OK, no corrosion that I could see. I physically checked the relays to ensure they had not come loose, they looked OK as well, I can hear them click when I use the switch. I blew out the connector on the actuator and applied some dielectric grease, no corrosion or water noticed there. Finally, I removed the cover off of the actuator, I attempted multiple times to engage and disengage 4wd (50-60 times), cycling the switch and the ignition. The actuator engaged only twice during these attempts, repeating the process did nothing, it appeared to be at random.
Anyone have ideas on where to go next? I have called ~10 Honda dealers and none of them have seen this issue before, they feel the system is fairly "bulletproof". I think that it is likely an actuator issue, however at a replacement cost of ~$350, I thought it would be worth asking.
I apologize for the length of the post. Hopefully I have given enough information – Thanks in advance.
HondaNL
