Okay y’all I’ve got a doozy for you smart cookies out there! Long story short my 04 rubicon is throwing a code 6 for an issue relating to the angle sensor. It runs and drives great just won’t shift out of first and sputters/limits rpm in reverse. I have tried new oem angle sensor, new battery, new oem shift motor, swapping ECM and display screen with another rubicon, tested brake switch, shift button switch, gear position switch and reverse switch to be good, tested wires from ecm to angle sensor to be good, tested for shift motor lock, but still am having the issue. Any advise would be very appreciated! I will post more details about my testing/diagnostic process below incase anyone wants to read into it but tried to keep this version short for those who don’t.
I found this very clean Rubicon for sale on the classifieds (display was cracked so don’t know true mileage but still has original tires on it) for 2000$ with a snow plow but owner said it wouldn’t shift out of first gear and sputters in reverse. I used to own my own powersports shop/dealer but now I currently am a mechanic at a Honda dealer and just buy and sell used atvs in my spare time so I bought this fourwheeler thinking it would be a easy fix and flip. But boy was I wrong. I’ve spent countless hours trying to diagnose this issue. Luckily I have another 2004 Rubicon that I’ve been able to use for testing and borrowing components. So let’s start with my diagnostic process.
1. Performed visual inspection to check for loose/corroded connections, rubbing wires, loose grounds etc. Didn’t see any visual concerns. Battery tested bad with Honda midtronics tester so I installed a brand new yuasa ytx14-bs. Tested all fuses to be good. Removed and cleaned ground wire junctions with wire wheel.
2. I start in the service manual under the ignition troubleshooting under symptoms with it sputtering in reverse. The book has me test the gear position switch and the reverse switch which test good. I also tested the right hand brake switch since I’ve seen those cause sputtering in reverse before. Tested the up/down shift button switches to be good as well.
3. My display screen had a big crack in it from previous owner and so even though the neutral, reverse, and oil light work, the display doesn’t light up at all so no mph, gear position, odometer and most importantly no ability to retrieve flashing trouble codes. Ran tests in the book to make sure it’s getting power and ground which it was so I think it’s safe to assume the circuit board was damage when the screen got cracked. A new display is discontinued from Honda and couldn’t find a single thing on eBay.
4. I decided to try swapping the display off the other 04 rubicon even though I was a little worried since it was the gps version and mine is not. But after plugging it in it appears everything is working as it should. Went and test drove machine to make sure the speedometer was working and even though I was only able to ride in 1st gear the mph were registering on the screen indicating the speed sensor is functioning properly.
5. The swapped display was just flashing the drive mode and 2 dashes on the screen were the gear position would normally show indicating it’s in limp mode. Performed code retrieval and got the display to flash code 6 indicating a problem relating to the angle sensor. Tried clearing the code and reinitializing the computer multiple times but it would fail and keep bringing back code 6.
6. Went through service manual and tested wiring going from ecu to angle sensor to be good as well as the angle sensor to be good. Tried swapping the angle sensor with a brand new oem one but that didn’t fix it. Tried the one out of the other rubicon just incase and that one failed too. (Made sure to preload the sensor according to the book) From there the book says to replace the ECM. I swapped the known good ECM from the other rubicon but that still didn’t fix it.
7. When first performing the reinitialization process I could hear the shift motor running like it’s supposed to. It did that the first two times I tried to initialize but then the third time it would just make a knocking sound making me think maybe it was a motor lock issue (which should normally cause a code 5 but I kept only getting code 6.) I removed the shift motor and spun the reduction gear to make sure it wasn’t stuck. I unplugged the shift motor and jumped power and ground to reverse the gear direction backwards to other end till I heard it lock. Then I reinstalled shift motor and tried to do the reinitialization again I was able to do it twice before it reached the end of its travel indicated by the knocking noise.
8. Removed angle sensor to see if maybe the shaft was broken but it was not. Something odd I noticed is in the service manual when it shows how to replace and preload the angle sensor, it shows the shaft being at the 3 and 9 o clock position. But mine was at 12 and 6 o clock. While the angle sensor was removed I unplugged the shift motor and jumped power and ground and watched the angle sensor shaft start at the 12 and 6 o clock position and turn about 1/8th of a turn. Then I reverse polarity and made it turn back another 1/8th of a turn. This made me wonder if maybe there was an internal mechanical issue since the angle sensor shaft was only turning 1/8th of a turn lock to lock. So I removed the angle sensor off the other rubicon and did the same test but it also started at the 12 and 6 o clock position and would only turn 1/8th of a turn as well debunking that theory.
So this is where I am stuck at currently. If anyone on here has any bright ideas for me I’m all ears! Luckily working for a Honda dealer I also have access to calling there tech line support so I will try calling them and see if they have any other ideas for me. But if not I may end up having to cut my losses and sell it so I can move on to my other flip projects. Sorry for the long read but I’m trying to document this issue as best as I can in case anyone else has a similar issue in the future.