Im working on a 2004 trx350TE that belongs to a good freind of mine. Ive got 15 yrs of experience working on ATV's professionally but this electrical issue is quiet a stumper... I believe if he would have brought it to me first instead of his brother life would be good for him/me at this point. The brother hacked all over the harness at every point you can imagine, and if not for that a replacement angle sensor would have more than likely fixed the problem. Now the cutting and hacking is more than likely the cause of the ESP not functioning.
Okay here is some background on troubleshooting already performed. When i got the atv in my pocession the neutral icon "N" would not blink a trouble code. It just stayed lit constantly no blinks. repaired "i thought" all damaged and exposed wire contacting other wires missing insulation i replaced the angle sensor. No change. Started at step one in the ESP trouble shooting section and immediatly found i didnt have voltage at the black/red wire coming out of the ECU per the specs in the manual. Went ahead and followed the rest of the troubleshooting guide just to be thorough even though no voltage reading on that blk/red wire said to replace ECU and continue troubleshooting.
After more checking i finally broke down and ordered a new ECU along with a new angle sensor. Plugged it all up per procedure and nothing.. Nothing as in no shifting, but now the "N" would blink trouble codes. It showed a three blink sequence. If you went into diag mode to view or clear codes the 3 blink angle sensor code was present but also the one blink "ECU writing and recording" code was present. Angle sensor code could be cleared but not the one blink writing and recording code. Pinned-out harness and checked multiple other areas on the atv just to find i had missed a point where the three wires from the angle sensor had bare copper touching where insulation had been hacked upon! After more checking in the book i thought i had shorted out the brand new ECU because of these bare wires so ordered another brand new ECU from honda... Oh and a new angle sensor.. before i plugged in the second brand new ECU i made sure all wiring was repaired. Plugged it up along with new angle sensor with exact same results as the first new ECU. Other things that have been checked: continuity from angle sensor plug to ECU plug, all three wires show okay
Testing angle sensor with a meter "resistance" on and off the ATV.
Checked all major connections, un-plugged and pluged back in. Many other things i cannot recall off the top of my head since this has been such a long project.
Could the gear position sensor be at fault even though it tests fine in each gear with a multimeter?
Is it time to replace the harness even though ive repaired "i believe" everything?
Can someone elaborate on this ECU writing and recording code and can anything else cause this other than a bad ECU?
The jumper wires inside the up/down shift buttons housing had also been hacked on for some reason??? Yes i repaired that also.
Ive worked on quite a few honda ESP issues but im no expert by no means. The usuall methods of figureing this stuff out are almost exhausted, and like we all know some electrical parts can test fine but when replaced fix the problem. Just one of those things. I will be more than happy to give someone more information if the need it to help me with this problem along with things i may have forgot to mention. Believe me or not but it is one of those buddy deals and all my time is just being donated but im good with it because he has no other options with his financial situation. THANKS IN ADVANCE EVERYONE!