[MrFixit]

Hello to all, New member,Trying to resurrect a 2002 TRX350FE2A. Just some background first.
I have a new battery. The clutch is adjusted. The meter is powered. All connectors have been cleaned and dielectric grease applied. The speedometer always reads 0mph. The gear indicator is always blank, except when you unplug the speed sensor. With the key on engine off, speed sensor unplugged, I can shift through the gears and R,N, & 1-5 all show on the meter. When you ride it slow it will shift fine, but if you ride it normal, shifting will lock up until the key is switched off and back on, then it will work again.
First tests: Speed sensor; measured voltage on the harness side between BL/BU+and G -.
Manual says I should read battery voltage. I am only reading a little over 4.69 vdc. Should I be reading more than 12 vdc on the harness side between BL/BU + and G - ???
With jumpers between the harness connector and the speed sensor connector, KOEO, I am measuring voltage between the PK/G + and G - reading 5.16 vdc constantly, while slowly turning the wheels. No pulse voltage. I have installed a NEW speed sensor and it tests the same.
Usually I can figure this stuff out but I don't have the experience with these.
I would appreciate your insight. :nerd

 

[MrFixit]

Any questions?
Any suggestion?:nerd:nerd
Any one?

 

[Jeepwm69]

No idea.

Sounds like you eliminated a bad speed sensor. Almost sounds like a problem with the ECU but that's a pricey part to buy and throw at a bike if it's not the problem.

The display on the 350's is just a display, so the bike will work without it.

I converted my 350ES to a footshift so I wouldn't have to deal with electrical gremlins. LOL

 

[MrFixit]

No idea.

The display on the 350's is just a display, so the bike will work without it.

So your saying I could unplug the meter and the gears will still shift as they do now?

 

[MrFixit]

Do you know if I should be reading more than 12 vdc on the harness side between BL/BU + and G - while doing the speed sensor test???
That voltage appears to be coming from the meter. I just don't know if it is supposed to be 5+vdc or 12+vdc.
I don't have one to compare so if anyone has one that works correctly, could you take a voltage reading for me.
I was leaning hard toward a bad meter but if what you say is true I am out in the really tall weed with this thing.
If I follow the flow chart the speed sensor and the meter have to function properly before even getting into the ESP flowchart.
I will do some more testing, but the speed sensor test did not pass. I have no pulsed 0-5 volts.
Thanks

 

[MrFixit]

Since this thing will shift perfect while putting around slowly and doesn't quit working until the RPMs get up to a certain point, I am thinking about cutting the RPM input wire going to The ECU the BU/Y wire labeled NEPV on the wiring print.
Has anyone tried this to keep the electric shift working at higher RPMs???

 

[misterclean59]

Sorry but I have no info to help. There are some here that are qualified but evidently they haven't seen this post yet.

 

[Carolynskii]

Has every characteristic of a bad speed sensor. But I’m confused .... did you install a new speed sensor on the bike or not?
Also, did you install a new angle sensor yet?
Not sure why you would cut a wire when unplugging the sensor would go the same thing. Welcome to the forum!

 

[MrFixit]

It took a little while to convince myself, but I went ahead and cut the RPM input wire going to The ECU, the BU/Y wire labeled NEPV on the wiring print. I read somewhere in my research that if the ECU doesn't have a speed sensor input before the RPMs get to a certain point it would shut down the ESP. With the KOEO I was able to shift through all the gears, so I deduced the ECU does't need any RPM input to shift. I think this RPM input to the ECU is just to keep you from shifting gears if the RPMs are to high to shift without tearing up something. I had to leave the speed sensor unplugged to have gear indication. I suspect a problem with the meter but if you can't find one this is a good work around. Took it on a test ride and everything works except the speedometer, but I don't need to know how fast I am going, I am just glad to be going and electrically shifting again.

:yeahbaby01::icon_ lala::icon_ banana:
:hail:

 

[MrFixit]

Has every characteristic of a bad speed sensor. But I’m confused .... did you install a new speed sensor on the bike or not?
Also, did you install a new angle sensor yet?

Yes purchase brand new oem and it tested same as old one. Did not work.

Not sure why you would cut a wire when unplugging the sensor would go the same thing. Welcome to the forum!

The wire I cut was at the ECM 22pin connector. The BU/Y wire labeled NEPV on the wiring print. This is the way I think this part of the circuit works.
The ignition pulse generator sends a pulse to the ECM and the ignition control module. The ignition control module uses this pulse for ignition firing. The ECM uses this pulse to determine the RPMs. Since I was able to shift without the engine running I deduced the ECM does not need this pulse to enable shifting. It uses high RPMs to disable shifting or RPMs without Speed sensor input to disable shifting.
The best evidence my assumption is true is that by cutting the wire, I am able to once again electrically shift, although I do not have speedometer reading because the speed sensor has to remain unplugged to have gear indication.

 

[MrFixit]

I think my whole problem has been the meter. I have been trying to purchase one, but they have been on back order for at least six months. I think the voltage coming to the speed sensor from the meter is too low. When the speed sensor is plugged in I lose gear indication on the meter. I think plugging in the speed sensor is taxing the voltage supply and the gear indication is part of that voltage. Once it drops below the 5 vdc necessary for the LCDs of the gear indicator to work, they disappear.
Any thought about how this works?:nerd
Does anyone have any information or know of a website with the necessary information to troubleshoot and repair these Honda combo meters?:hail:
Thanks

 

[Carolynskii]

Do you have a link to where you got your speed sensor or did you get it from Honda?

 

[MrFixit]

Do you have a link to where you got your speed sensor or did you get it from Honda?

I purchased it from a Honda dealership in Utah over the phone and they just mailed it to me. They still had one in stock after they became discontinued. I will probably be putting this one on eBay as soon as I am sure I am not going to need it.
Thanks

 

[retro]

I just skimmed through your thread, so please forgive me if I'm wrong...? but if I read your posts right, that speed sensor did not pass any of its tests. You gotta fix that IMO, because the speed sensor is a required input for both the ECM and for the display meter.

Take the speed sensor through another test probing both sides of its connector, per the manual. Start by measuring its supply voltage and ground. Then check for 5 volts pulse voltage as the output shaft is being turned. Also inspect the reluctor on the output shaft for damage, or for magnetized metal particles clinging to it. See the attachment.

 

[MrFixit]

I just skimmed through your thread, so please forgive me if I'm wrong...? but if I read your posts right, that speed sensor did not pass any of its tests. You gotta fix that IMO, because the speed sensor is a required input for both the ECM and for the display meter.

Take the speed sensor through another test probing both sides of its connector, per the manual. Start by measuring its supply voltage and ground. Then check for 5 volts pulse voltage as the output shaft is being turned. Also inspect the reluctor on the output shaft for damage, or for magnetized metal particles clinging to it. See the attachment.

I have installed a NEW OEM speed sensor and it also fails the test in the same manner, no pulse voltage. I have a constant >5vdc; no pulse. I have inspected the reluctor and found it clean and undamaged. On the 2000-2002 models the speed sensors supply voltage is provided by the Meter. Do you know what the supply voltage should be? I believe the supply voltage on mine is low coming from the meter. Since I am unable to purchase one to install to verify my suspicions, removing the RPM input from the ECU is a work around until I can find a meter to purchase.
If I knew more about how this system is supposed to properly work, I would be more likely to pinpoint the exact problem(s). I did figure out that mine was shutting down the ESP because there was no speed sensor input to the ECU when the RPMs exceeded a certain value. I have read several posts where people state that they are able to shift while driving slowly, but once they drive it normally, shifting is disabled. Some of these people have fixed this system by replacing the speed sensor, but I have this symptom in conjunction with the gear indication being completely blank; not even dashes. When I unplug the speed sensor the gear indication reappears. I feel I have multiple problems emanating from the meter. I have a new fully charged battery, I have tested all the other components to the best of my knowledge and all have checked good. I have inspected the pins, cleaned and applied dielectric grease to all connectors. I have cleaned all ground connections and applied no oxide grease.
I wish I had more information on trouble shooting and repairing the meter.
Any suggestions???:nerd:nerd

 

[retro]

I have installed a NEW OEM speed sensor and it also fails the test in the same manner, no pulse voltage. I have a constant >5vdc; no pulse. I have inspected the reluctor and found it clean and undamaged.

Measure the voltage between the Black/blue (+) and Green (−) wire terminals at the harness side 3P connector. There should be battery voltage with the ignition switch ON. If there is no voltage, check for open circuit in the Black/Blue (+) wire by moving your multimeter lead from the Green wire (-) to an engine ground. If still no battery voltage, move your multimeter upstream and check for battery voltage supply at the fuse box... that wire could be broken somewhere or the display meter/fuse connectors might be dirty.

But if you observe battery voltage using the motor for a ground, there is an open circuit in the ground somewhere. Do NOT ground that green wire in an effort to avoid fixing it, because that ground has several unions inside the main wiring harness controlling other components. Refer to the attachments for reference for all of these tests.

IF your supply voltage is normal following all of the above tests, plug the speed sensor back in and measure for the 5 volts pulse voltage by turning the ignition switch on and rotating the rear wheels. You will need to make a test adapter for this test, or buy one.

If the supply voltage and ground test good but the speed sensor fails the pulse voltage test, the sensor is bad. Replace it.

On the 2000-2002 models the speed sensors supply voltage is provided by the Meter. Do you know what the supply voltage should be? I believe the supply voltage on mine is low coming from the meter. Since I am unable to purchase one to install to verify my suspicions, removing the RPM input from the ECU is a work around until I can find a meter to purchase.

False.
The supply voltage for both the display meter and the speed sensor are switched by the ignition switch and are fused in the fuse box through the Black/Brown wire. See the wiring diagram attachment.

If I knew more about how this system is supposed to properly work, I would be more likely to pinpoint the exact problem(s). I did figure out that mine was shutting down the ESP because there was no speed sensor input to the ECU when the RPMs exceeded a certain value. I have read several posts where people state that they are able to shift while driving slowly, but once they drive it normally, shifting is disabled. Some of these people have fixed this system by replacing the speed sensor, but I have this symptom in conjunction with the gear indication being completely blank; not even dashes. When I unplug the speed sensor the gear indication reappears. I feel I have multiple problems emanating from the meter. I have a new fully charged battery, I have tested all the other components to the best of my knowledge and all have checked good. I have inspected the pins, cleaned and applied dielectric grease to all connectors. I have cleaned all ground connections and applied no oxide grease.
I wish I had more information on trouble shooting and repairing the meter.
Any suggestions???:nerd:nerd

The ES system on the early Ranchers is very basic and very dumb. The display meter is just a client... it is just a simple display. It does not power or control anything. It just sits there displaying data coming in through its inputs.

Do not ever make any assumptions when working on electrical gremlins. Our minds become our worse enemy whenever we form assumptions.

Follow up and let us know what you find out. If you have any questions hollar!

 

[retro]

Additional basic info attached in case you need it. I reposted the system inputs/outputs diagram as well.

Remember, every input most function properly, else the outputs will fail. The speed sensor circuit is an input... while the display meter is not.

 

[MrFixit]

Measure the voltage between the Black/blue (+) and Green (−) wire terminals at the harness side 3P connector. There should be battery voltage with the ignition switch ON.

This is one of the questions I have, what exactly is this voltage supposed to be. I am not reading FULL battery voltage. I am only reading 4.69vdc.

On the 2000-2002 models the speed sensors supply voltage is provided by the Meter. Do you know what the supply voltage should be? I believe the supply voltage on mine is low coming from the meter. Since I am unable to purchase one to install to verify my suspicions, removing the RPM input from the ECU is a work around until I can find a meter to purchase.

False.
The supply voltage for both the display meter and the speed sensor are switched by the ignition switch and are fused in the fuse box through the Black/Brown wire. See the wiring diagram attachment.

Unless I am mistaken, from what I can make of the circuit, the fused power goes to the meter on the Black/Brown and then from the meter to the speed sensor on the Black/Blue. On the 2003 model that changed and is powered from the ECU on the Black/Blue.

The ES system on the early Ranchers is very basic and very dumb. The display meter is just a client... it is just a simple display. It does not power or control anything. It just sits there displaying data coming in through its inputs.

With the meter unplugged I have no voltage on the Black/Blue wire at the speed sensor connector, therefore the meter is in the voltage supply circuit of the speed sensor. I just don't know if this voltage is supposed to be just above 5vdc or just above 12vdc. In either case the voltage I am reading is low.

Do not ever make any assumptions when working on electrical gremlins. Our minds become our worse enemy whenever we form assumptions.

Electrical gremlins are aggravating to say the least on any vehicle. Intermittent electrical gremlins can be worse.
I know I don't have the hands-on experience that many of you may have with ATVs, so while I am learning, I must form some kind of hypothesis that must be realized or discredited through new information, hands-on testing, and symptom observations rather than waiting on someone to spoon feed me the information. Whenever I have a revelation I will be sure to post my results.
I appreciate you and any suggestions, directions, and information you will convey.:smile

 

[MrFixit]

Remember, every input most function properly, else the outputs will fail. The speed sensor circuit is an input... while the display meter is not.

Definitely the speed sensor is a necessary input for the proper function of the ESP. In order to have this output to the ESP, the voltage going to the speed sensor must be within a certain voltage range to correctly operate. I don't know what this value is supposed to be on a fully functioning ESP system. Without the correct voltage there will be no output to the ESP system from the speed sensor. There is 12vdc supplied to the meter on the Red wire 30A Main fuse. I may be wrong but I think the meter transforms the 12vdc to 5vdc for it's own use and supplies that same 5vdc to the speed sensor. I am only reading 4.69vdc which is below the 5vdc threshold I believe is necessary for it to work. The manual says Black/Blue to Green should read battery voltage and that is what everyone quotes. While originally troubleshooting the speed sensor, when I read Battery Voltage, I was thinking the supplied battery voltage of above 12vdc, but after looking at the circuit I am leaning toward a voltage just above 5vdc.
If someone has a working 2000-2003 ESP I would appreciate a voltage check at the speed sensor connector, harness side, between the Black/Blue wire and the Green wire with KOEO.
The 2003 may have the same voltage as the 2000-2002. It would just be supplied from the ECU rather than from the meter.
I thank you for your insights.:nerd

 

[retro]

Unless I am mistaken, from what I can make of the circuit, the fused power goes to the meter on the Black/Brown and then from the meter to the speed sensor on the Black/Blue. On the 2003 model that changed and is powered from the ECU on the Black/Blue.

It sounds like you are not understanding the wiring schematic right...? Look at these two photos below of the display meter schema and fuse box... see the Power bus all tied together in the meter diagram? There is the Bl/Br +12v supply and Bl/Bu +12 supply for the speed sensor tied together... also Lg/R, Bu/R and Gr tied together with the Bl/Br wire supplying positive voltage for the indicator LEDs, plus the Bl/Br wire supplies +12v to the meter CPU circuit.

That is called a Power Bus circuit.... one +12v supply wire energizing several sub-circuits/components in the system. It would be foolish and wasteful to run separate +12v wires to supply power for each of those circuits, wouldn't it...

========================

=============

With the meter unplugged I have no voltage on the Black/Blue wire at the speed sensor connector, therefore the meter is in the voltage supply circuit of the speed sensor. I just don't know if this voltage is supposed to be just above 5vdc or just above 12vdc. In either case the voltage I am reading is low.

See the above... ^^^ The Black/Blue wire supplying input voltage for the speed sensor is tied directly to the Black/Brown +12v supply coming from the fuse box (15a lighting circuit), which is switched through the ignition switch via the Pink wire. Refer to the wiring diagram I posted earlier to see that complete +12v power supply circuit which originates at the battery.

I have a 2000 Rancher ES torn down for a winter maintenance session, so despite the fact that the service manual specs have been known/proven to be correct for over 18 years now, I went out and put a multimeter on the Bl/Bu connector pin inside my speed sensor plug with the ignition switch ON. The resulting voltage reading was just under battery voltage, which is normal and expected due to the resistance through my 15 foot long jumper cables and throughout the bike's wiring harness, causing a slight voltage drop.

Electrical gremlins are aggravating to say the least on any vehicle. Intermittent electrical gremlins can be worse.
I know I don't have the hands-on experience that many of you may have with ATVs, so while I am learning, I must form some kind of hypothesis that must be realized or discredited through new information, hands-on testing, and symptom observations rather than waiting on someone to spoon feed me the information. Whenever I have a revelation I will be sure to post my results.
I appreciate you and any suggestions, directions, and information you will convey.:smile

You don't need to invent an excuse for why it does not work. All is already known and fully understood. You've got to trace back through the wiring harness to find the fault. DO NOT take the display meter apart, that has nothing to do with your issue. You've got the wiring diagram... check voltage on both sides of the 15 amp lighting fuse. Then check the relevant wire pairs at the ignition switch... finally trace between the battery and the ignition switch. You'll find a voltage gap in it if you trace back through the circuit methodically.

Have you or anyone else ever hacked into the wiring to add accessories? Are the harnesses damaged anywhere? Any corrosion in connectors? If so, revisit those splices/damages first.

Keep a smile on...