Modern Vespa

Hello everyone, as many of you know, a few months ago (a lot more that I expect at first moment) I embarked on converting my very new (1100km on the clock) 500HPE Sport Advanced (US version) with reverse to 530cc.

After many setbacks both due to the lack of accurate information and for work reasons that prevent me from dedicating myself to the motorcycle as I would like (almost 7x24 ha ha ha) everything mechanical is now working perfectly, but the reverse stopped working at some point. Then one day it was working fine again (we assumed it was a loose connector after lowering and raising the engine several times and didn't pay any more attention to it), we finished some other details and when we were about to put everything back together (covers and aesthetic parts), it stopped working again, and don't like to work from that moment.

The fuses and cables have been checked to the extent that we have managed to understand the electrical diagram of the motorcycle (I have the electrical wiring diagram as well as the workshop manual) but we have not been able to find the problem, and unfortunately in my country there is no Vespa-Piaggio dealer that could have a PADS to see if it provides more information than what the Diagnostic Tool that I have (OBDSTAR iScan) offers me, although I still attach here the image of the errors it returns.

To put into context, the reverse system uses a total of 3 relays, two under the seat on the side, large, similar to those used in the X9 for starting, and a small one under the instrument panel. In theory, if I understand the electrical diagram correctly, when activating the reverse (switch on the dashboard) the ECU sends a positive signal through a blue wire to one of the relays and at the same time to a buzzer to give an acoustic signal that it is in reverse and allow pass of + to the next relay (thick red wire), then pressing the start button activates the electric reverse motor and the motorcycle moves backwards. At some point (and this is one of my doubts since I have nowhere to see it, if someone with a MP3 with reverse can confirm the moment be very appreciated) a solenoid is activated that disengages the transmission and allows the electric motor to move the wheel. But when I activate the reverse switch nothing is happening (we check the switch and it switch between 2 cables (Light Blue and Grey/Black) a negative signal correctly), the buzzer is not activated or anything and if I measure the signal on the blue cable, there is nothing

We tried feeding the blue wire directly and the buzzer activates and the relay but not the other components, we tried feeding the relays directly and nothing, we tested the solenoid by hand and it activates without problems (inclusive at the relay side so the test is better), we tested the motor and it also activates without problems, but the total assembly does not work.

It is as if the ECU assumes that there is a problem and that is why it does not allow the other signals to pass, a safety stop or something like that (even in the electrical diagram it is seen that the solenoid receives or sends a signal to the tip over sensor, but the motorcycle turn on and go).

I attach the image of the scanner, the errors are P0812 and P1314, but they talk about a potentiometer that I cannot find or see anywhere

I can share the electrical diagram if jimc helps me place it on the wiki, since the pdf is large.

Right now I'm out of ideas and I need fresh minds to see if I can get out of this quagmire.

Any help is welcome, regards

What is the RPM, my idle RPM is 1650 at working temp and I can go to reverse.

When cold and warming op the RPM is ca 1750-1800 and I can't go to reverse.

Interesting comment, I should check that out exactly, I never see that as it is working.

When you say "I can't go to reverse" but you put the button on R does the buzzer sound or does it just not work when you press the start button and it doesn't go in reverse?

It just does not work if the RPM is over 1680, no buzzer nothing.

BJN that is a very good comment, thank you!

Can yo do a test for me? if you pass the key to ON position without start the engine but having the Kill switch in RUN the buzzer sounds? The reverse works (I think to work the reverse as press the start button needs the engine in idle but not sure what happens with the engine off)?

Ignition on, kill switch in run, D-R switched to reverse. No buzzer or reverse operation.
Engine must be idling (below 1680 RPM) reverse selected and starter switch operated to go in reverse, buzzer sound continues as long as "R" is selected.

BJN these data about regular operation are the best of the best, the bike has been disassembled for so long that I don't have many of these things in my memory and they can help me a lot to diagnose the problem. Thank you so much

Now the only thing about normal operation that I have to clarify is if the solenoid is activated as soon as the motorcycle is put in reverse with the D/R switch in the dashboard or is it activated at the same time that the start button is push and is activated the reverse electric motor (when pressing the button to move backwards).

Not sure if this can be see without remove the external cover

long shot here, I removed the entire front plastic and when I reinstalled everything I must have not made sure the reverse switch connector firmly attached as it worked before buttoning up everything and then it didn't. Turned out that the connection to the switch wasn't all the way in so no connection.

We already considered that possibility, we even did the test without the switch (in case it had a problem) and we put a jumper to activate manual and nothing.

But thanks for the observation, they are always useful

Maybe someone with a MP3 with reverse know the answer for this?

Worth a watch I imagine

Thank you, but it don't answer the solenoid activation moment

Maybe this video, at 12 mins 02 seems the revs are at 1500 after he has had a good ride down the highway

Exactly, sounds as the RPM take a very important part in the equation

Just for infor dariusz, I fired up my 500 2019 today, battery had been maintained all winter, topped up every month or so, it fired up straight away couple of shakes at first, then put it into reverse to get out of garage, no warming up or anything, it just worked, so not sure now, RPM has anything to do with it, but this is a 500 obviously, a good old battletank.

Very interesting, it seems that in your case the RPM does not have much importance, of course, I imagine up to a maximum limit (Maybe <2000 or some like that)

Yes highly possible, hope it helped a little

Any comment helps, thanks to all who have provided comments.

There are times when a comment that seems insignificant actually leads to a solution.

type ecu/Throttlebody is maybe the issue

there are 4 different ecu's for 500 hpe cm310904 cm310905 cm860904 and a 905 a 5 is for a advanced the other one without reverse

The 530 uses a CM310901 didn't look add the wiring but could be the pin out on this one is different if you using a cableharness from a 500

ECU type? Don't make sense for me as is the one that comes with the bike (I don't change it) and before I start the disassembly it works perfect.

UPDATE:

Trying to unite all the information collected, including the test that we do, I think we have narrowed the problem down to two possibilities:

1. The solenoid that is not correctly reporting its status to the ECU (I read that it has a linear sensor that I assume tells the ECU if it is closed or extended)
2. The ECU that for some reason is not processing the signals correctly and does not send the activation signals.

I have managed to activate both the solenoid and the reverse motor by hand, even using the relays that control them, so it must be a signal where the ECU does not allow activation of the system.
The point is to know if the ECU are not allowing it because it cannot process the signal or because it are not receiving what expect to receive or is not receiving any at all. This seems to me to be in line with the diagnostic results that says about a potentiometer that I could not understand what it was at first time, but now I assume it is the linear sensor (can be named a potentiometer).

On Saturday I am going to check the wirings between the solenoid and the ECU in the signals part (pin 25 on ECU vs 2 and 6 in the solenoid, and 23 on ECU vs 4 on the solenoid) to see if there is any interruption, if there is not, I will remove the solenoid to see if, for example, it is not returning to the point that the ECU expects. or something like that. I hope it is a wire, something repairable, the solenoid is much more expensive than I would have expected (more than 400 EUR) so I hope I don't have to change it.

I will continue reporting when I have new findings

When you actually put in reverse does the reverse camera show up ?

Camera? Mine is not a 530 is a 2022 500HPE but with the 530 cylinder 😉 so basically the exact one as yours 2019

Now i get it, I would be looking at cable harness then.

I deserve that it was late I meant pins

UPDATE:

On Saturday (yesterday) we did the tests that were planned, all the cables that go from the solenoid to the ECU have continuity without problems, so the suspect is still the solenoid potentiometer, that are not giving the ECU the correct information and the ECU disables the entire system as a precaution.

I discovered that my OBDSTAR scanner has a function that allows to "calibrate" the solenoid potentiometer (our joy was short-lived), we did the process 3 times but at the end it tells us that it can't finish correctly
The interesting thing is that during the calibration process the ECU activates the reverse, both the solenoid and the motor, using only natural elements of the motorcycle (for example, in one part it asks that the start button be left pressed and does the activation, the wheel move backwards etc), so I guess (if someone thinks differently I'm open to ideas) the entire system is fine, except for the solenoid assembly.

I have the solenoid in my hands outside the bike at home now, the "motor" works well, since it pushes and retracts. The potentiometer is a COLVERN LM10/3M29 1K0M 298 21 but I can't get any kind of instructions to know how to do a test on him to be 100% sure that he is fine or not. If there is someone who knows how to test it and sheds light on it, I would appreciate.

My alternatives at this point are to take a risk and buy only the potentiometer (it is not easy to get the 1KOhm one) which if it is in China, USA or Europe the cost is between $50 and $140 + shipping, and take the risk that it is not exactly the one that the ECU expect to see and stay the same problem, or buy the complete set (solenoid + potentiometer) at Piaggio and spend about $370 to $450 (I think this alternative would be safe, but super expensive).

This setback delays me from getting the bike 100% operational again, since whatever the alternative, it is at least 2-3 weeks to wait for the parts.

Any comments and help is well appreciated

Considering that the bike and its components are near new, and were tested at the factory I doubt the problem lies there.

What I trust less is your OBD scanner. Does it support the MP3 500 Advanced version specifically? Or is it one of those generic scanners?

However, IF it is the solenoid and pot then replacement of the entire assembly with a new genuine Piaggio is the only smart choice.

Do this piecemeal and you'll be hurting on the multiple shipping costs and delays.

Bottom line: verify the scanner is not spitting out false codes (if it is not compatible with the Advanced version).

It support it directly (>2019), and a as a extra we test all connections one by one not only to the solenoid but all the cables with signals or power to all the components associated to the reverse

And yes, as is brand new I don't expect it is wrong, but in the shop is a yourban 2020 (less than 7k km on the clock) with the tilt lock sensor damaged and is worst as Piaggio don't sell it alone but as as part of the whole system. So I can't trust in the factory checks or reliability of the electric parts 😟

In that case, start shopping for a complete new genuine Piaggio assembly.

Is a way, but I like to test the electronic component so I can be 100% sure before spend +150 or +$500, and this is why I ask of someone know how to test it

If you can locate somebody who has the Piaggio PADS system, then you may be able to test & verify it

Just seems very unusual that this issue started after the mods. You may want to considering undoing the mods one by one and see if anything changes.

Can be the ideal situation, but no PADS system here in my country 😟 Agree, but all shows fine, my best bet is that in some moment a damage can happens, no idea when or how, but that's what I can assume

Just a wildcard have you looked at the power of the part that is fitted on a 530, maybe they are not the same power and this could be why an error is being thrown.

Good comment, but I believe not. The 530 parts are only associated with the cylinder and the crankshaft not close to the CVT assembly, so not sound to me as any relation with. And the ECU and CVT is the regular one from the 500 🤷🏻‍♂️

What about towing/trailering the bike to the nearest country that has a Piaggio presence?

Just throwing ideas out. No idea how feasible this might be

If is EU I think can be a option, but in LATAM between distances and other factors can cost maybe $2-3K easy 😟

Another thought does your scanner have the latest software updates, and if yes, then maybe see if someone close to you has another scanner to try if no pads available, it might eliminate if it is a scanner problem also.

Update:

After wait for the reverse solenoid to arrive, I install it Yesterday, no luck, the problem continue, exactly the same errors as before and reverse still doesn't work.

Now my only options are or that the ECU comes bad or no idea what else check

The strangest thing is that if I run the solenoid calibration process on the scanner, it activates the reverse (motor, solenoid, etc.) but when finished it says that there was a failure to complete. I don't know what to think, my instinct tells me that if it were an ECU problem, shouldn't I be able to do the test and activate things? Don't know