Modern Vespa

Hello, I'm a new member here and as of Wednesday a new owner of a 2013 Vespa 300 GTS ie. When I purchased it, it had 960 miles. The store I purchased it from was 40 miles from where I live, so I rode the Vespa 46 miles home. I had no problems and it was a beautiful ride on A1A here in South Florida.

Thursday I took a short ride with no problems. Then my next ride the Check engine light came on, then went off. Then it came on to stay on.

I took it to the dealer here and the computer was showing the error was the battery was being over charged, but the battery was only charged to a little under 12 v.

The dealer told me they spent several hours on it Thursday and Friday and tried everything and they could only get the check engine light to go off when they replace the ECU.

The dealer said they've never heard of an ECU going bad before. The scooter store I purchased the scooter from said they've never heard of an ECU going bad before.

As you can tell from the mileage on this Vespa it was not ridden much over the past few years.

Any suggestions on what could be the problem?

I'm tempted to replace the battery first as I'm thinking it's the original battery. Then replace the voltage regulator as I've read on the posts here that that
is a common problem when the check engine light comes on.

Does the light come on when you rev the motor up and go out when it goes back to idle? If yes you have a bad voltage regulator most likely.
Put scooter on center stand, use a volt meter on the battery and rev the motor, does voltage go over 15 volts, if yes you have a bad regulator.

Should have taken the dealer about 5 minutes to figure that out.

The check engine light stays on, it does not go out when idle.

Find a Battery store or go to Auto Zone or such and have your battery tested.

I have had this happen twice. The first time my yellow light came on all the time. Read ECU and no code was displayed. Turned out to be the heater in the O2 sensor. The second time the light came on when the voltage regulator went bad. My guess is your voltage regulator.

1. A battery under no load should measure between 12.5 and 12.7 Volts when fully charged. So, a little under 12 V is not good. Put the battery on a charger for a bit, then let the battery sit for half an hour and retest the voltage. It should be above 12VDC.

2. I also believe it's probably the Voltage Regulator. Get a hold of a Digital Volt Meter -- even a cheap one from Harbor Freight will do for this, or borrow one. Set it to DC volts, range is usually 30 V.

With the engine running at idle, the voltage across the battery terminals should be about 13 VDC. With the engine revving it should rise to 14.5 V to no more than 15 V.

If it goes higher, it is your Voltage Regulator, and will set off a CEL.

Most likely, but you should test because there is a lot of labor costs for a shop to swap one out.

But he states this too, " it does not go out when idle."
Not going to be putting out too much voltage at idle.

This happened to my car recently. Called my shop. They said to make sure the gas cap was tight. It wasn't. It cleared the light after a 100 miles or so. Can this happen to a vespa as well?

Miguel

No Evap is not monitored by the ECU on these scooters like on cars..

Lucky thing for all of you who have fiddled with your EVAP system.

Talked to the dealer today. They swapped out the battery and voltage regulator and still the check engine light comes on. The only thing that clears the check engine light was swapping out an ECU from another vespa.

If you are paying for this service I would be getting PISSED. It is very obvious they do not understand the process of TESTING stuff.
No over voltage while revving the motor, why in the hell replace the battery or the regular for a check engine light?

Do they have a PADS Diagnostic tool?
After testing the battery and for proper charging that would have been the next logical step is to read the damn codes and work the test procedure related to the code.

+1

This sounds like they do have a diagnostic tool: "the computer was showing the error was the battery was being over charged..." Was this showing any fault codes? I'd follow up on these, especially if they continue after the battery and regulator have been replaced.

I have had this problem a couple of times with my new 2018 GTS300. On a long run it comes on and stays on after stopping and restarting. All fine the next day.

I have checked the battery voltages, and the regulator is fine. It seems to happen only when the engine is very hot - in thick start-stop traffic with the fan switching on and off regularly, and also when belting it down the freeway.

The scooter will be having its first service in a week of so, and I hope the workshop can figure it out.

Mike

What I know about Vespa electrical systems, you could fit in your eye. This video (Robot) seems very good, so I hope it's a help to someone.

Thanks to everyone that has posted about this. The video just posted was very informative.

Here's the latest. Yesterday evening I went by the dealer and he showed me the price for a new ECU. Ouch. Then we learned there was not going to be one available until Jan 2019.

At this point I decided I was going to ride this thing until the part came in. So today I picked up the 300 from the dealer. By the way, my dealer did not charge me anything for all the diagnostic work they did.

When I went for my daily ride, about 12 miles round trip. The CEL (check engine light) went off at idle, then came back on, then at speed of 40 to 50 mph it went off and on, and back off at idle.

Tonight I went on a short ride to the store and the CEL did not come on at all. lets see what tomorrow brings.

I will be getting a volt meter to check the battery myself.

I really do appreciate all the help here.

Today for a 15 mile ride, the Check engine light stayed on all except for the last 2 miles. Then for a shorter ride, the check engine light stayed off the entire time. I will get a voltage meter to see what the numbers say.

2020 Vespa GTS 300 HPE, the shop told me today that I need a new ECU, they cannot get their scan tool to connect and only thing left was to replace the ECU, $750. I did this because my engine light is on, but the scooter runs perfect. Will continue riding with engine light on!