DIY MEFI5 scanner / code reset tool

[loudsubz]

Evening everyone.

Over the past 6 months or so I have been on a quest to

a) Figure out what my CEL code was on my 2010 Moomba LSV
b) Build a solution to pull codes / erase codes on MEFI 5 on a budget
c) Learn a thing or two in the process
d) SHARE MY FINDINGS with this wonderful group.

With that said, I scoured many posts on different forums trying to figure out if there was an affordable solution. I came to many dead ends when many responded "no" or there's only XYZ who make one and it's $$$.

I figured as much as we all know what BOAT stands for, and the aftermarket isn't as strong for boats as it is for cars so you won't see $15 OBD2 scanners for boats pop up on amazon.

In my search I found some technical posts on different forums that mentioned the protocol used for most boats was J1939 on the MEFI5 system. I started searching around and realized that it was very similar to OBD2 that it was just a matter of finding the PID and SPN info to decipher what the code means and investigate it from there.

After finding that tidbit of info, I went down the J1939 protocol search and was bound to find a way to use a standard OBD2 scanner to read these J1939 codes.

After realizing that J1939 is very common in the heavy duty bus / truck market and finding those scanners were just as expensive for one that was guaranteed to work I started down the road of "apps" for the phone / tablet.

There were many that claimed to be able to use your standard ELM327 OBD2 module to convert the signal so it could read on the J1939 network but many failed to connect or not enough support for a general "J1939 reader"

I finally stumbled upon a basic J1939OBD app on the Apple App Store. It worked well enough that it connected to my home made J1939 adapter using a basic ELM327 Wifi module (so I could use the app on my apple Iphone) and success, it connected to the engine PCM, was able to pull a code and successfully clear the code. I was stoked.

I wouldn't say the app is polished enough for prime time, but for anyone just needing to see the code and clear the CEL this app worked for me.

The app is linked here:

https://apps.apple.com/sa/app/j1939obd/id1453435912

I made my own OBD2 to MEFI 5 adapter, but you can always purchase one of these guys for a little money (my parts cost like $15 but I'm in Canada so I didn't want to pay more in shipping to get the pre made harness here vs just buying stuff on amazon and making my own). The connectors are DELPHI GT style and you can buy them on Aliexpress.

https://obd2allinone.com/products/obdmobd.asp

The OBD2 ELM adapter is your basic run of the mill:

https://campaign.aliexpress.com/wow/..._id=1085100208

Here are some pictures of the setup and what it reads in the app. Sometimes it takes awhile to get the connection going (again the app is a little glitchy).

I encourage anyone else with a similar passion to experiment with other apps / adapters and see if we can come up with a solid alternative for MEFI5 for your basic troubleshooting so that more people can keep their boats going on their own without being forced to take it to the dealers.

Pictures below:

https://imgur.com/a/kOJfYqW?s=fbm&fb...qkUo0wzJTLhqW0

HKV0q50.jpg

[MNMoomba]

Thank you loudsubz! I have been looking all over the internet for MEFI 5 code reading solutions and am going to give this a shot. I have a '09 Moomba Mobius XLV (Indmar 325) with a CEL on, comes on after idling across the lake for a bit, when on I have reduced power / rough running. My local dealership is 45 min away and charges $199 min for 1 hr diagnostic (just to hookup & read the codes) + 30 min increments for more $$ if it takes more than 1 hr to diagnose. Do I understand correctly that you went from the 6 pin marine connector (DELPHI GT style) to an OBD2 adapter, and then basically broadcast the signals using the OBD2 ELM wifi adapter to your phone app that reads the J1939 protocol? I may just buy the OBD2 to Marine 6-pin Adapter from OBD diagnostics since in the US its about the same price as ordering the items and making myself. Thanks again & stay tuned!

[loudsubz]

That's correct.

I was actually playing around with another app this weekend that I like even better and does the same thing, only issue is it runs on Android only

https://m.apkpure.com/cummins-fault-...wnload/1.1.2.5

I used the basic ELM327 (fatboy model)

https://www.amazon.com/Bluetooth-Dia...%2C101&sr=8-15

If you're in the USA then that connector is ready to go plug and play.

You simply plug one end into the 6 pin on the engine side and the other side to the elm327 Bluetooth adapter and use the Cummins app to collect data and see what's going on.

[MNMoomba]

Alright I tried it but it unfortunately it did not work… Bought the OBD2 to Marine 6-pin Adapter from OBD diagnostics and the OBD2 ELM wifi adapter, put them together with the 1939OBD iphone app, but it would not ever connect. Retried 4 or 5x, no success. Even tried to purchase the full app as it noted limited functionality to show codes without it but no go… Found another dealer to read my code today (found one that charged less than the others I called)...

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[loudsubz]

Alright I tried it but it unfortunately it did not work… Bought the OBD2 to Marine 6-pin Adapter from OBD diagnostics and the OBD2 ELM wifi adapter, put them together with the 1939OBD iphone app, but it would not ever connect. Retried 4 or 5x, no success. Even tried to purchase the full app as it noted limited functionality to show codes without it but no go… Found another dealer to read my code today (found one that charged less than the others I called)...

IMG_3030.jpg
IMG_3031.jpg
IMG_3032.jpg
IMG_3034.jpg

I've found the app is very picky on how it connects

I found the Cummins Fault advisor to be MUCH BETTER but needs to run on android and use the ELM327 Bluetooh version instead.

I went and did more testing and that J1939OBD app for iphone really takes some finesse in the settings menu to get a solid connection to the ecu (no clue why) but the cummins app works great and shows all the faults and pulls proper engine data.

[loudsubz]

cummins1.jpgcummins2.jpg

[MJHSupra]

Can you clear the codes too?


Sent from my iPhone using Tapatalk

[loudsubz]

Can you clear the codes too?


Sent from my iPhone using Tapatalk

yes you can