MM3 EGT Reads 3717.9 Degree

[Skywrench]

My MM3 EGT reading is stuck on 3717.9 degrees.

Never changes with truck running or off.

Tried unplugging and plugging back in the OBD plug.

Tried unplugging the mini 4 pin connector from communications module and plugging back in.

Tried disconnecting the two sensor wires from the little EGT interface box and reconnected.

Looked at the wiring and didn’t see anything suspect.

Suspect faulty egt probe but wanted to see if there is anything else I’m missing before I buy another egt kit.

Any help would be greatly appreciated.


2016 3500 Laramie Mega DRW Aisin 3.73

 0 Comment(s)

[Aboshan]

Did it work before or did you just install it?

I had the same issue when I installed mine except the reading was different numbers.

I unplugged the OBD2 and the sensor from the black box, waited 15 min, plugged in the egt sensor then the OBD2 port.

After that I got some new selections for the right box for EGT and it has worked flawlessly.

I had selected one that was for EGT display but it was the wrong one.

 0 Comment(s)

[Skywrench]

It was working fine before.

Maybe I’ll try unplugging the OBD2 plug for 15 mins like you did and see what happens.


2016 3500 Laramie Mega DRW Aisin 3.73

 0 Comment(s)

[AK Bob]

If it still doesn’t work I would give MM3 Power a call tomorrow 1 (208) 346-7707.

They should be able to advise and hopefully sell you individual components to repair.

Please keep us posted.


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, 50 Gallon auxiliary fuel tank.

Sent from my iPad using Tapatalk

 0 Comment(s)

[Aboshan]

If it worked before and suddenly stopped I would agree its more than likely the probe.

Mine wasn't reading the right sensor and showed 932 degrees all the time. I had plugged it in wrong during install and the above is the correct way to get the proper sensor selection.

 0 Comment(s)

[Skywrench]

I called MM3 just now.

The guy that answered the phone said it was shorted out (wires touching) somewhere causing a max reading.

Started asking him about the best way to troubleshoot and realized he didn’t really have a firm grasp of electronics.

I then explained that I had disconnected the 2 probe wires from the egt and the reading of 3717 degrees never changed.

He said he really never tried that so he doesn’t know what it should read that way and they only sell the EGT kit as a complete kit so I can’t just buy individual pieces from MM3.

I decided to grab my meter and check for myself and found that my EGT probe has an open, not a short (zero continuity between thermocouple wires).

When I shorted the probe wires together, I got a reading of 96 degrees on the MM3.

I still think I have a bad probe.

Has anyone had any luck buying just the EGT probe that is compatible with MM3?


2016 3500 Laramie Mega DRW Aisin 3.73

 0 Comment(s)

[RATLIN'HP]

Is it possible to hook the wires to an analog guage? Will that work to see what it reads?

Sent from my SM-A505U using Tapatalk

 0 Comment(s)

[Skywrench]

I’m sure it’s possible if you had the right gauge. I don’t have a gauge though. I should see what voltage it measures. I believe that’s how the gauge works, uses voltage to. determine temperature.


2016 3500 Laramie Mega DRW Aisin 3.73

 0 Comment(s)

[AK Bob]

I called MM3 just now.

The guy that answered the phone said it was shorted out (wires touching) somewhere causing a max reading.

Started asking him about the best way to troubleshoot and realized he didn’t really have a firm grasp of electronics.

I then explained that I had disconnected the 2 probe wires from the egt and the reading of 3717 degrees never changed.

He said he really never tried that so he doesn’t know what it should read that way and they only sell the EGT kit as a complete kit so I can’t just buy individual pieces from MM3.

I decided to grab my meter and check for myself and found that my EGT probe has an open, not a short (zero continuity between thermocouple wires).

When I shorted the probe wires together, I got a reading of 96 degrees on the MM3.

I still think I have a bad probe.

Has anyone had any luck buying just the EGT probe that is compatible with MM3?


2016 3500 Laramie Mega DRW Aisin 3.73

Thanks for the update, at least now we know MM3 Power will only sell the complete probe kit.

So far your troubleshooting makes sense, consistent MM3 readings with the probe disconnected and with wires to the probe reading open, then different MM3 readings with probe wires shorted.

I agree with you either the probe is bad or the wires to the probe are open.

Since the wires and the probe are basically one assembly you will have to replace both.

I did some checking on eBay and Amazon but could only find the complete probe kits and they are for the Smarty Touch.

They are probably compatible, but I don’t know for sure.

Don’t know if it’s worth the savings to find out, although you could send it back.

Please keep us posted.

https://www.amazon.com/Smarty-Tuners.../dp/B07D6WJ17W


2014 RAM 3500 (Aisin) 3.73 4X4 Limited Crew Cab Long Bed DRW. Oil Bypass Filter, 50 Gallon auxiliary fuel tank.

Sent from my iPhone using Tapatalk

 0 Comment(s)

[Skywrench]

Update - after doing a bunch of reading, I am convinced that all I need is a K Type Ungrounded Enclosed thermocouple probe. They have a bunch of cheap ones on Amazon. I decided to take a chance and ordered this one:
https://www.amazon.com/gp/aw/d/B00LC...ws_feature_div
After I received it I checked it with my multimeter and found that it was a grounded thermocouple. The package comes with a card with Chinese writing on it saying who knows what. I decided to try it anyway. When I attached the wires without having it screwed into the exhaust manifold, it read correctly but as soon as it touches the exhaust manifold, the readings drop down to negative 180 degrees and are not stable. On the MM3 calibration screen the MM3 tells me the EGT wires are shorted to ground.
I decided to search for a better thermocouple made by a reputable company. I found one made in the USA by a company called “HGSI The Sensor Connection”. I emailed them asking if their EGT probe was indeed ungrounded. They replied back in less than two hours and confirmed it was ungrounded. Here is the tech sheet on it:
http://thesensorconnection.com/sites...Sheet_Rev5.pdf
I have this on order. I will update again when it arrives. It’s around $60 (shipping and taxes included) but a whole lot cheaper than the $150 kit from MM3/Raceme.


2016 3500 Laramie Mega DRW Aisin 3.73

 0 Comment(s)