Odd TPMS Issue?

[mseitz24]

I’m having an odd tpms (I think) issue out of nowhere this morning.

My low tire pressure light on the dash is flickering on and off continuously, and I’m getting the warning dinging nonstop.

My tire pressure is 55 front and 50 rear, and I'm reading fine on the dash. I also have nothing in the messages on the dash menu.

Every other sensor seems to be working fine as far as I can tell: oil temp, oil pressure, coolant temp, boost, etc.

The truck seems to be running as usual.

The only other thing I noticed is that my MM3 is not turning on, and no red or green lights.

It's like it’s not getting any power.

I tried unplugging and plugging it back in, which has fixed similar issues with it in the past, but no luck.

I'm unsure if they’re related, but it’s odd for both to happen simultaneously.

My brother-in-law said a tpms sensor could be going wrong, and I’m taking it to him tonight to scan it.

I was just wondering if anyone else has had a similar problem.

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[watersupply189]

Load test both your batteries.

If one or the other is below 12.6V, replace both of them.

Also, the TPMS could be going dead also.
Without proper voltage, your MM3 and the trucks electronics will do weird stuff.


2016 Ram Laramie 3500, G56, 6.7, CC, 4x4

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[AK Bob]

I’m having an odd tpms (I think) issue out of nowhere this morning.

My low tire pressure light on the dash is flickering on and off continuously, and I’m getting the warning dinging nonstop.

My tire pressure is 55 front and 50 rear, and I'm reading fine on the dash. I also have nothing in the messages on the dash menu.

Every other sensor seems to be working fine as far as I can tell: oil temp, oil pressure, coolant temp, boost, etc.

The truck seems to be running as usual.

The only other thing I noticed is that my MM3 is not turning on, and no red or green lights.

It's like it’s not getting any power.

I tried unplugging and plugging it back in, which has fixed similar issues with it in the past, but no luck.

I'm unsure if they’re related, but it’s odd for both to happen simultaneously.

My brother-in-law said a tpms sensor could be going wrong, and I’m taking it to him tonight to scan it.

I was just wondering if anyone else has had a similar problem.

Having your brother-in-law check the TPMS sensors to see if they are all communicating is a great idea.

Also, have him plug his scan tool into your OBD port to see if it’s working correctly and check all modules for trouble codes.

Meanwhile, as @watersupply189 mentioned, check your batteries and check all the connections at your MM3 monitor and communications module under the dash.

Also, please see the two halves of the communications module if you have the older style.

Please keep us posted.

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[mseitz24]

So it’s something in the MM3.

The TPMS sensors scanned ok.

We unplugged the MM3 from the obd port, and the tire light stopped blinking.

I guess I’ll have to pull everything apart and see if there’s a bad connection or something.

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[jeepmanjr]

Something similar happened to me a couple of years ago.

My MM3 monitor stopped working from one day to the next.

There were no lights and nothing.

I tried everything but no joy.

Frustrated, I sent it to the man who told me the micro USB port was bad.

So I bought a new one and plugged it in, and it has worked flawlessly ever since.

Just FYI, in case you can't narrow it down.

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[mseitz24]

MM3 support said it’s likely a short somewhere.

They said i could try a new obd cable for $15, or they’d sell me a new control box for $500.

I started reconnecting all the components one by one, and I can get everything hooked up without the light issue except for the 2 wire cable that goes to the engine bay.

As soon as that’s plugged in, the TPMS light will come on.

The thing is, I still get no power to the screen, so I’m thinking it’s the box, not just that cable.

I’m still waiting for a reply from them on what I found.

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[AK Bob]

MM3 support said it’s likely a short somewhere.

They said i could try a new obd cable for $15, or they’d sell me a new control box for $500.

I started reconnecting all the components one by one, and I can get everything hooked up without the light issue except for the 2 wire cable that goes to the engine bay.

As soon as that’s plugged in, the TPMS light will come on.

The thing is, I still get no power to the screen, so I’m thinking it’s the box, not just that cable.

I’m still waiting for a reply from them on what I found.

I agree that the MM3 should power up and display without the OTF cable being hooked up.

Thinking it could still be a bad OBD cable or port.

Have you tried hooking up a scan tool to see if the OBD port works okay?

Please keep us posted on what MM3 Power support has to say and your progress.

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[mseitz24]

No, I haven't.

Support mentioned that the truck OBD port could be possible, but I figured everything seemed to be ok without the MM3 plugged in, so the problem was with the unit itself.

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