MM3 Tuner - ECM Communication Error - Code 18504

[Morbious]

I have the manual downloaded!

Can someone point me in the right direction to check the connection to ECM from the OBD2 port?

I'm getting error code 18504 from the MM3 tuner.

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[AK Bob]

I have the manual downloaded!

Can someone point me in the right direction to check the connection to ECM from the OBD2 port?

I'm getting error code 18504 from the MM3 tuner.

First, verify that your OBD port is operating correctly.

This can be accomplished by connecting a scan tool to see if you can communicate with the ECM.

Next, check the OTF cable connecting the J1939 port in the engine bay to the MM3 communications module under the dash.

Check this cable is plugged in correctly on both ends and look for any signs of physical damage.

Disconnect the cable and check each wire with an ohm meter for open, ground, and shorts.

If everything checks good but the issue persists it may be the MM3 communications module, contact MM3 Power for technical support.

http://mm3power.com/contact/

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[Morbious]

I tried connecting the scanner, and it won't read!

Did the MM3 tuner brick my computer?

Also, I believe it currently doesn't have a tune loaded onto it!

Failed to load tune, then failed to reload stock, so does that mean the computer is blank right now?

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[watersupply189]

I tried connecting the scanner, and it won't read!

Did the MM3 tuner brick my computer?

Also, I believe it currently doesn't have a tune loaded onto it!

Failed to load tune, then failed to reload stock, so does that mean the computer is blank right now?

If your truck will start, then it’s not bricked.

Did you have a battery charger connected when trying to download it?

Batteries need to be at or above 12.6 volts.

Also, check behind the OBD port to make sure the harness wasn’t disconnected by accident.


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

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[Morbious]

I haven't tried starting it without a tune loaded onto it!

I didn't have a charger connected to the first few tries but did make sure both batteries were fresh off the charger; I am currently trying with the charger connected.

Wires going into the back of the OBD2 port seem snug.

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[AK Bob]

I tried connecting the scanner, and it won't read!

Did the MM3 tuner brick my computer?

Also, I believe it currently doesn't have a tune loaded onto it!

Failed to load tune, then failed to reload stock, so does that mean the computer is blank right now?

What scanner are you using?

You need to use a scan tool that can communicate with all the modules.

If the scan tool doesn’t communicate any modules, then you have an issue with the OBD port or CAN Bus network.

If some of the modules are communicating but the PCM is not, you may have a bricked PCM.

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[Morbious]

Innova 1000 carscan mobile.

How do I check OBD2 port and can bis?

I know the port is receiving power!

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[AK Bob]

Innova 1000 carscan mobile.

How do I check OBD2 port and can bis?

I know the port is receiving power!

Okay, I looked up the Innova 1000 scanner, and I don’t think it will be very helpful with troubleshooting your OBD port.

I am looking at the OBD diagram from your previous thread (attached below).

You should have power (positive battery voltage) on pin 16 and grounds on pins 4 & 5 (negative battery voltage).

So check with a meter for power between pin #16 and both #4 & #5 for battery voltage.

CAN high is on #6 and CAN low is on #14 .

The best way to check the CAN signal is with an oscilloscope.

But you should see approximately 0.5V DC between pin #6 and pin #14 and 2.75V DC between pin #14 & ground and 2.2V DC between pin #6 and ground.

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[Morbious]

Is that testing done with a key on/off, or doesn't matter?

Are those measurements with a multimeter correct?

Thanks so much, you have been a major help!!!

My ECM erased itself, and nobody could tell me why.

I'm now wondering if it had something to do with TIPM going bad!

I replaced ECM but am unable to load a tune.

It loaded the first time I tried them, but the trans-tune wouldn't load.

I read somewhere that reloading the ECM tune worked, but when I tried that, it failed to write, and I've been stuck trying to reload the stock file minus one success.

Then, it failed to write a new tune, and I am now stuck trying to reload the stock file again.

Now, I can't communicate with ECM.

Probably a bricked ECM?

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[AK Bob]

Is that testing done with a key on/off, or doesn't matter?

Are those measurements with a multimeter correct?

Thanks so much, you have been a major help!!!

My ECM erased itself, and nobody could tell me why.

I'm now wondering if it had something to do with TIPM going bad!

I replaced ECM but am unable to load a tune.

It loaded the first time I tried them, but the trans-tune wouldn't load.

I read somewhere that reloading the ECM tune worked, but when I tried that, it failed to write, and I've been stuck trying to reload the stock file minus one success.

Then, it failed to write a new tune, and I am now stuck trying to reload the stock file again.

Now, I can't communicate with ECM.

Probably a bricked ECM?

All measurements so far have been taken with a multimeter on volts DC.

When measuring the power and grounds, the key position doesn’t matter.

However, when measuring the CAN bus voltage, the key must be in the run position.

Unfortunately, I am not familiar with the CAN Bus topology layout on the 3rd Gens.

Looking at the limited information in the manual, it appears that the TIPM is the gateway, and you should be able to communicate with it directly from the OBD port.

The voltage checks on pins#6 &#14 with the key in the run position will at least verify that the OBD is connected and communicating with the TIPM.

It appears that the TIPM is the hub for the CAN bus and transmits to the ECM and other modules.

You may be unable to communicate with the ECM because of a failure in the TIPM.

https://tipmrebuilders.com/chrysler-...-tipm-failure/

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