2017 2500 6.4 frying PCM's

[FixxerAuto]

So i recently had this truck come in no crank no start. The previous owner replaced the PCM and now the replacment was also bad. I checked all grounds and load tested every power and ground to the PCM- no issues at all. I put a used PCM in and the truck fired right up and ran fine. Voltage was good- no codes besides the misconfiguration codes due to a used PCM. I also replaced the alternator just in case it may have been overcharging. After running the truck for a couple days and not finding anything I send it back to the customer- he gets about 3 miles away and the PCM fried again. They took it to the dealer who put a new PCM in it and it also fried- they couldn't figure out why. Any ideas? I was thinking replace everything on the engine and inside the transmission wiring and all. It costs around $200 for a PCM each time you try something to find the issue.​

 

[04fxdwgi]

Sounds like the +12V is crossing over to a 5V signal circuits or directly to ground somewhere. Look for damaged wiring or bad corrosion / damage in a wiring connector. Also, check all your grounds to ensure they are clean and tight. Something may be backfeeding somewhere do to a crappy ground.

 

[Burla]

Is that wired through a TIPM? If it isn't in the wire, it has to come from a short somewhere.

 

[FixxerAuto]

Is that wired through a TIPM? If it isn't in the wire, it has to come from a short somewhere.

It doesn't seem to be powered by a TIPM. The short "somewhere" is my problem as every time it happens the ECM is completely gone. Need to figure out a plan to fix this thing that doesn't invlovle a stack of dead $200 PCMs to find the problem...

 

[FixxerAuto]

Sounds like the +12V is crossing over to a 5V signal circuits or directly to ground somewhere. Look for damaged wiring or bad corrosion / damage in a wiring connector. Also, check all your grounds to ensure they are clean and tight. Something may be backfeeding somewhere do to a crappy ground.

Yeah, i load tested and cleaned the grounds with no results. The next step would be to take the wiring harness and strip it all the way down or replace it i suppose- but it could still be a component or sensor as well and it is intermittent/ When it happens the truck dies and wont restart unless you put in another PCM. There is no communication or anything

 

[Ken226]

It doesn't seem to be powered by a TIPM. The short "somewhere" is my problem as every time it happens the ECM is completely gone. Need to figure out a plan to fix this thing that doesn't invlovle a stack of dead $200 PCMs to find the problem...

Are you sure? Because according to the factory wiring diagram from my 2013 1500, the power comes into the PCM from the TIPM on two different paths. Main power through the 20a fuse#22, and switched power through the Run/Start relay and the 10a fuse 78.







Have you looked at a wiring diagram specific to the truck year/make/model that you are working on to verify where the PCM gets its power from?

 

[Burla]

It doesn't seem to be powered by a TIPM. The short "somewhere" is my problem as every time it happens the ECM is completely gone. Need to figure out a plan to fix this thing that doesn't invlovle a stack of dead $200 PCMs to find the problem...

So going off what Ken said, the issues with TIPM's are solder joints under the relay, that when they corrode from current going through or natural age, it creates a short. Kinda crazy the item meant to prervent shorts creates a short, but its a fact and can explain why it is possible your item keeps getting fried over and over. Not sure on work arounds but that would include bypass TIPM of type or fixing solder joints in TIPM>

 

[Burla]

Hemi395 finds all these cool fix videos out there..

Now the question is because your item is past the relay, it is still possible to have a short from it. I don't know the answer to that question, if it is yes, this could explain what's going on.

Chrysler / Dodge : TIPM Repair - No Wipers

In this video I help my sister out by repairing her TIPM (totally integrated power module) on her 2014 Dodge Grand Caravan 3.6L. The customer complaint was, ...

youtu.be

Answer..

Yes, a faulty Totally Integrated Power Module (TIPM) can potentially damage or "fry" the Powertrain Control Module (PCM), though it's not a common occurrence. While TIPMs are designed to protect the electrical system, a severe failure can cause cascading issues that affect the PCM.
How a faulty TIPM can damage a PCM
The TIPM acts as the central hub for a vehicle's electrical system, distributing power and managing communication between various components, including the PCM. Most of the time, the TIPM's integrated fuses and relays protect other modules from electrical damage. However, a major internal failure can lead to more serious consequences.

• Voltage spikes: Electrical overloads or shorts within the TIPM, possibly caused by moisture or component defects, can cause uncontrolled voltage spikes. If these spikes are not contained within the TIPM, they can travel down the communication bus or a shared power circuit and overwhelm the sensitive microprocessors in the PCM.
• Failed communication: A severely corrupted or failed TIPM can cause communication errors with the PCM, sometimes triggering a specific diagnostic trouble code like U0100 ("Lost Communication with ECM/PCM"). While a communication error doesn't automatically mean the PCM is "fried," a persistent and severe communication breakdown can cause other modules to malfunction or operate erratically.

• Internal shorts: Internal shorts within the TIPM, especially if related to a circuit that directly supplies power to the PCM, can create a continuous or uncontrolled electrical load. A short could cause a fuse to blow, but a major internal hardware failure in the TIPM could bypass these safeguards, causing a permanent overload that damages the PCM.

The opposite is more likely
It is important to note that damage to the PCM from a faulty TIPM is rare. Electrical systems are designed to protect against this kind of catastrophic failure. It is more common for a failing TIPM to mimic the symptoms of a bad PCM, leading to misdiagnosis.
If your vehicle is exhibiting the following symptoms, a faulty TIPM is a more likely culprit than a "fried" PCM:

• Erratic electrical issues (flickering headlights, random horn honking).
• The engine cranks but won't start.

.

 

[Dtrain]

So i recently had this truck come in no crank no start. The previous owner replaced the PCM and now the replacment was also bad. I checked all grounds and load tested every power and ground to the PCM- no issues at all. I put a used PCM in and the truck fired right up and ran fine. Voltage was good- no codes besides the misconfiguration codes due to a used PCM. I also replaced the alternator just in case it may have been overcharging. After running the truck for a couple days and not finding anything I send it back to the customer- he gets about 3 miles away and the PCM fried again. They took it to the dealer who put a new PCM in it and it also fried- they couldn't figure out why. Any ideas? I was thinking replace everything on the engine and inside the transmission wiring and all. It costs around $200 for a PCM each time you try something to find the issue.​

Did you ever figure out the issue? I’m having the same issue and no shop can figure it out.

 

[Ken226]

Did you ever figure out the issue? I’m having the same issue and no shop can figure it out.

That guy posted his question, then checked in the next day for answers. Last seen the day after he posted. I'd be shocked if we ever hear from him again.




What, specifically, is the issue with the PCM. The previous post, he said "fried" the PCM, but never specified exactly what this means. There are many hundreds of ways a PCM can be "fried". His PCM might have been deep fried, where yours is only pan fried, stir fried, air fried or something else entirely.

What is it that the PCM is failing to do, because them mode of failure is a clue as to what is causing the failure.


An example:
If a bunch of sensors aren't working. You replaced them with know good sensors and they still don't work. The circuits check out. You check the PCM 5v reference and there is no signal. So, your replace the PCM and it runs, all is well with the world. Then three days later, the PCM has lost its 5v output again. Replace the PCM again, and a few days later, the 3rd PCM loses its 5v output. In this situation, you can kinda guess that what 04fxdwg mentioned up above, is happenning. A 12v circuit is shorting to a 5v wire and burning out the 5v output inside the PCM.

"Fried PCM" isn't nearly specific enough to diagnose anything.

 

[04fxdwgi]

There is a strong possibility (although not that common) of something like the TIPM is shorting the +12 VDC and injecting it into the 5 VDC signal to / from ECM or BCM and boning the entire system.