Besides disconnecting the batteries, disconnecting the firewall wire harness, and unbolting the cradle under the dash... what else must be done to swap pcms?

Does the VIN have to be programmed into the new PCM with a scan tool?

What if the right calibration is already on the PCM I want to switch to?



Suppose my truck currently has PMT1, and I bought a PCM that has PMT2 already loaded into it by Ford. If I unplug my current PMT1 PCM, and plug in the PMT2 PCM, is there anything else that must be done for the truck to work properly?

 

Plug and play. I've never disconnected the batts. Just unplug under the hood and swap it out. KEYS OUT OF THE IGNITION.
Why may I ask are you swapping PCM's?

 

I'm swapping PCMs because I want to see how an updated calibration feels. I've read about people updating their PCMs for years, while I've just lumbered along not even knowing how a different calibration, especially an updated one, might improve the powertrain characteristics.

I also want to test why my new scan tool can't identify my current PCM. If the scan tool can identify the new PCM I install, then the issue is likely with my old PCM. If the scan tool can't identify my new PCM either, then that makes two PCMs that my scan tool can't identify, which indicates a problem with the new scan tool.

I just wanted to make sure I don't need to do anything with fuse #30, or have to program a VIN in, or anything else that I don't even know to ask. So I'm checking with you guys first.

 

what scan tool are you using? if you are using autoengunity be sure the key code is in your computer. if you switched laptops and didn't enter the right code it will not recognize the pcm

 

I swapped mine out for a newer one as well. More so for tuning.
Is your scan tool getting power from the obd2 port? or is it just not connecting?

 

I'm using the Ford / Hickok New Generation Star Tester with the most up to date software.

Whatever it was that you said about AE sounded too complicated for me, which is the reason why I paid a bit more for the dedicated NGS. I don't have to do anything but plug the NGS in and it works, any Ford, any time.

MY new NGS read the PCM of my gas engine Fords just fine, but it didn't read my diesel PCM, but I have a suspicion why. By swapping PCM's with one I bought directly from Ford, I can confirm it.

 

Sorry, we cross posted Frank...

The NGS has no trouble pulling codes and monitoring PIDs of my old PCM, it just cannot identify it under the Module ID screen. So while the NGS can identify, by part number and revision code, all of the other modules in my truck, such as the GEM, the CTM, the ABS, etc, it produces hash when it comes to identifying the part number and software revision of the old PCM.

I know what the part number and software of my old PCM is. But I don't know why my (brand new, not used) NGS can't identify it, even while it has no trouble reading DTCs and PIDs from it.

Hence, I want to swap in a new PCM to see if the NGS will identify it as easily as it identified the PCM's to both of my gas engine Fords.

I hope that makes more sense now.

And yes, the scan tool is getting power through the OBDII DLC no problem.

 

I am not sure what you mean by "read the PCM" but if you are referring to pulling the VIN so it can identify the year, make and model then that feature doesn't work on the 7.3 liter trucks (at least not with the scanners that I have tried....). It works on the 6.0 and newer and of course all gas engines.

If your truck is an automatic, then you want to make sure you replace it with another PCM code that is also for automatic transmissions. Judging by your avatar, it looks like you are talking about an F550 truck. If so, then you want a PCM code for chassis cab vs pickup if you are wanting to compare the two. The transmission control between the two versions is very different.

EDIT: To answer your last question.....you do not need to reprogram the new PCM with your VIN. That doesn't matter on these trucks.

 

Shake-n-Bake ... yes, the replacement PCM is for a cab chassis automatic.

As for reading the PCM, I'm not trying to pull the VIN... I'm trying to pull the part number for the PCM.

I'll post a couple of pics of what I'm getting, versus what I'm looking for.

 

OK, here is what I'm talking about. The first pic is of my current (aka old, aka original) diesel PCM. The Module Id is hash. This does NOT happen with the same PCM Module ID query, when the NGS is plugged into my V10 Triton engine.

The exact part number I'm expecting to show in one of the lines on the screen below is XC3F-12A650-PF. Instead, I get this:



However, in the same diesel truck, the other Module identities report fine...

ABS Module example:



Central Timer Module example:




So, my expectation is that the PCM should report the same way... not jibberish. On my V10, the NGS could not identify which ABS module I had, which is interesting, because in that year, Ford changed the ABS module. The NGS reported ????-??????-?? (a bunch of question marks, literally). But even THAT is more confidence inspiring, and less concerning, than the random hash of the diesel PCM, shown above.

 

I see what you are saying.
If I try and pull a VIN query with AE with the engine running it will kill the engine...so I stopped doing that. I think there is something different with the 7.3 PCMs that don't allow that function. Go ahead and try the new PCM and see if it reports any differently. I'd be curious to see what happens.

BTW, if you have a PTO trans, then your high idle circuit won't work after you swap PCMs. You will have to drive the truck around the block and get it up to a reasonable speed (30 mph or so...) and then you can pull over and try again and it should work fine afterwards.

 

I disconnected the batteries, put the new PCM in, reconnected the batteries, and it won't start.

The IDM is not communicating with the new PCM. (EF not detected). Cranks sound horrible.

Your thoughts?

I plan to pull the new PCM and look at the pin field to see if any pins got bent.
At that point I'll put back in my old (known good) PCM and see it talks with the IDM, in order rule out the IDM and the harness in between.

But after all that, I still want to try the new PCM.

Is there a secret step to swapping PCM's that I missed, which caused the lack of communication with the IDM?

 

Forgot to mention that the new PCM reads inverse video hash on the Module ID also.

The specific data that is blanked out is

- Module Part #
- Software Level
- Version Date

Any thoughts?

I ran a buzz test with the new PCM. I didn't think it would work because the new PCM and the IDM aren't talking. And, sure enough, it didn't work.

Self Demand KOEO had communication error with IDM also. So basically codes 1670 and 1668 will appear all day long, with no start, with this PCM installed such as I did.

Anyone else ever read about, hear about, or have a bad dream about this scenario?

 

I tested a third 7.3L PCM (in a different truck, a 2002 model), and the same hash appears.

Shake-n-Bake, you might be on to something. Three 7.3L PCM read do not report their part number and software revision. However, this was all with one NGS tester. To know for certain, one would need to check the same PCMs with another NGS tester.

I've ordered a second NGS, in order to compare. If two NGS testers and cards can't read 7.3L PCM software revision ID's, then we will know for certain that the 2000 and 2002 Module Part #s and software level are not specifically identifiable by part number to the Ford factory scan tool. Presumably, this would apply to all 99-03 7.3L diesels.

If the second NGS does report the info, then I'll know that the first NGS needs to be returned as defective. (I can only return if it is defective.) If both scanners report the same thing, then there is nothing wrong with my first one, and I'll have an extra NGS available that I won't need, complete with the latest and last versions of red, green and black service and diagnostics cards that cover all Fords from 1984-2004.

Still bumping for ideas on the IDM communication issue with the new PCM.

 

Are you mixing generations? I would not expect a '02-'03 PCM to work on a '99-'01 truck and vice versa. The PCM pin out is different between the two versions.

Maybe Cody will see this thread and confirm if the PCMs are interchangeable between those years.