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ecu/pcm swap - vin issue?

F

fordtech

NAXJA Forum User
Location
Amherst NY
Can anyone verify if there is an issue with the VIN not matching when swapping ecu/pcm (used, not a reman) in a 98?? I have read varrying information on the subject.
If there is, can it be re-flashed by the dealer to input the correct VIN?

Here in NY, as many states are, you can't pass inspection with a check engine light.

Thanks
 
you could just find someone with an OBDII scanner and have them get rid of the code(s) for you.I believe they will stay off for 19 days?
 
andyanderson said:
you could just find someone with an OBDII scanner and have them get rid of the code(s) for you.I believe they will stay off for 19 days?
Click to expand...

That didn't work for me. Their smog machine was able to tell that the codes were recently reset. He told me to drive around for 100 miles and then come back. I did and the smog machine still failed it based on that.
 
I swapped the ecm in my 2K without a light or problem. New one went in and my light went away. My mileage on the odometer did not change either. HTH
 
natep1 said:
I swapped the ecm in my 2K without a light or problem. New one went in and my light went away. My mileage on the odometer did not change either. HTH
Click to expand...

That was a new one though right? I'm talking used..... I will call the dealer today and see what they say.
 
Heres the deal in New york. I had to put a new PCM in my jeep also. I asked my buddy what will happen when I come in for inspection next time. The Vin does not have to match vehicle as long as the vehicle that PCM is from has gone to the great scrapyard in sky. Not having the correct Vin will put up a Red Flag with inspection board. They will check and confirm that the Vin from new PCM has not been recently inspected(trying to cheat check engine light by swapping PCM's)and vehcile is no longer on road. Meaning as long as donor vehicle has been scrapped there is no problem. Sure you could waste your money to have a computer reflashed, but for the same cost you can pick up a spare PCM(insurance).

Exhaust Gas analizers cant tell if a check engine light is on, they only check for the presence of Hydocarbons and other crap in exhaust and coolant. They will point you to internal engine problems like a bad head gasket leaking coolant into combustion chamber.

The dealer will obviously tell you to come in and spend money at their shop!! Ever hear of the Wallet VAC!!!!
 
Last edited:
theoriginalscion said:
Heres the deal in New york. I had to put a new PCM in my jeep also. I asked my buddy what will happen when I come in for inspection next time. The Vin does not have to match vehicle as long as the vehicle that PCM is from has gone to the great scrapyard in sky. Not having the correct Vin will put up a Red Flag with inspection board. They will check and confirm that the Vin from new PCM has not been recently inspected(trying to cheat check engine light by swapping PCM's)and vehcile is no longer on road. Meaning as long as donor vehicle has been scrapped there is no problem. Sure you could waste your money to have a computer reflashed, but for the same cost you can pick up a spare PCM(insurance).

Exhaust Gas analizers cant tell if a check engine light is on, they only check for the presence of Hydocarbons and other crap in exhaust and coolant. They will point you to internal engine problems like a bad head gasket leaking coolant into combustion chamber.

The dealer will obviously tell you to come in and spend money at their shop!! Ever hear of the Wallet VAC!!!!
Click to expand...


This is excellent news. The Jeep the pcm is from is long gone, I am sure of it.

I e-mailed the State about the situation to get the official response.

So, when you did this, did they pass it, or did you have to wait until they verified the VIN was not in use on another Jeep? Does your check engine light stay on as a result of the code?

Thanks!
 
I'm not up for inspection yet, computer died not a month after my last inspection. I asked my buddy down at the Shop the same question last week. I don't wat to pay a hour labor to have VIN flashed. I got a couple more months.

I don't have any codes(presently), if you have any get them read and start figureing out whats wrong. The MIL light needs to be off, and driven through 40 drive cycles or somthing.

If you just need a replacment PCM cause original is bad, put a new one in and see what happens.

Please tell what the State says.
 
fordtech said:
That was a new one though right? I'm talking used..... I will call the dealer today and see what they say.
Click to expand...
Used. $50 from the local boneyard.
 
I was worried about the light being on, sounds like it won't come on. I have some time before inspection to figure it all out/get a reflash if needed.

I was looking through the FSMs I have and that code is not listed in 97,99, 2000, so maybe they won't throw the code??

My plan at this point is to swap the PCM, drive it, and found out from NYS about the mismatch.
 
Some FYI, VIN numbers are burnt into the PCMs memory and can't be changed....no matter what.
A flash is just a software update, you will notice your PCM part number ends in a AA or AB or AC and so on, these are showing a revision to the software in the PCM, they do not and can not change the VIN number.
 
waxer said:
That didn't work for me. Their smog machine was able to tell that the codes were recently reset. He told me to drive around for 100 miles and then come back. I did and the smog machine still failed it based on that.
Click to expand...
that was because you hadn't ran all of the on board tests for the evap system. drive it a few more times and it should kick over automatically and be good as long as everything is ok. some scanners like mine will allow you to reset the codes and re-run the tests on the spot which is what I do to verify if theres a actual problem in stead of waiting till the light comes back on
 
JEFF said:
Some FYI, VIN numbers are burnt into the PCMs memory and can't be changed....no matter what.
A flash is just a software update, you will notice your PCM part number ends in a AA or AB or AC and so on, these are showing a revision to the software in the PCM, they do not and can not change the VIN number.
Click to expand...

The dealer I spoke to did seem to think they could do it. All I asked was 'if I use a used pcm would there be any issues', he specifically told me they would need to change the vin in the pcm.

I know what a flash is, and how it works. What I don't know is how you would go about changing the vin. I don't ever remember running into the vin issue on Fords....

NYS DMV sent me a number to call to discuss. I'll see how that goes.

Thanks to everyone for the information.
 
If they can change the VIN your lucky, I've tried to do the before several times with no luck.
 
JEFF said:
If they can change the VIN your lucky, I've tried to do the before several times with no luck.
Click to expand...

This is definitally the information I have gotten from most internet sources (posts, sites, etc).

I found out the part # at least- 56041 531AB 1 ER0 DBB w/Federal Emissions
 
The issue is that on OBDII vehicles, the testing stations do not manually enter the vin. They simply plug the testing computer in, which then gets the vin from the ECM and checks the emissions readiness as determined by the ECM. Some states are not even sniffing the exhaust for OBDII vehicles. Depending on the testing system, it might just show the vin number for confirmation and not give the operator a chance to change the vin before the results are sent by modem back the DMV. This is probably deliberate to keep the testing centers honest and not let them cheat by putting in a vin number for a different vehicle.
 
To the best of my knowledge the 97-01 XJ PCMs DO NOT have vin information entered in them. ECUs being coded with the vin information was not required untill later models years.

Additionally I cannot recall any mention of retrieving the vin in the FSM via the DRBIII.
 
I did a bit more homework on this. The OBDII spec defines how the vin info is stored and retrieved, but it didn't require that the vin info be readable. Apparently for 2008 and newer it is required to have the vin info to address the problem of cheating. The 2008 changes also mandate that all US cars use the CAN signalling, instead of the handful of different "flavors" currently in use.
 
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