F47F 12A650 CPA vs CRA

[Tulsa Time]

I have a 1993 Ranger, 4x4, automatic. When the 3.0 lost a couple of cylinders, I replaced it with a 4.0, A4LD out of a 1994, 2wd. I changed the tail shaft in the 2wd transmission to maintain the 4x4 capability but I used the 2wd ECM (F47F 12A650 CPA). From a swap perspective, I have had no trouble in the seven years since.
I have, however, since developed a problem and have pinpointed the cause to be a failed ECM.
Both F47F 12A650 CPA and F47F 12A650 CRA show to work for 1994, 4.0, automatic, with federal emissions. The CPA shows to be for a 2wd and the CRA a 4x4.
-Does anyone know the difference between the two? (Software? Hardware?)
-Since the CRA is less than half the price, can I replace my CPA with a CRA?
-Would I be better off using a CRA?
-Did all 4.0 automatics with federal emissions come with no EGR in 1994?
Thanks for reading.
Craig

 

[rusty ol ranger]

I am going to *guess* the difference is either electronic vs manually engaged transfer case...but i really dont know for sure.

 

[Tulsa Time]

It has an electrically engaged transfer case, but it is operated by the electric shift control module so it functions as designed.

 

[RonD]

The Federal 4.0l OHV didn't get EGR(and Cam sensor) until 1995 and up
Only Calif had it 1990-1994

There is no connection between 4WD system and computer(PCM) in any year Ranger, so that shouldn't be an issue


In 2001 and up the PCM sent the Speed Signal to 4WD system but thats the only connection and its just for shifting to 4Low

So get the 2WD PCM at half the price, it will work fine

 

[Tulsa Time]

Thank you, RonD. That is what I was hoping to hear.