I have a 94 bronco 5.0 e40d I recently had to change my ecm due to three burnt spots in it the original was F4TF-12A650-AAA and my replacement was AAB from autozone now I'm getting a crank no start and alot of transmission codes they are 637,654,621,622,626,and 629 I know what the codes are and my connections and wires seem to be ok I'm not sure what else to look for

 

I'm new to this forum and i'm hoping your post looking for ECM help is current.....My suggestion would be to visit an LKQ Pick Your Part yard and look for similar year/code used ECM. The guys at the front gate might even let you borrow the used ECU for an hour to test it in the parking lot on your truck? Theres a "value" test between pins on the module that can help tell if used module is working.Good luck.

 

some 94 broncos came with speed density efi, while others had MAF. I would agree that getting an ecu from a yard might be a better solution.

 

That would be a great idea but I'm in South Mississippi and the nearest one I found in a salvage yard was in South Georgia and almost wanted just as much a a new one so testing is not an option however I did find one a remanufactured one with AutoZone and hooked it up and got the transmission codes so I switched the relays between the pcm and the horn and still getting codes so AutoZone has me another one coming in the morning to try and if it doesn't work they will reimburse me but still leaves me in the same boat and if that happens I'll will purchase a new one

 

There are no new computers available anymore. Not sure why they substituted the -AAB for the -AAA version. They are both available under different Cardone Part Numbers. As much as I dislike Cardone they are pretty much the only game in town anymore. I would press da'Zone counter jockeys for the correct -AAA version.

I do not know for sure what the differences are between those computers. Both are listed for a F-series with a 5L engine and E4OD transmission. No mention whether either or both are Speed Density computers or MAF.

Edit:it looks like F4TF-12A650-AAA is Code HOG0 which is a MAF computer for 5L F150/Bronco & E4OD transmission. F4TF-AAB is a HOG1, also listed for a 5L F15o/Bronco & E4OD trans. MAF


So your issue with the replacement is most likely it's bad right out of the box. Common problem with Cardone.

 

https://www.fs1inc.com/catalogsearch...94+FORD+BRONCO Site I stumbled upon when looking at the capacitors in my computer Few yrs back Good luck TR