Does anyone have a proper circuit schematic for a Ford BA series PCM?

Tiny
VALLEYKING
  • MEMBER
  • 2003 FORD FAIRMONT
  • 4.0L
  • 6 CYL
  • 80,000 MILES
This model has a common problem with old PCMs developing cracks on the circuit board, meaning they won't start when cold. Replacement parts are no longer manufactured nor is there a compatible generic solution. In order to find the location of the error to effect repairs, I am looking for a circuit schematic of the PCM (note not a pinout/wiring diagram which are readily available and of no help).
Saturday, June 14th, 2025 AT 10:22 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,404 POSTS
Yep, bummer, sorry only the manufacturers would have that diagram that I know of. Can you get a used unit? They are plug and play.
Was this
answer
helpful?
Yes
No
-1
Sunday, June 15th, 2025 AT 11:25 AM
Tiny
VALLEYKING
  • MEMBER
  • 2 POSTS
They aren't plug and play. They are coded to match the vehicle computer and console. Any mismatch between the 3 and that part of the car won't work, so it needs to be specially recoded turning a $60 repair into a $1,000+ repair because of the specialist equipment required.
Was this
answer
helpful?
Yes
No
Sunday, June 15th, 2025 AT 9:11 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,404 POSTS
And there you go; I have swapped out the engine computer before and they worked for the crown vic's but maybe it is different for the Fairmount.
Was this
answer
helpful?
Yes
No
Monday, June 16th, 2025 AT 10:11 AM

Please login or register to post a reply.