User-c3

have a 99 f-body LS1 with t-56. Will a ECM from an 04 GTO T-56 work with my motor?

psiconversion

iTrader: (5)

If you are going to use the fbody harness, you will have to change the pcm retainer from red to green, add s few grounds and pwm the o2 heaters. If you need a pinout let me know.

Jon
PSI

User-c3

good to know thanks, more work than I think is needed to justify getting it.

69 Ghost

It will plug and play with a GTO OS. You do not have to repin anything if you do not want to but you will get some codes for the O2 heaters due to the diagnostics but you have to turn them off. I believe the gas gauge is reversed also and you will have to set the VATS for the BCM if memory serves me right. The rest should be good including the A/C, etc. For what it is worth the 04 GTO PCM has about 3x faster processor. I believe the 411 is about 16mhz and the 243 is about 40mhz. It also has twice the flash memory.