LC2 harness to non BRF 2004r wiring/3rd gear TCC lockup


What's Fuel Injection?
Mar 9, 2009
I have an LC2 setup I am swapping into a 80 century wagon. I bought a pile of GN parts (intake, harness, manifolds ect) minus a long block a and bolted all the GN stuff on a fresh 4.1 I put together. I have a CRF code 2004r I have laying around from my 305 SBC 86 grand prix 2+2 that I bolted behind this 4.1.

The CRF code 2004r I have has the harness diagram similar to the KCF in this diagram. I have 1 wire coming from the plug on the trans going to the lockup pressure sensor and 2 wires going to the TCC solenoid. Pin A and C are for the TCC, pin B is for the 4th gear lockup switch.

The BRF uses 3rd AND 4th gear pressure sensors for lockup, my LC2 harness has provisions for this but the plug won't go into my CRF code 2004r.

What do I need to do wiring harness wise to put this non BRF 3 wire, 4th gear only lockup 2004r behind the LC2 4 wire 3rd and 4th gear lockup harness? Can I just "re key" (grind the slot in the plug) the plug so it will go into the transmission and not use the 3rd gear lockup? The dark green/white connector is pin C7 on ECM.

If I just leave the 3rd gear lockup wire disconnected, will the ECM throw a code? Will 4th gear lockup function as normal?