05 Acura TSX (lost communication TAC module) U0107

I've followed the service manual steps for this DTC, which mostly has you checking voltages & continuity at and between the PCM, TAC module & TAC module relay. EVERY step shows normal values except one that has you probing the TAC module +B terminal and grounding other meter lead. It says to turn ignition on and asks if there is battery voltage for about 2 seconds...mine shows battery voltage but it will continue to have that voltage as long as the key is on?! The other thing that isn't right is one of the first steps has you looking into the throttle body to check the plate..it says to hold accelerator on WOT, turn on ignition and then asks if the throttle opens again after closing. Mine will only open once and quickly closes back. This limp mode issue has been constant since it popped up. I've tried clearing code & have replaced the TAC module but it won't go away!
There's one other issue that's intermittent..sometimes I have to push in the override right beside the gear selector to get the car to go into reverse..when this happens it feels almost like the brake pedal won't go down quite as far..there's no DTC for this and there's no pattern to when it'll work & not work.
This car has K Line protocol so no CAN bus. The PCM is corroded on the drivers side which is the opposite side as where the connectors are. I've tried removing it to see if there's corrosion on the PCB but I can't get the bolts to budge!! There was a recall on PCM for corrosion but I won't even get into that!!
Im trying to figure out if there's anything else I can test to MAKE SURE the pcm is the culprit. What shld the resistance be on ground pins, serial line...any of the circuits..the continuity was good but im curious whether their resistances are normal.
Thx!

hey there, I saw there is around 50 some checks for this fault code, looked over them, and the wiring diagram.

that ecm is a helluva thing with the corrosion. how is the connector and pins???

what kinda of ground reading are you getting at pin 7 at the tac??

also, did you check the relay socket, and make sure the pins and wires are good??

do you have good power at pin 2 with key on?? and if you jump the relay what kind of voltage are you getting??

if i had to guess though. possibly faulty tac is faulty

I would address the corrosion on the PCM before continuing diagnosis, that looks pretty bad. On thing that's common on those is a plugged HVAC evaporator drain. Or some rookie oil changers like to fold it over so it doesn't drip on them during service and forget to return it. The water builds up and the HVAC box drips it directly on the PCM. So if you decide to replace the PCM, you'll want to make sure that drain flows properly.

The shift interlock issue you're talking about could be an intermittent brake switch fault. When it happens, make sure you have brake lights. The interlock won't release if it doesn't get proper brake switch input.