Thefireball

A little bit of background about the on going situation now:
My first thread was about my 4th gear not working, and was fixed when the ecu was reset. Now it will not engage at all, and I have a Check engine light that does not turn off, and the code came back as P1607 - PCM Internal circuit failure. I just got a new (used) PCM off of eBay that matches the part number exactly.
Now obviously, I need to get my keys programmed to it for the car to start. I'm aware talking about immobilizers is an iffy topic due to thieves, however, what I need to know is if I can skip paying $180 to have that done by the dealership by simply desoldering the Immobilizer off of the PCM/ECU itself, and soldering it onto the new one?
I don't see why this wouldn't work considering you can start the car if you remove it, granted, you'll have a CEL.

And yes, I know how to do soldering work. I'm not worried about damaging any of the components.

justnspace

iTrader: (1)

if you arent scared of damaging unit and have the skill, why not do it?
if it doesnt work, you're out a PCM.

Because EVERY response here,will tell you to go to the dealer.

Thefireball

You're right about everyone telling me to go to the dealer. I just don't want to waste my time attempting it only to find out it doesn't work. I've already scheduled to have the dealership do it Tuesday, but I'd prefer to use that $180 towards something more worthwhile.

justnspace

iTrader: (1)

you dont think getting your car to start is worthwhile?

Thefireball

It starts and drives just fine. It's my 4th gear that doesn't work.

justnspace

iTrader: (1)

??????
a broken immobilizer prevents the car from starting and driving...
it's what pairs the KEY to the Computer.

if your car starts and drives...why do you need to replace the immobilizer?

Thefireball

I stated why in the OP.
4th gear would randomly stopped working and the CEL would come on, and I would reset the ECU by pulling the fuse, and my 4th gear would magically work again for 2 weeks, then repeat.
Now it doesn't work, and I have a permanent CEL on, which I scanned the code for, and it came back with 'Error P1607: PCM Internal Circuit Failure'. I can either swap out the PCM, or have mine sent off to be repaired.
But you can't just swap out PCMs and expect it to work. You need to have your keys programmed to it or else the car doesn't start. I should know, I tried just to see what would happen, and the car instantly turns off when you attempt to crank it.

justnspace

iTrader: (1)

you dont have much of a choice here...
You CAN try doing your backyard mechanics route, or you ship the PCM to get repaired...

lol and around and around we go.

Thefireball

I guess I'll give it a try, but I'll give it until tomorrow to see if anyone has some more information. I'm just wanting to know if the immobilizer is what actually holds the key's chip information, and if swapping it to the new board will start the car.

Iggy

The immobilizer simply relays the code to the PCM. The PCM is the unit that has the stored key code information.

Check around local locksmith's vs. the dealer, most will travel to you to program the key. If you know someone with a decent scan tool(Launch, Autel, Verus, OTC,etc) you can do it yourself.

Thefireball

So swapping the chip itself won't work?
I'll ask my friend if he has a scan tool. I thought these cars ECU were untouchable though?

Thefireball

Welp, the procedure worked. The new PCM started my car and everything! What didn't work was my 4th gear still. I'm suspecting that the mechanic who rebuilt the transmission doesn't know what he was doing ( as I suspected by the comment he made by the previous owner). Good thing tax return is right around the corner.
AV6 swap, here I come!

Iggy

Couple questions

Have you checked the solenoid on the transmission?

Is the P1607 still showing with the new/used ECU? I'm wondering if maybe the solenoid fried the internal circuit in the old ECU?

Who did you have program the key to new ECU?