2000 2.2L Sonoma - Code P0200 - ECU/PCM, swap or MOSFET replacement?
Hello all,
So I got a 2000 2.2L Sonoma with code P0200, and cylinder #4 fuel injector flooding the cylinder. Troubleshooting and process of elimination has narrowed it down to the injector driver inside the ECU/PCM being always 'on', meaning there is always a 'circuit to ground', thus the injector is always spraying fuel. This seems to be a known issue with this vintage of vehicle, even if not common. I'll use "ECU" below but mean ECU/PCM since I understand the one hardware module is essentially both. It seems I have two options.
#1 - Replace the ECU.
#2 - Open up the existing ECU and replace the injector driver.
Hoping you folks can provide comments for both.
For option #1 it seems I need to find a new or used ECU, have its VIN reprogrammed. However I understand it doesn't end there, and that you need to initiate some sort of modules resyncing, meaning the ECU and other modules need to be resynced, or rekeyed, or something.
So my first set of questions for #1 are like this: what do I need to do, and what equipment do I need to do it? Also, is there a company in Canada or USA that does at least some of this, and helps make the whole process much easier? If yes please provide info.
For option #2 I am unable to find info that easily identifies which component on the ECU circuit board contains the injector driver. My quick math tells me the current through an injector is in the range of 1 amp, versus say low milliamps, so that suggests to me the component providing the injector driver circuitry is a larger external package MOSFET (typically has a metal side for heat sinking), versus an Integrated Circuit (IC) type chip. But I really don't know. I'm trying to follow the printed circuit board (PCB) traces, from pins #75 & #76, but with all the stuff on the PCB, and itty bitty traces, I haven't been successful so far. I am assuming it will be a component that I can desolder, remove, replace, and resolder, but that is yet to be seen.
So my first set of questions for #2 are like this: has any of you done this before? What component contains the injector driver? Is it an IC, or is it a larger external package MOSFET? Anyone have any pictures? Is there a company that does this and I can simply mail them the ECU and they send it back?
With the various engine swaps going on, I am guessing #1 may actually be the easier way forward, even if it sort of have more steps, and more $$$ involved.
Please help. I should add this is a project truck that my son and I, and a dear uncle of his, are working on. It would be sweet to see that P0200 code clear and have a nice smooth running engine assuming no other issues with it of course haha!
I'd also like to understand what causes the injector driver circuit to get like this. It's MOSFET based I understand, so it's likely blown, thus now a short circuit. What can cause this to happen? I am wondering if I should replace the injectors for piece of mind. However, they all measure the same resistance, and the wiring harness measures fine too, i.e. no shorts. I'd like to be sure I have fixed any possible 'external' issues before replacing the whole ECU or a MOSFET.
Hoping the Sonoma community, and perhaps even the larger GM (Chevy/GMC) community can help. Thanks everyone!