2006 4.3 P0200 code, running rough

[BleedinBowties]

Hello all,
I'm a bit stymied with a problem in my 2006 1500 W/T with a 4.3L. This is the old 4.3 before the new engine series, an LU3 I believe, with about 170K on the clock. It began running a little rough a couple of weeks ago. I knew the plugs needed replaced (pretty sure they were the originals because the upper electrodes were basically gone) so I began with that before I every put my OBD2 scanner on it. At the same time I replaced most (4 or 6) plug wires. Yes I need to replace the other 2 but I don't think that will fix my issue. At the same time I replaced the EVAP purge valve because I broke it while crawling around under the hood. I fired the truck up and it seemed better but still running rough. This time I checked the OBD2 and it was giving me a P0200 which indicates an injector circuit malfunction. I cleared codes several times and rescanned and am only getting that code.
I checked wiring under the hood, can't find anything loose or broken but that doesn't mean there isn't something under there. I feel like leaning towards the spider injector being bad, but I don't want to through parts at it willy-nilly, and thats alot of work if it's not bad. I have a set of NOID lights on the way to help me diagnose that area, but if my thinking is correct then all those will tell me is if the signal from the PCM is bad, right?
I do need to crawl under and change those plug wires and check grounds, etc, but those things not withstanding, I guess I'm looking for help on the diagnosis side. Is there any way to check injector integrity without tearing out the spider? I can't see one. Any help would be greatly appreciated.

 

[stutaeng]

That's a circuit code, which means the ECU has detected something like an open or short on that circuit. So it could simply be a broken wire on the harness, poor ground or loose conenction.

Find yourself a scanner that has bi-directional controls and along with a fuel pressure guage, do an "injector balance test." When I was just learning diagnostics, I spent like a whole summer chasing a lean, bank 2 code on my 00 K3500 beater. I was checking with a DVOM because that's all I had then, but all the sensors were checking out ok. I was like you and not wanting throwing parts at the thing. I finally decided to go buy a basic hand-held scanner that had live data and the injector balance test and after watching some YT diagnostics videos, I quickly ruled out vacuum leak. Another 15 minutes and the injector test revealed a dead injector #7. New spider fixed that. Could I have just bought a new spider? Yes, but that would have been a lucky guess...sometimes you get lucky, but often not.

The injector balance test will likely reveal the injector with the fault, and that way you can narrow down where you look.

You should have also a lean code (or misfire), if that injector is not firing, but I have learned on the SBC-based engines the ECUs don't always throw these codes.

 

[BleedinBowties]

Thanks so much! I learned more from your response than a week of searching posts on the net. I agree, I could just change the spider and possibly fix my problem, but if it doesn't fix it then I'm left more frustrated. can I ask what brand/model your scanner is?

 

[stutaeng]

Thanks so much! I learned more from your response than a week of searching posts on the net. I agree, I could just change the spider and possibly fix my problem, but if it doesn't fix it then I'm left more frustrated. can I ask what brand/model your scanner is?

It's a Innova 5610 that I bought at my local AAP. It's "okay" but kinda of expensive for what it is.

Years later I bought a OBD2 Dongle based on some YT diagnostics channel, don't recall which channel: https://www.amazon.com/TOPDON-Bluetooth-Diagnostic-Performance-Bidirectional/dp/B0C3QQYQ1B/ref=sr_1_6_pp?dib=eyJ2IjoiMSJ9.ZHr9Zv5aj8P_PYPL7ku69X-4IxfPsUiLV1Zg1oAOcryHZ8RrRTWc0n1SES0Sk6-2a7NQ8AQiDqnXCYsDe8zVyhHgh7BWA0Pha1As579A_FnwVBMdf_-gCDTqT00NZLksu68OzgNWTDUley2kI0zwo9Zb7jnoxvkhDKsELVBaveKFAh-MtcHTGLRtZIY_5dFYzkywIa5tLLOuAH9ttEBEyoZwD0yOuj1ewu5Y1cz3SoP_ShVJ-7Ox-02QEZyBwkWNg8JPYTkIjO2WS-arSM21xI5BqvGJUqru8-cKqxQm9SY.gmk2ef00bmQrpUciurPEFQRmGzDKcu2oRvVpj6DnDJ4&dib_tag=se&keywords=obd2+bluetooth+adapter&qid=1763759846&sr=8-6&th=1

It blows away the Innova on the functionalities. It has misfire counts, and a bunch of interior by-directional controls the Innova does not. The only drawback is it comes with only a 2 year (?) subscription. But at that price, you can just repurchase. I haven't tried to use it mine in a while, looks like I purchased it in November 24, 2023...

There are so many good scanners out there for the money. Autel sells really good ones for the money, and I'm sure others as well.

 

[stutaeng]

Also, if you haven't already done so, look here for free online diagnostics procedures and wiring diagrams:

P0200 — 2006 Chevrolet Silverado 1500 2WD V6-4.3L VIN X Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Silverado 1500 2WD V6-4.3L VIN X.

charm.li

System Diagram — 2006 Chevrolet Silverado 1500 2WD V6-4.3L VIN X Service Manual | Operation CHARM

Detailed repair manual for the 2006 Chevrolet Silverado 1500 2WD V6-4.3L VIN X.

charm.li

 

[BleedinBowties]

Cool thanks for the information! I did take a peek at charm.li. Always forget about that site...what a resource. I'm not too up on diagnostic tech. I have a dongle myself but doesn't give great data...really just basic stuff. It might give more but I'm not schooled on how to read or access some of the data the app might provide. I think it's pretty basic though. I'll take a look at some of those you mentioned. Thanks again!