LLY Limp mode - P0203 and P2149

[NevadaLLY]

Wow, I was expecting 12vdc, apply command voltage and look for output. That is way more than I expected - I’m on the road the next couple days. Will probably send it to SIA since I continuity checked the runs from the ECM to FICM to injector and all was ok.

It’s interesting it’s just P0203 and P2149. Most posts I read have more codes set. It’s not tripping the EDU fuse, so it’s powering up for sure. Maybe just a partial failure.

 

[2004LB7]

The mosfet that controls that injector could be bad. If SIA says it's bad but can't fix it, send it my way and I'll give it a try. You can't always trust that if they say it's good that it is indeed good. I sent one back that they said they fixed but didn't work. 2nd time after explaining the issue they said they couldn't fix it

 

[NevadaLLY]

I'm about to go down the FICM replacement route. Quick question - I see a PN difference on two available for the LLY. What's the difference? Is one a rev change that's more reliable that will still work? Mine is 97303751 but I'm seeing 97303753 also available saying LLY.

 

[2004LB7]

Don't quote me on this but I think they are each for the Silverado and Sierra part numbers. But I do know there is no difference between them and are interchangeable

 

[1FastBrick]

Don't quote me on this but I think they are each for the Silverado and Sierra part numbers. But I do know there is no difference between them and are interchangeable

Could it be 1 for GM and 1 For IZUZU ?

 

[2004LB7]

Could it be 1 for GM and 1 For IZUZU ?

That could be it. Didn't find much information on the 97303753 part number. Just that it was listed along side the other part number on a few sites. But all the reliable sites all show 97303751 as the correct part

 

[1FastBrick]

That could be it. Didn't find much information on the 97303753 part number. Just that it was listed along side the other part number on a few sites. But all the reliable sites all show 97303751 as the correct part

I never paid attention to the part number but I did notice the sticker on the Isuzu has Isuzu on it but the GM ones don't

 

[PureHybrid]

SIA is on everyone's hit list it seems, shady deals supposedly from a few guys on the bookface. Good reviews from Re-circuit Electronis or Z-Tech. The guy at Recircuit has an LLY truck to test them on when finished

 

[NevadaLLY]

I ended up buying one so will follow up if that was the fix. I couldn't get ahold of SIA and really need this thing back up and running. I'll probably send the old one out for repair anyways...

 

[2004LB7]

Let us know if it works.

 

[NevadaLLY]

Quick update - the FICM I ordered hasn't shipped out and was supposed to be here Friday, so refunding that. I just found another LLY in Reno to test my computer on - luckily the guy is cool with me plugging my computer into his engine to see if it throws the same codes. I also just spoke to an electronics repair shop who can turn mine same day so once I verify on the other truck, will send out for repair at that shop and hopefully be back up.

 

[NevadaLLY]

Sooo, not all folks are as big enthusiasts as we are. Turns out his was an LB7. Oh well. Sent the FICM out for repair and should have it back by the weekend. I’ll post an update then.

 

[2004LB7]

Sooo, not all folks are as big enthusiasts as we are. Turns out his was an LB7. Oh well. Sent the FICM out for repair and should have it back by the weekend. I’ll post an update then.

I was a little surprised when you mentioned you found some close that was willing to loan you his truck for testing as these trucks are getting harder to find and they were not as common as the other years to start. So it makes sense it was an LB7. Sucks you weren't able to test it

You could have driven down here with your FICM, tested it and be back home by now

 

[NevadaLLY]

I was a little surprised when you mentioned you found some close that was willing to loan you his truck for testing as these trucks are getting harder to find and they were not as common as the other years to start. So it makes sense it was an LB7. Sucks you weren't able to test it

You could have driven down here with your FICM, tested it and be back home by now

I know!! Haha I guess that’s what I get. But Friday will be the day! And the computer that went missing apparently now has tracking so I might end up with 2 good units. If that turns out to be the case, the 2nd will be for sale.

 

[NevadaLLY]

So, the rebuild on the FICM was done and it is not throwing codes on his setup. However, he did the repair based on my notes and looks like only capacitors changed. Didn’t find any issues with the get fet on the injector 3 circuit and also didn’t run it to see if codes set first. So I guess it’s a wait and see when it gets back. Nothing definitive yet

 

[NevadaLLY]

Guys, known good FICM installed and still throwing same codes. New plug on INJ 3. I’m lost.

 

[2004LB7]

Start back at the beginning of the thread and see what you missed or didn't test. Might be time to invest into an LCR meter

 

[NevadaLLY]

Fellas, I’m really thinking this injector was actually the issue all along. Can anyone confirm if bench testing the solenoid vs FICM driving is the same or different? For instance the bench isn’t as sensitive and could run the solenoid where the FICM would not? Just a theory. I haven’t had a chance to start swapping injectors again but that’s the next step. I’ve gone through all the wiring, all the connections. Everything shows good still.

 

[2004LB7]

How are you proposing to bench test the solenoid?

Buy a cheap LCR meter and prob your injectors. Typical values are about 120mH. Straying too far outside this will cause the FICM to throw codes. Even if it technically would work. Solenoids with internal shorts will read lower. An ohm meter will not be any help with the solenoids as the resistance is too low already. You need to test inductance

You can probe all of the injectors from the FICM harness connector. It will read a little higher because of the harness but should still show which one(s) are low

Have have this meter and it does the job

https://www.amazon.com/gp/aw/d/B07CYSV5LY?psc=1&ref=ppx_pop_mob_b_asin_title