I have a 2003 2500 lb7 with 216k. i just completed a injector swap 2k ago. eberything was going good no issues until Sunday. while towing my boat home (5500 Lbs) i went into derate and was limited to 2k rpm. when i got home i read the codes and i got p0206 and p2146. after the truck sits the faults clear and i can runs fine until it gets up to operating temp. the the light comes on and limp mode. is it an issue with the ficm or EDU?
2003 lb7 Help!!!!
- Thread starter StockLb7
- Start date
This will not be an ECU problem. It will be either FICM, wiring harness, or the injector coil itself.
I had this happen on my truck right after I installed new injectors. Turns out I spaced out and forgot to tighten the wires on one of the injectors. It made good enough contact when the engine was cold, but as soon as it started warming up, it would throw the code and shut off half the cylinders.
Ended up pulling the upper valve cover and actually screwing the wires on to that injector, then all was well. The annoying part is when I would measure the injector with a multimeter, it matched the rest of them.
So you can try a different FICM if you have one laying around, but might end up pulling the valve cover to look at the suspect injector. Might as well try measuring it with a multimeter once it gets warm and throws the code. Maybe you get lucky and see high or low resistance compared to the rest.
I had this happen on my truck right after I installed new injectors. Turns out I spaced out and forgot to tighten the wires on one of the injectors. It made good enough contact when the engine was cold, but as soon as it started warming up, it would throw the code and shut off half the cylinders.
Ended up pulling the upper valve cover and actually screwing the wires on to that injector, then all was well. The annoying part is when I would measure the injector with a multimeter, it matched the rest of them.
So you can try a different FICM if you have one laying around, but might end up pulling the valve cover to look at the suspect injector. Might as well try measuring it with a multimeter once it gets warm and throws the code. Maybe you get lucky and see high or low resistance compared to the rest.
There are probably some external ways to test the FICM with special equipment, but I don't know what/how. I have a spare FICM I use to diagnose issues like this. You don't have to even remove the original one. Just wedge the spare one next to the original and move the plugs over. The diesel running through the FICM is totally unnecessary, so no need to mess with that.
You were right. it was one of the wires on injector 6 that was not tight. thanks for all the help. After checking the entire wire harness and not finding any warn spots and checking ohms at the harness going under the valve cover. The last thing i could do is pull the valve cover. Thanks again.
Glad you got it fixed, and sorry you had to open it back up. I remember how frustrated I was when this happened to me. I suspect neither of us will make this mistake again :hug: