Engine power reduced 4.3l

[Kyledempsey1]

Hey I got a 2009 Sierra 4.3l 2wd. Just bought it a few months ago as a second work truck. Everything was fine for a few weeks then all of a sudden the battery light came on. Swapped batteries out with my 2018 didn’t help. Bought a new alternator didn’t help. Cleaned all grounds didn’t help. Replaced the fuse able link by battery and cleaned connections didn’t help. Gave up and just drove with the battery light on without problems. Week later engine power reduced started popping up. Truck won’t move  disconnect battery works fine for a bit then limp mode again.
 

  Took it to my mechanic he put it on the scanner and every possible code popped up. Crank sensor, knock sensor, o2 sensor. He tried swapping out the crank sensor, throttle body sensor and a bunch of other things off a truck he had at the shop. Nothing helped. Tried another computer didn’t help. The engine is showing it’s at 80% load at idle. He gave up.
 

  Just brought it home and beat the piss out of it for about 20 minutes down country roads Bouncing over potholes, kicking it sideways on dirt roads, basically driving it like I stole it. Worked fine. Couldn’t hurt it. Everything works as it should. Just the battery light on. Shut it off. Started it to instant engine power reduced.  
 

anybody have any idea what’s up?

[CamGTP]

Typically when REP happens, it would trigger a specific trouble code for that reason. So having a scan tool at that exact moment would be ideal.

 

Hard to say if the issue you are seeing is also the cause of all the other codes popping up at once because of a voltage issue that triggered them all.

 

I believe there is a current sensor on one of the battery cables going to the battery, I wonder if that is a possible cause for the battery light because the alternator is good and so is the battery itself.

 

[Kyledempsey1]

22 hours ago, CamGTP said:

Typically when REP happens, it would trigger a specific trouble code for that reason. So having a scan tool at that exact moment would be ideal.

 

Hard to say if the issue you are seeing is also the cause of all the other codes popping up at once because of a voltage issue that triggered them all.

 

I believe there is a current sensor on one of the battery cables going to the battery, I wonder if that is a possible cause for the battery light because the alternator is good and so is the battery itself.

 

Cool going to look for that sensor and try replacing it. I’m sure it’s pretty cheap. If not my mechanic recommended an electrical mechanic shop close to me I’ll have to bring it there

[Kyledempsey1]

Update- I unplugged the current sensor and haven’t had a problem since. I have a new current sensor just haven’t had a chance to put it on yet