I started my truck today and got a reduced engine power within 10 sec. Pulled the code p1518. I done a little research and some calling a was told to check for loose wires or broken wires on the DBW system. Couldnt find something that stood out. I even Ohmed the wiring back to the control module and found them to be good. Was told by a very good gm tech to just rewire the 8 wires between the DBW connecter and the control module. So I did still no change, Cleared the codes and still went into reduced engine power as soon as I started the truck. On a hunch I checked the batt voltage and it was good, I then connected jumper cables to my other ride and let it set for a few min. Started the truck and everything is good now. Could my battery being week cause this? Im going to load test i tomorrow and see. I took it on a 30 min test drive and it was fine.
Could this simple week batt cause this?

 

I have received some similar reports.

 

Yes a week or faulty battery could cause this type of issue. Certain parts of the electrical system are very sensitive to voltage change. Even something as simple a corrosion on the battery terminals or post could cause resistance.

I have seen a few cars with electrical issues that were simply fixed by cleaning the battery post. Others had batteries that seemed good but had internal faults within the battery.

Best example I saw was a civic with light corrosion on the terminals. The Anti theft would not allow the car to start intermittently. Car would crank but never start. I went in to the System and looked at the values on the scan tool and compared them to what they should read per the factory spec.

Come to find out it needed to see a value between 3.5-3.9 volts during cranking. It was only getting 3.2 volts. The battery seemed fine but they never cleaned the post on the battery terminals when installing a new battery. I did a voltage drop and measured .8 volts. So I cleaned the post and the terminals and that brought it to .4 volts on a voltage drop. It was enough get it to start and see the minimum 3.5 volts. Still not happy I grabbed a new battery cleaned the terminals and it dropped to .2 volts on a voltage drop. It was now reading 3.7 volts in the Anti theft system.

 

Small update! I found the ground wire on the passanger side head smashed between the bell housing and the block. Its all good now after crimping a end back on and bolting it back down

 

Ah, nice find! Glad you got it found & fixed!

 

Thanks for the update!!! Glad you found it.

 

Im so glad I found it. Such a simple problem can cause so much BS. IF anyone has this problem check your grounds several times I overlooked it twice. Its hard to see back their

 

Yes it is, and good find. More often then not you find something stupid, the question is how many times you will overlook it before finding it.