Hey guys, 08 250 is throwing a code p-1633 it means low voltage, but everything seems to be o.k.. The other day I ran the batteries down but not too low so I put a charge on them. The computer says the alternator is o.k., but when I clear the code it comes back in about a minute. Anybody have this experience? Or does someone know what to look for? Thanks.

 

Chassis ground or corroded battery terminals? You have to have a good (low resistance) path for the current otherwise there is a voltage drop. If the chassis ground is clean, check for a voltage differential between where the PCM picks up it's ground and the panel (probably fire wall) the engine grounds to.

 

It is a brand new truck, no corrosion, grounds good, I also have two batteries. I am thinking a possible short cicuit somewhere, the dealer replaced the fuel pump last week and the gauge is stuck at the halfway point.

 

With all the power mods you have, I would think dual alts would be something to think about.

Where is La do you live? I live south of Lake charles.

 

I wish I had the dual alternators, but I did not order the truck so it does not have them. I keep the batteries charged up by putting them on the charger every couple of weeks, and I don't have any problems. On my last truck I had three batteries and the alternator burned up, so I put an 140 amp and it worked fine. I live in the new orleans area down by lafitte across the bayou.