P2503 + Coolant
 

Background: 2005 4x4 4.7L w/5-45RFE, 101k miles, only mod is a Superchips programmer (no tune loaded at the moment).

So today, about a mile from home, my Check Gauge light came on. I immediately checked all gauges (go figure). The only thing not normal was that the voltage gauge had dropped to zero. I proceeded to drive the one mile home and parked in my usual space. When I got out of the truck, there was a hissing noise, along with a slight steam cloud, and a large puddle of coolant under the engine. In the engine compartment, coolant had sprayed on the air filter box, airbox, fan shroud and battery, however, the coolant overflow bottle still showed coolant smack dab in the middle between the Full and Fill lines. The last time I had any issue with the truck was 6 years ago when the water pump let go. There is much less coolant this time along with no melting of belts. Even starting the engine now, the temperature gauge still reads just below 50%.

The only code the key trick revealed was P2503 (Charging System Voltage Low). My initial thinking is that either a hose let go or there is a blockage in the cooling system and that the coolant spraying on the battery caused the charging system code. Or maybe I overfilled the damn thing and it made its displeasure known in an obvious way.

Basically, tomorrow, when I get off work, I'll be digging around the engine to see what's wrong. But, if any of you fine fellows have a suggestion on where to look, so much the better.

Thanks in advance for the help, and sorry for the long-winded post. Happy weekend to you all.

Sounds like a hose busted.