Someone help ID the code from an OBD-II Scanner?

We used an OBD-II scanner to identify the problem on our '98 Chevy Astro Van. The code it gave was P1351. The vehicle won't start/run. We have looked online for the code ID but all the codes we get are for a 3.1 engine. We need the code for a 4.3 ENGINE. Is there any way you can pin-point exactly what the problem is? or know where we can find the code's ID?