Thanks for the reply!

I went to autozone website and looked up its Diagnostic Trouble Codes and here is what it says:

DTC P1518 sets if the battery voltage is low. If the customer's concern is slow cranking or no crank due to low battery voltage, ignore the DTC P1518. Clear codes and retest.
DTC P1518 also sets when there is a short to B+ on the TAC module ground circui.

The battery is new, so we can cross that one out.

My husband is taking it to autozone to have it re read. Hopefully he can come out with a definate answer...(fingers crossed)

btw...thanks for letting me know about driving cycles!

 

Not sure how much stock I would put into this because if B+ was shorted to ground than you would have a blown fuse some where.

Unfortunately in the car world nothing can be ruled out until you verify it. The battery is only the starting component of the vehicle. After the car is running the alternator is what powers things and keeps the battery charged. For a low voltage condition you could also have a weak alternator, bad connections at the battery, bad connection at the alternator or even a bad wire from the battery to the alternator. Or not to mention one of those back in the day sears batteries (old batteries put back on the shelf) For a low voltage situation the easiest way to tell is put a meter on the battery while the car is running and read the voltage.

You will still not have a definitive answer because diagnostic trouble codes (DTC) only give you the area of failure and not the specific cause. You have to test the components involving the DTC to verify what actually failed.

 

DTC P1518 - Diagnostic Chart


Sorry for some reason the link didn't appear

You will need both links if you want to diagnosis the issue. The DTC link will step you through what needs to be tested and the wire diagrams/service manual will give you the wire colors that the diagnostic chart talks about.