I cleaned the battery posts and cable connectors, still won't start. I will check the chassis side connections next, thank you.

I sanded and cleaned the neg connectors on the chassis and the engine. I checked the post cable connection to the starter motor and it is tight. The 3-2 yellow code is gone but the low engine oil pressure light continues to blink erratically. I did not think to mention this red light earlier, sorry. Still won't start.

Not cranking at all. I think I am hearing the fuel pump but that is it. PTO? This is a Z997 zero turn lawn mower. I don't think there is a PTO. I changed the oil myself Just 2 days ago, right after I found out it would not start. I just now check the oil level and it is up to the full mark on the dip stick. The last time I had this in to the dealer was 2016 because it would not start. They put in a new battery. Even though the battery shows 12.97V using the multimeter, could it be that it needs to be replaced?

Also the parking brake is set, the handles are apart, and mower engage knob is pushed in, and I sit on the seat when turning the ignition key.

Thank you, SGR. Really appreciate your taking the time to talk me through this. I am thinking it is the battery and will take it down tomorrow or Tuesday and have it tested, or maybe just get a new one.

Ok, will do. Thanks again.

Good to know thank you. I am taking the battery in tomorrow to the John Deere dealer for a load test, assuming they will do it. If it fails, which is what I expect, I will replace with a JD battery, hopefully a Strongbox.

dj2520, I Googled replacement batteries and many people think highly of the John Deere Exide built Strongbox batteries. Hopefully they honored the warranty for you. I wonder if there is a Lithium Iron Phosphate battery that would fit in a 997.

I found this on Amazon: Eastup 1250750 Lithium Iron Phosphate (LiFePo4) Automotive Replacement Battery 12V 50AH, Cold Cranking Amps (CCA) 750A, 640Wh 10+ Years Lifetime. …

dixie460, Your post is basically what I expect to see in a lead acid battery. Maybe as much as 12.9 volts when fully charged and about 11.4 volts when fully discharged. When the engine is running maybe 13.7 to 14.7 volts. Looking at my records on the 997, I had this same issue with not starting in 2016 and had the original battery replaced with a JD battery. I purchased the lawnmower in 2010, so about 6 years on each JD battery. I have Battleborn lithium iron phosphate batteries and solar panels on my travel trailer, and see a float charge of 13.6 volts or so.

I use battery maintainer's all the time on all my batteries, for many years. Except the Lithium batteries, that is. Confession: Had my 997 hooked to a maintainer with alligator clips over the winter. Walked by it every single day and looked at the maintainer blinking and to be sure the clips on on and to check for critter nests. Every single day for a solid 4 to 5 weeks, before I realized I put the (black) negative alligator clip on to the positive post on the battery, and the positive (red) alligator clip to engine block. I don't have an excuse.

Success. Took old battery into JD dealer. Load tested at 7 to 8 volts. Bought a new JD batter group 47, $119. Installed and it started right off. Also changed the 2 air filters. Thank you to everyone who responded.