2005 T190 shuts off intermittently- 3 beeps and Code 77-48

Hi there, New to the site. I have a 2005 T190 Bobcat that is driving me crazy. It was working flawlessly and now shuts down intermittently. Sometimes after a few minutes and sometimes after running for hours. The serial number is a 5277xxxxx. It beeps 3 times and then shuts down immediately like the keys been turned off. No warning just stops. It will then start right up again when I restart and then shuts down almost immediately. It sets a code of 77-48. Does anyone have a wiring diagram. I have ordered one but it’s a week away. Any help would be greatly appreciated. Thanks