what causes a 2509 code
 

ok what would cause this code i have seen some say bad ground and some say its the batteries but mine are reading 10v with key on is that the problem.

When turning the key to start it just clicks.

P2509 ECM/PCM Power Input Signal Intermittent

Need at least 12V to the ECM at all times, otherwise it throws that code. How old are the batteries??

what causes a 2509 code
 

Not sure how old the batteries are.

Judging on the issue, likely the ones that came with the truck.

what causes a 2509 code
 

No they are not factory batteries I can't remember right off hand but I think one is a super start and the other is a yellow one

Need to be the same type and cranking amps need to be also. Type as in wet or dry cells, can't run one of each at the same time.

Best bet is to get two new batteries.

thats kinda what i was thinking. also does the odometer stay on all the time on these trucks?

Odometer come on when:

The drivers side door is open, key or no key in ingnition
Key is in ignition, but switched to accessory
Or the switch is in run, engine running or not

what causes a 2509 code
 

When door opens no key in ignition

Normal. Service guy can get a reading faster/easier.