Hi all tried to find answers via search but typical stuff like checking fuses and connectors haven't works.

I tighten up all the connections at the obd2 port and the scanner powers on, ignition turned on or running and it won't connect. Tried a scanner that works fine on my other vehicle.

It's a 1997 b3500 with the 5.9l. seems to be running fine but threw a code today and I can't read it. Any ideas?

 

what scanner are you using alot of them will only go 15-20 years old or have to buy the subscription for that make. But other than that check what pins do what and double check them i usually try blowing it out with a airgun and brush and check the harness they come loose all the time

 

It's just some cheapo scanner from Amazon but the one at AutoZone didn't work either and I've used that on older cars

I'm not really sure what to check but I disconnected the harness pulled each wire from the harness tightened up the connector and put back in and no dice

 

Some of the newer scanners read CAN Bus PCMs and won't read OBD-II ones. Have you tried the key dance method to get the codes via the blinking CEL?

 

Key Dance: Have a paper and pen ready to write down the codes. Start with the ignition off. Within five seconds, switch the key on, off, on, off, on. (On not Start!)

The check engine light (CEL) will flash. Count the flashes Each code is a two-digit code, so a (for example) 23 would be FLASH FLASH (pause) FLASH FLASH FLASH (long pause) It will never flash more than 9 times, watch for pauses!

55 is end of codes - it's normal, and 33 is normal on earlier models if you don't have air conditioning.