I have a check engine light on and when plugging in my reader it will not turn on. I tried multiple code readers and none would work. I checked across the pins and had power, checked fuse which was good, and checked the ground on the valve cover. I then cleaned out the plug with electrical cleaner and now when I plug the reader in the screen flashes for a split second then turns off again. Any ideas on what’s going on or what to look at next?

 

Try unplugging the CPS before plugging the code reader in.

 

I had that problem with my XJ when I 1st got it , ended up to be a bad abs computer all I had to do is unplug it and then the OBD2 plug started working .

 

Doesn’t have abs computer. Tried unplugging cps and did nothing.

 

Also I think the OBD2 plug shares a fuse with the power outlet / cig lighter .

 

For anyone wondering, I found the issue. Motor was swapped in 1k ago right before I bought it. Previous owner forgot to put the ground back on the block and had something else grounded to that pin. Found the ground wire tucked back behind the block

 

Nice job!! Thanks for reporting back.