2000 Honda accord lx. 2.3 Car runs normally with scan tool plugged in. As soon as you remove scantool car does not crank or start. Brand new pgm fuse is installed as soon as key is turned to acc postion relay is activated and does not stop buzzing. No imbolizer light. Fuse appear to be good as tested any one have any ideas?

 

It would be a freak occurrence, but maybe the scan tool locked up a module or and routed it through itself. Maybe try killing power to the ECU for a few minutes and see if that helps. Otherwise, while the scanning tool is hooked up, poke around and make sure you clear everything you asked it to do. Some of the really sophisticated tools are so feature-rich that its hard to know what they are doing. I still have OBD1 so I can advise you from experience, but if your trials definitely show that tool being unplugged/plugged makes the difference you say it does, then focus on what the tool is telling your cars's computer. I always think those tools can only read codes and clear codes, but who knows what the modern ones, and the use-at-your-own-risk smartphone apps can do.

 

Usually when a car only runs with a scanner or code reader installed is because the ECU/PCM is being grounded through the scan tool.
Look for a loose, broken, or missing ground connection in your PCMs wire harness.

 

You have a lose ground my Honda Accord would do the same

 

 

[2022/12/31, 17:03:47] You Are What You Think.: Jokes aside, the problem is usually that the engine is missing a ground connection. So make sure all the grounds are connected, and clean and tight