Hi guys,

Just fired up my L33 swap for the first time, and among some issues (IAC not responding well, high idle, etc), the most pressing issue is that the OBD2 scanner won't connect when the engine is running (or will drop connection once the engine starts running).

Constant voltage stays at 12v even when running. But even if I start the engine, and then plug the scantool in, it doesn't connect. With engine off, no problems connecting. I'm ASSUMING it has something to do with the serial connection (since voltage is 12v even when running) but I can't begin to figure out what it would be?

Anyone encounter this before?

Thanks!

 

I guess I should specify that I have it wired to Pin 2 (serial), 4 and 5 (ground), 16 (Constant power). Which as mentioned, works fine when it's ignition on, engine not running.

 

Might be a voltage issue. Is the charging system not keeping the system at 13.5-14.8 ? I've never had the issue of not being able to connect with “KOER”

 

Thanks for the reply. Alternator is definitely charging. I agree, unsure why it wouldn't work KOER but no problem engine off. (I'll go throw in another P59 right now, but unfortunately it doesn't have a programmable H/w number so I can't do much experimenting with it. I suppose it won't even fire, since I wouldn't be able to turn of VATS. Maybe I can at least compare serial voltages).

 

It might fire and run for a short time. Why are you only seeing 12v?

 

I just meant it was receiving constant battery power (13-14v, whatever it may be at the time). I use a OBDLInk sx to program the ECM. I'll see if I can get OBDWiz or whatever it's called, and see if I can try a different scantool.

 

 

Just as an update, it actually was a bad battery. I guess voltage dropped just enough to click the relay off and on again. We didn't catch that as the issue as the ecu was controlling the engine as it should. (So why it didn't connect, no idea.. But new battery solved it).