O2 Stuck at ~.4 volts on Powerlogger

[joed]

I disconnected the heated O2 I'm using, Powerlogger still reads ~.4V and barely moves. Plugged in a stock O2 and hit with torch, still reads ~0.4V, engine on, idling, driving, or just key on, engine off. Must be something in the wiring, it's always worked well as is. I've also checked PL cables and that the board is all the way snug in the ECM. Any ideas where to look? I suppose I'll look at the input board tomorrow. Thank you.

 

[EricM]

When there is no O2 connected to the ECM, the reading will be in the .400's. It is not related to the powerlogger. There is likely a disconnect between the O2 and the ECM.
The stock O2 input is at pin D7 at the ECM connector, and the wire is purple.

 

[joed]

Thanks for quick response Eric. Very helpful, will check.

 

[joed]

ok, I have all my wiring tucked away a little too well. O2 signal lead was unplugged. I figured it was a PL issue since I didn't get a code...wonder why it didn't throw an O2 code?? Drove around 20 miles that way. Hopefully that explains why it seems sloppy rich.
Thanks again Eric, much appreciated.