O2 sensor codes

[SilverFarmer]

Looking for some insight please. Stock 1998 boxster manual, car was impacted pretty good on driver's rear quarter. 30 miles into drive home from collision center after repair, solid CEL comes on. I continued drive home, another 100 miles. Checked with Durametric, got P0140 - O2 sensor behind cat. converter cyl (4-6). Erased code, drove it again, after 8 miles solid CEL and took it home. Codes were P0160, P1121 and P0140. Cleared codes. Swapped post cat sensors left to right, drove, 24 miles in got solid CEL. Coded P0140. Since code did not follow sensor I cleared code again. Today drove 28 miles, car up to operating temp, no CEL ---until I hopped out at home to open the garage door. Didn't turn car off, hooked up Durametric got code P0140. Also captured actual value graph of all 4 sensors.

My question is does this graph tell me anything? Any thoughts or suggestions on what route I should take? This is the first time I have had to use my Durametric so bear with me!

Thanks.

[Homeoboxter]

Code P0140 means interruption of signal, you probably know that by now. I would think your wiring somewhere got jammed somewhere due to the collision, I 'd check continuity from the connector pins to the DME. Those pins sometimes can move within the connector, this can also cause this kind of failure.

As for your picture, it's hard to see what's going on, a video woud be better. What I can make out of it seems fine though. Your pre-cat signal should be oscillating between 0 and 1, while your post-cat signal should be a relatively flat line. So, I would think the system was working fine at the moment of taking the recording, and it threw the code while you were driving when the signal got interrupted.

[SilverFarmer]

Thanks Homeoboxster! When it warms up tomorrow I am going to check this out. Another chap suggested this "interruption of signal" too. I'll let you both know how it goes. Thanks again.