Recently purchased 03 Disco (Non-SAI) showing Bank 2 02 no activity faults - Torque app graphs confirm no activity on bank 2, normal activity on bank 1. Swapped 02's side to side and problem stayed on bank 2. Unplugging sensor did nothing (not that I expected it to, but I guess I hoped it would go to 0 volts. Used DVM to check ohms on wiring from 02 sensor plug to ECU plug - all wires checked ok with close to zero resistance.

Since the wiring seems to check out, and the sensors work in bank 1, I am left to conclude that somehow the ECU circuit is bad (although that would seem highly unusual and unlikely)?

Has anyone else experienced this? Is there some other possibility I am missing? Is it possible to run the truck with connector c0635 disconnected and check the 02 voltage on the plug to confirm normal operation (0-1v output with engine running)?

I have a spare ECU and BCU from a 00, but I'm guessing I would need to reprogram and even then the program is probably different from the 4.6 in the 03. Also have another running 03 I could swap ECU & BCU with, but it is a SAI model with different equipment (SLS).

Any similar experiences worth sharing would be appreciated!

Thanks

Tim

 

Dude....just went through this exact issue. My passenger side front O2 was registering dead for a long time. Never dealt with it cause it didn't seem to effect anything. Eventually I started getting random misfires and a significant fuel consumption loss and ruff idol. I couldn't figure it out in my driveway and paid a mechanic 4 hours labour to diagnose the issue. It ended up being a short from the ECU that was sending bad signals...or no signal to my O2. Installed a used ECU and it fixed the problem right up.

My biggest pain in the *** was that I couldn't get the nanocom I borrowed to sync the ECU. Ended up finally going to a mechanic who did it in seconds. I only installed the ECU not the ECU and BCU.

That was all about two weeks ago and i've been code and problem free since....frigg I just jinxed myself didn't I?

 

Thanks for sharing your experience!