SOLVED: Inactive o2 sensor - help needed!

Solution was buying an original Bosch Lambda sensor from Autodoc.

 My MGF MY2000 with a MEMS2 VVC engine has failed its MOT on emissions. They are way over what they should be. I've changed the o2 sensor for a new one from Rimmer bros, changed the cat and coolant temp sensor but it failed again.

The oil temperature gauge on the dashboard is not working so I suspect the oil temp sensor near the oil filter is not working. Is that connected to the ECU in any way?

I've logged some data using the P-Scan and can see the o2 bank 1 sensor state is inactive and the voltage stuck at 0.49v. I'm assuming something similar causing the ECU to go into a default mode which is overly rich causing the emissions problem.

It starts fine, idles and runs well but I'm stuck. Any ideas? I've attached the log to this post if someone gets a chance to take a look TIA.

This is the only error code:

"Current error codes:-
Oil temperature sensor *

Historic error codes:-
Oil temperature sensor low *
* depending on model
Press Erase button again to confirm"

I've noticed the "Inlet valve open angle" is 700 degrees, does that sound correct?

G'day and welcome to The-T-Bar. 
Please feel free to use our checklist for new owner and members:  https://www.the-t-bar.com/forum/54-how-tos/99326-a-check-list-for-new-owners  It won't help you with your current emissions problem by may help you with other concerns.

The oil temp gauge on these things is useless at the best of times and the damned things rarely work properly, it's not going the effect the emissions.
I myself have a MEM/S 1.9 car so I don't know what the normal figures for a MEMS 2J car look like. but someone who does will probably be along shortly.


 

I've ordered a new oil temp sensor to see if that makes a difference.

Also ordered another original lambda sensor to see if both of mine are dead...

An o2 sensor should alternate between 0.2v and 0.9v.  I believe that 0.4v is what you can expect when there is no o2 sensor present at all. Maybe you have a bad wire or connection or something.

Update on my issue. I replaced the lambda sensor for an original X-Part version from Rimmer Bros. I also tested the continuity of the wires from the square plug to the ECU socket and they are fine.

The lambda sensor stuck at 0.49v is still happening. I'm stuck as I've changed all the engine temp sensors and they are reading correctly in P-Scan. All other data seems to be fine.

The lambda voltage should fluctuate between 0.9 down to 0.1 when hot & at 2500 RPM. My guess is that you already knew that, how are you measuring that voltage? An old fashioned analog meter will show the voltage fluctuations, however it would need to have a high input impedance or it could affect the reading. A digital DVM is fine but the numbers will be all over the place. I did some work on stoic values & built a 12v oscilloscope optimised to look at junk like this but as I’m away at the moment & 200miles away from my notes, I can’t help other than that.
M

I’m using a P-Scan to monitor the voltages the ECU is reporting.

I do have a small oscilloscope that I could put on the sensor wiring to see what that is outputting, that might then eliminate the sensor and wiring which would point at the ECU failing.

I be inclined to think it's not the ECU.......they don't fail often, any problems are usually elsewhere

on the MEMS2 and MEMS3, if you only select one parameter (such as lambda sensor voltage) it will update much faster.  Given that you are looking for a fluctuating input, it would seem like a sensible way to monitor it.

Also (from memory) there is a mixture control status which can be open loop (not controlled by the lambda sensor) or closed loop (is controlled by the lambda sensor).  So you are looking for it to be closed loop.

Still no joy with getting my o2 sensor to go active. I bought a VVC ECU and 5AS alarm module. Connected up and the car starts fine with the new ECU, but still no o2 sensor.

I've ordered an original Bosch sensor to try next, beyond that I'm stuck. I may reach out to KMaps to see if they can help diagnose remotely.