My 2004 D2 has been producing codes for all 4 O2 sensors. The sensors were replaced 2 years ago. To sort out the problem I bought a brand new one to see if the O2 sensors are the problem. The new O2 sensor is producing a code so I know there is something else going on. I have replaced all the fuses and relay for emissions to rule out a blown fuse. I can clear the codes and then watch them come back. First the rear O2 sensors throw codes and then the fronts. I don't know where to turn. Can anyone on this forum help me????

 

Have you checked for vacuum leaks? What type of code reader are you using? Can you monitor the O2 sensors to check their activity? Any other codes?

 

What sensors did you use?
What are the actual codes?

 

I did check for a vacuum leak. I sprayed brake cleaner over the motor to see if I could hear a change. I'm using a Snap On reader with a blue tooth unit plugged into the OBD port. I can monitor the O2 Sensors and they show no activity.

 

The set of 4 sensors I put in came from AB and were Bosch. To dig deeper, I replaced one on the upstream passenger side. It's throwing a code also and does not show any activity on the monitor.

 

I wouldn't think that all four would be DOA, one or two, maybe. Perhaps you have wiring harness or maybe even ECU problems. You mean voltages stay at 0 when you scan?

 

The codes are P0135, P0134, P037, P0141,P0161,, P0139, P0160,, P0155

 

Someone mentioned they might not be working as a result of a bad Mass Airflow sensor. Can someone confirm?

 

I had a similar issue, replacing the sensors numerous times because of codes. Every new sensor seemed to be dead on arrival, despite the Rover running fine.

There is a grey multiplug on the inside fender on the passenger side. Apparently it gets dirty and screws with the electrical signals. I cleaned mine out and I have been code free for 2 years.

I focused on the top part where the wires went into the plug. I used compressed air & electrical cleaner.

It only takes a minute to do, and is worth a shot.

 

Instead of spending money on sensors, spend $5 on an ELM327 and $20 on an old android phone so you can monitor sensor voltages with the free torque app. Once you can chart voltages, we can help you troubleshoot better.