Been battling the o2 sensors in my 1999 Discovery II for a while now. I have two new O2 sensors for the front. It is throwing codes 130, 134, 150 and 155.
Is there an inline fuse or fuse somewhere that could be the problem?
Also, is there anyway to bypass these things to get it inspected. I have had this thing sitting in my driveway for going on two years now.
It is isn't the sensors, then what?
Any help is appreciated. Thanks in advance.
Doug

 

Had similar problem. Throwing 134, 135 & 155 before & after replacing all 4 sensors. Turned out to be on the Dr side female front plug, 1 of the prongs (contacts) was pushed in. That fixed them all. I'd suggest cleaning all your contacts and inspecting the front plugs to make sure each has 4 prongs.

 

Mine turned out to be corrosion in the front passengers side. It had contamination from oil and muck. I used that electric cleaner and all is well. Took me over a month to figure out.

 

I would start with cleaning the connections. If there is oil in them, better fix your leaking valve covers.

 

I have read that most failures occur at post cat. Amazon has OEM Bosch for $45.80 #15630. Cheap in retrospect. Do not yank the plugs. If they don't disconnect easily, make sure that you are pressing the tab the correct way. In all cases - RTFM. Manuals are available all around this site. After cleaning you can use dielectric grease to insulate from a repeat failure. Also, Is your MAP (mass airflow sensor) clean and working? If it looks dirty, clean it using the proper cleaner. If it doesn't help, it ain't gonna hurt. Don't give up on it and let it rot in the driveway.

 

I'm still battling this thing. Unbelievable. Checked all the prongs and all were good. Tried to check all the prongs with a test light but got to thinking if one went to the computer it might not show up anyway. BTW, on both sides, 3 prongs lit up the light one did not. Figured it went to computer control. I would think as brilliant as some computer guys are, there would be a way to bypass or trick these things...someway???????? Any other ideas?

 

OK, let me go at it this way;
The wires are white, brown, red and orange. Which color is for the o2 sensor heater?
Maybe I can trace the problem that way as it is throwing codes 135 and 155.
Thanks in advance.

 

If I took it to a Land Rover dealer/service center, what would they do? Any other ideas?

 

Tell you your muffler bearing are warped and try to sell you special floor mats to fix the issue.

 

Lol,
Well, I asked..... and you are right