Hey Disco 2 guys,

I have a 2000 Discovery 2, Need to pass inspection as it got rejected. The codes are: P1590, P0154, P0135, P0155, P0140, P0141, P0161.
I replaced all 4 o2 sensors, Also I cleared the codes before installing the new ones
I know I installed them in the right locations (Upstream/Downstream)

Whats next on the list to troubleshoot?
Can someone tell me which each code means?

 

Download a PDF copy of the workshop manual and search in it for the codes. The link to the workshop mammal is in my signature below.

 

So...you had these same codes...before and after changing 02 sensors? Did you get the plugs seated properly and check to make sure you didn't push any wires out of the plug during assembly, very common issue. If all of these codes were present before and after...l'd be checking harness and ECM for corrosion issues. The P1590 is not 02 related.


​​​​​​​ Brian.

 

I will check if the wire plugs are unseated and also run resistance checks through the cables, Thanks for your input

 

UPDATE:

I ran resistance checks on the o2 sensor connectors, all 3 but 1 showed resistance (upstream passenger side) I pulled it out and it was broken in half, That's what I get for buying ebay sensors. Where should I buy another set of 4 genuine sensors?? There's a ton for sale so please advise which are genuine and where I can get them.

Also I checked every fuse in the fuse box, all but 1 was blown (20 amp yellow F4) now that fuse according to the box cover diagram is for the windshield wiper sprayer but that works fine? I will replace it anyways.

I ran voltage checks while car was powered on (2 key turns) battery is reading 12.46V, and the o2 connectors from the ecu showed 12.3V on all 4 wires, so power IS going to the sensors but they were still throwing inactive codes.

Cleaned all grounds and the ecu ground too, sprayed electrical contact cleaner on all the plugs + Made sure the wires are seated properly

Once I order another set of 4 new sensors what is the proper step by step for installing them? I am concerned that if I install the new ones and clear the codes before I start the engine that the default lean setting will throw black soot onto the new sensors in turn damaging them, When I pulled the new broken one out the tip was completely black, the engine had only ran for one day.

Any advice or tips for what I should do next would be great, Thanks

 

BACK STORY:

My valve covers are definitely leaking, Not crazy leaking but it gets a little oily at the seal after a week of driving. It seems like a long and expensive job so I am putting it off until I have the time to do it myself.
I read somewhere that the air hose leaks and causes a default lean setting so I pulled the air intake and cleaned it out (no cracks or holes) put it back on and made sure its clamped on tight, Cleaned the MAF sensor too while I was at it

I bought the Disco 2 for $700 with 204K miles on it back in June 2018, Lady told me that the CEL was on just because of an o2 sensor and I put it off and ran it all summer with bad o2's until I realized the terrible mpg and that I needed an inspection done.

Cleared the codes, installed 4 new ebay sensors, ran it for a day ..codes came back up and then I decided to post a thread in here.

 

uh yeah.. eBay sensors are a scam, they do bupkis

Buy some good Walkers off of Amazon, $35 each IIRC


Valve covers are easy especially if you don't have SAI (no tubes on the side of the heads)

You will need: 10mm socket, an 8mm 12 point long 1/4" socket, new VC gaskets, a new upper intake gasket, blue threadlocker, and some RTV black. Probably $50 for the entire project.

Start with removing the alternator and AC compressor. Make sure to disconnect the battery before this! Remove the 6 10mm sockets on top of the upper intake, along with the 2 10mm for the coil packs in back of the upper intake.

After removing that, put paper towels into the intake plenum as to not get any debris inside of the engine, clean the gasket mating surfaces on the lower intake plenum and upper intake that you removed.

Remove the four bolts holding each valve cover on. Inspect and clean thoroughly. Put a thin coating of RTV on the valve cover, and place gasket on top. It will keep it in place while installing. Make sure the bolt holes line up, and the brass bolt holes don't fall out when you place the cover onto the head. Also put a thin coating of RTV on the other side of the VC gasket.

Put some thread locker on the bolts. Hand tight with a 1/4 socket, then turn one half turn. These do not require much torque at all. Install the upper intake and new gasket, then alternator, then AC compressor and belts. You don't necessarily have to take the fan off, if it makes it easier for you any auto parts store will rent you the fan clutch tool. It is 36mm, but double check on that.