How to change post-cat O2 sensor

Started by Rockingdad, December 9, 2015, 19:37

0 Members and 1 Guest are viewing this topic.

Rockingdad

Well the sun shined for once this week so as the new O2 sensor and socket had arrived I thought I'd give it a go at changing it. The engine check light came on about thirty miles into owning it (typical!), so after fault coding it as P0140 found out via the forum that it was the sensor just after the cat. Get ready for a mini how to!!!! ( and be gentle, its my first).

I ordered the direct replacement Denso sensor from Opies Oils for £56. I was pleasantly surprised to find that not only was it a direct fit, but it also had all the new clips ready to reclip into the bodywork (you have to cut the old ones to get the old sensor out), and the thread was pre coated with anti seize compound! You will need a 22mm O2 sensor socket to remove the old and fit the new. I got a sealey one for £7 on ebay  s:) :) s:)



If you look underneath the rear of the car following the tailpipe back to the catalytic converter, you'll see the sensor sticking out at a right angle with the cable coming off to the left (passenger side). The pic shows the new sensor fitted as I forgot to take one with the original In.



This is the sensor looking from the top of the engine bay:



The worst part of this job was to get the old one out, it was a bit of a git. good old WD40 or the like will help although I'd run out so I ran the car for a bit to heat the cat which helped get it out. But before you do, Save some swearing and remove the rear passenger light cluster. Take out the two screws shown below



There is a locating point at the bottom of the corner of the light cluster so as you go to remove remember that you need to just move the top fixings out of their mounts after the screws are removed and the withdraw to the right to free it from the locator. the pic below shows the locator once the cluster is removed. There is plenty of cable to put the light out of the way without unplugging the connnectors:



Unclip the connector (squeeze the left hand side of it to release the locking tab) and then follow the connector down, there are two cable ties on the crash bar you can see and another underneath that need to be cut to free the old cable. If you don't have the Denso sensor I bought it may not have the new cable connectors on it so have a think about how you are going to secure the cable. If you have bought the direct replacement, pull the old ties out as the new ones need to clip in there:



Screw the new sensor in, clip the cable clips already fixed to the cable into position, reconnect the plug, refit the light cluster and you're good to go.....

But YOU'RE NOT!!

Don't forget to clear the engine management fault with your OBD2 module otherwise the management will think the sensor is still faulty!

hope that makes sense!
2005 1E7 Silver with some mods.
MR2 How to vids and other cool content here:
www.youtube.com/Daddiaries

Swan_Connery

#1
Good write up mate. Fair to say you're doing a good job so far, enjoy the driving.

Rockingdad

#2
Cheers  s:) :) s:)
2005 1E7 Silver with some mods.
MR2 How to vids and other cool content here:
www.youtube.com/Daddiaries

delhusband

Cheers for the guide 🙂 mine being a git too. Any idea what the recommended torque value for tightening the new sensor to is?
Hate pointy animals

Carolyn

It's pretty obvious when you've got it tight.  It's a short thread and tightens quickly.

The old one can have its lead cut off and a plumber's torch applied to the boss it sits in.  It will come out a lot easier that way.
Perry Byrnes Memorial Award 2016, 2018.  Love this club. 
https://www.mr2roc.org/forum/index.php?topic=63866.0

Tags: