How to remove oxygen sensors XC90 T6.

Post by **billofdurham** » 10 Feb 2011, 12:04

I am posting this in response to a PM from member gshadow325.

i was wondering if you can get me the instructions to remove all the oxygen sensors from my 2003 xc90 t6? i am sure its simple to do, but when i do tackle the job...i would hate to get caught with my pants down!

XC90 Heated oxygen sensors replace..pdf: (105.79 KiB) Downloaded 7410 times

Bill.

TJMAS · Post by **TJMAS** » 22 Feb 2011, 06:51

when the directions say "caution not position of probes" is that because the plus are differant for the right and left sensor? Haven't pulled them out yet or gotten the new to see but was wondering.

Post by **jimmy57** » 22 Feb 2011, 10:17

The left and right side leads must be kept in order for front sensors as the connectors are the same. As long as the harness side connectors are left in their holders it isn't a problem.

Post by **gshadow325** » 27 Feb 2011, 08:38

here's another for the maintenance database!

So here's the parts list if you dont want to buy OEM Volvo, I did bosch replacements.

Really straight foward to swap out. They should be done on a COLD car, i move it all of 10feet and running for 3 minutes and it was warm to the touch. Get yourself a Oxygen Sensor removal tool for the two top ones. Makes LIFE ALOT easier, if not you would have to do it the long way and remove the headshield surrounding the turbos (2hr job this way, ask me i know haha). Advice is to remove the sensors one at a time starting from the connector then goto the sensor, this way the wires dont get twisted all up.

I took out the air filter box to get to the two connectors for the front O2 sensors.

stick you hand in and follow the wires down. they clipped onto something on the transmission. pull them off the trans, the new sensors has new clips to put the connectors back onto the transmission. the white plug in the background is the front right sensor. the front left plug is black. they are keyed differently so there will not be any mix up and the rear is only a 4 pin plug.

You can mix up where to install the O2 sensors back in, take note on my 2003 T6 AWD car white is right, black on the left.

For the bottom sensor, i put my car up on ramps since it was time for the 2500 miles synthetic Mobile 1 Oil change

I used a open ended wrench for this one. It was a piece of cake, hardest part was getting enough leverage to get the sucker off, my car does have 152,000 miles

You will need a t15 torx to remove a clamp that holds the sensor wire in place. Expect yours to be rusted on like mine. I cut it off since old one was getting trashed anyways. I used a $0.50 1/2" metal worm clamp to secure it to the exhaust hanger. Though about using a plastic ZIP tie but the potential heat issue kinda threw that idea out the window.

Here are what 152,000 mile O2 sensors look like. They seem pretty good, i really could not tell from the dis-assembly if they were changed before. they looked ok, but then again it might have been changed before. well now i know for sure they have been changed. I also did it in this order, bottom one first(had to change the oil too), then brought the car back down and did the top two sensors.

I changed the sensors in hope of getting better gas mileage. I have been averaging only 16.5mpg on the highway @65mph and 10-13 city. I know for sure though when my AWD was not working i averaged 21mpg coming home from a 350 mile road trip. I dont drive this car like i drive my convertible. I know I do not want to buy a new transmission, so she gets babied...the convertible gets DRIVEN

I will report back after a few tanks of gas to see if there was a change in miles per gallon. another note, it might be all in my head but, it does seem to idle smoother.

Post by **gshadow325** » 28 Feb 2011, 04:50

Well for no apparent reason me and the family took a 200 mile trip to see some relatives yesterday after i posted the info above! LOL, well i knew what i wanted to see. My labor did bear some fruit!

Cliff notes: Changed all O2 sensors,net gain in MPG was ~20%

So earlier in the week i went and did a 200 mile trip and averaged 65mph and got 16.5 MPG per the trusty on board computer. On this last 200 mile trip per the OBC i got 20.4mpg. I never ever saw numbers like this unless my DEM was pulling a DEM 0007 code(hydraulic sensor) and not working i got 22 MPG.

Going by these calculations

16.5mpg x 17 gallon tank = 280.5 miles per tank
20.4 mpg x 17 gallon tank = 346.8 miles per tank
66.3 miles per tank increase !!

thats saving 4 gallons of fuel @ average $3.25 per gallon = $13 per fill up

$325 for the sensors + $0 for labor = $325 cost to replace the sensors

$325 divided by $13 savings per fill up = 25 fill ups to reap the benifits of new sensors or 8750 highways miles or 7.5 months

YMMV, my car has a Yakima Cargo basket with my spare tire up there, so you may net higher gains than me. i am comparing my own findings.

MY vehicle specs @ time of this test:
151,750 for the first MPG test (pre O2 change) 16.5mpg 200 mile trip highway cruise control set for 65mph
152,175 for the second MPG (post O2 change same day, immediately after the installation) 20.4mpg 200 mile trip highway cuise control set for 65mph
No engine codes prior or post test.
AWD working
K and N Filter Panel installed pre and post test
Changed oil from Royal Purple to Mobile 1(old oil had 2500miles on it)
i used 87octane fuel for both mpg test,

Post by **billofdurham** » 28 Feb 2011, 11:53

Good job.

Thank you for the update and good photos. I'm putting this in the Repair Database.

Bill.

dwmoss · Post by **dwmoss** » 21 May 2011, 07:58

Searching for oxygen sensor replacement guides on my 2000 s80 and found this. I know its not the same but thanks for the images and information.

dm

Post by **gshadow325** » 21 May 2011, 19:33

it should be real close...both have the t6 motor aka 2.9l twin turbo 6

joelq · Post by **joelq** » 13 Jun 2011, 13:32

I have to trace a short in the heater circuit on my 2004 XC90 2.5T and need to know the locations of the sensors. Are the locations of the sensors on the 2.5T similar to those on the T6?

Post by **gshadow325** » 15 Jun 2011, 19:30

no, t6 is a 2.9l twin turbo straight 6, you 2.5l car is a single turbo inline 5