Changing O2 sensor

s40volvo · Post by **s40volvo** » 10 Jun 2010, 12:31

Hello,

New to Volvos and recently bought an 05 S40 2.4i.

Looking for instruction on how to change the O2 sensors on my car.

Any help much appreciated.

I have some other repairs that needsto be done

!. Front bearing
2. Muffler and pipe
3. SRS module
4. Possibly steering column

Post by **JDS60R** » 10 Jun 2010, 12:48

Oxygen sensors are of a standard size 22mm (which is very close to 7/8 in) You simply unplug the sensor when it has failed or reached its 100K mile service life and then remove it by placing a proper socket or closed end 22mm wrench on it. Anythingless than the suggested tools may strip the nut used to release the sensor.

Some of the oxy sensors stick or rust on. A few days before removing it is fine to soak the thread area by spraying a penetrant on it where it enters the pipe.

On the day of remove the car should be cool to the touch and you should turnout the sensor.

Your replacement ( a direct fit Bosch is highly suggested - cheapest on Amazon and best to use Matthews link) should come with antisieze on the treads . If not, make sure to apply some to the threads but not the sensor. Your Volvo has at least one sensor before the catalytic converter and one after.

If it gets stuck - write back -we will help - just don't ruin(strip, hit with hammer, use low quality/misfitting sockets) the sensor before writing.

s40volvo · Post by **s40volvo** » 10 Jun 2010, 13:56

Thanks for the quick reply. Will the code reader tell me which one is malfunctioning?

Also where is the sensor found?

Thanks !

Post by **JDS60R** » 10 Jun 2010, 17:58

Depends on the code readers ability to stream the data. You need to be able to interpret it as well. If the sensor does have a hard failure ,like a blown heater circuit or its stuck in one end of the range it will throw a code. If it is slow but in range or not accurate but in range no code will be set. It does not tell you where the sensor is - but it tells you which sensor it is inline from the motor. The you follow the exhaust to the right one and replace.

s40volvo · Post by **s40volvo** » 15 Jun 2010, 11:19

Do you have a picture of where the O2 sensors might be located?

s40volvo · Post by **s40volvo** » 15 Jun 2010, 11:20

JDS60R wrote:Depends on the code readers ability to stream the data. You need to be able to interpret it as well. If the sensor does have a hard failure ,like a blown heater circuit or its stuck in one end of the range it will throw a code. If it is slow but in range or not accurate but in range no code will be set. It does not tell you where the sensor is - but it tells you which sensor it is inline from the motor. The you follow the exhaust to the right one and replace.

The generic scanner gave codes:

P0031 and P0037 which are front and rear O2 sensors low signal .

What does it mean?

camilla1010 · Post by **camilla1010** » 28 Aug 2010, 16:22

Please disregard.....I got it done!! WOO HOO!!
I am having difficulty getting the plug loose. Any suggestions??

norockle · Post by **norockle** » 18 Jan 2016, 12:52

On the '05 2.4T engine, the rear O2 sensor is readily visible from under the car (it is on the passenger-side of the catalytic converter.) The front O2 sensor is on the driver's side of the exhaust pipe and is extremely difficult to see. (As of today's date, I could find no useful illustrations or videos anywhere on the web that show the front sensor for this model year...That should have been a clear warning.) Look for the two foil-wrapped wire harnesses: One runs vertically and is not the one for the O2 sensor. The one that runs horizontally is the one you want. It seemed to me that finding the sensor may be difficult, but that replacement is certainly too difficult for me. Here's why: It is possible to remove the driver's side front tire and reach through to access the sensor, but it is angled towards the front (it is not 90 deg. to the exhaust pipe), leaving a impossible angle for most O2 sensor sockets. You can also reach it from the top, blindly, and even get pretty-good access from the side with the battery and box removed (once you also figure-out how to detach the battery temperature sensor.) Even without the battery and box, however, there is not sufficient space to attach any kind of 1/2 or 3/8 drive socket, flex-joint, or extension and then have sufficient leverage to turn the sensor. And, the greater the number of extensions and flex joints, the greater motion there is with the entire apparatus such that you hardly exert any torque on the sensor before you've run out of swing-room. I'm afraid that after 4 hours of trying everything of which I am capable, I've had to give-up on this one.

It would be a real pleasure to find the design engineer for the exhaust and catalytic converter system at Volvo and have him or her come and do the replacement in normal field conditions. I could expand my Swedish vocabulary beyond normal boundaries of good taste before we then go the dealer together and find-out how it's really done. I suspect they will disassemble the whole driver's side steering mechanism to gain access, but we'll soon see. It's another case of things made relatively easy for the assembly process and nearly impossible to service. The buyers really do pay the price for this kind of manufacture short-cut.