Air Quality Sensor needs replacing

sut10 · Post by **sut10** » 21 May 2013, 23:49

An error code scan on my 2004 XC90 2.5T indicated that the air quality sensor wasn't working and hence needs replacing. Can anybody please tell me how to replace the sensor?

Background: The air con started working erractically with the blower speed changing lots for no apparent reason. We noticed the blowers kept running for a while after turning the engine off, (i've read on this forum that this is can be a normal process, however we hadn't really noticed it before). One hot day we are presuming that the blower kept running until the (new) battery went flat. We pulled the fuse on the air con to prevent this happening again and got the error code scan done.
I'm not sure if this issue is related due to the shared control module, but we also have the intermittent radio problem that others report. Sometimes the radio works, other times it doesn't. Sometimes it starts working only to cut out later. When it is working, there seems to be a ~20 second delay when you change a control setting (i.e. preprogrammed channel or volume). I'm planning on replacing the radio system with an aftermarket once we've fixed the air con problem.

Any help with fixing the air quality sensor would be greatly appreciated! Thanks Dave

jetskifast · Post by **jetskifast** » 23 May 2013, 10:34

Majority time XC90 fan motor goes nuts, runs battery down by fan running with key in off position.
Blower motor resistor has gone bad.
Just replaced my blower resistor few weeks ago on my 04 T6 XC90. Not hard job to do yourself.

sut10 · Post by **sut10** » 23 May 2013, 23:15

Thanks for the suggestion, a resistor sounds much cheaper than the sensor to replace. Does anybody know where I can find a step-by-step guide to replace either the resistor or air quality sensor?

Thanks again!

jetskifast · Post by **jetskifast** » 24 May 2013, 08:59

sut10 wrote:Thanks for the suggestion, a resistor sounds much cheaper than the sensor to replace. Does anybody know where I can find a step-by-step guide to replace either the resistor or air quality sensor?

Thanks again!

For fan and resistor replacement go to page two here, see post "Anybody replace blower without removing dash"
You can also use Google.

sut10 · Post by **sut10** » 25 May 2013, 07:38

Great, thanks for that link. If I need to replace the resistors, that's a massive help.

Given the error code did highlight the air quality sensor, if anybody else has tips on how to replace that i would still be keen to hear your advice.

Cheers Dave