2004 XC70 with P0030 code, upstream OXS

[hajjat]

Hi,

First post here! My 04 XC70 2.5t is throwing P0030 code: Heated Oxygen Sensor (HO2S) 1, bank1, heater control - circuit malfunction.

I reset the code multiple times, but it keeps popping up. Replaced OxygenSensor fuse, but problem still present.

I read online that "Circuit Malfunction" could be due to some loose connection rather than a faulty sensor, but I thought I'd check both. So wanted to unclip the sensor connector and clean up the pins.

Noob here Can someone please confirm if this is sensor1 bank1? Taking picture from top, passenger side

I traced down the wire with my hand and it goes all the way to driver side, underneath the air intake and fuse box. It's so hard to get to it, I can't even see it. Any thoughts on best way to reach out to the electrical connector of the sensor so I can unplug it?

Thanks a lot!

[hajjat]

Update: I snuck in my phone to see how the electrical plug of the sensor looks like. Any idea how to unplug it? I tried many times but couldn't (again, I can't see anything, so just using my fingers). Didn't want to use force so it doesn't break. Please help this new noob here

[abscate]

You have the right sensor. We only have one a Bank of cylinders on our Volvo’s so it’s Bank 1

The first sensor before the cat is sensor 1.

You need a small right angle pick. Get that into the hole in the grey release tab and flip that up 90 to release the connector.

[hajjat]

Thanks abscate!

The first sensor before the cat is sensor 1.

Oh didn't know there was another one after the cat too (noob here )! Would the one after the cat throw a different check-engine code/description (say, bank1 sensor2)? Just trying to see if I need to buy both sensors or just the one I posted earlier.

Thanks a lot for the pick tip, didn't notice that hole! Will give it a shot and see!

[abscate]

That right on the second sensor. That sensor just “ monitors “ the cat efficiency so has less to do with good running.

It has a separate set of codes if the sensor or the heater circuit fail.

[hajjat]

UPDATE 03/01/2020:
I replaced the upstream oxygen sensor (shown in pictures above) and it worked like magic! Bought the Bosche one from FCPEuro. The error code disappeared right after installation. Thanks a lot!

[abscate]

That’s probably about a $400 job at the dealer, well done!

[liambean]

That right on the second sensor. That sensor just “ monitors “ the cat efficiency so has less to do with good running.

It has a separate set of codes if the sensor or the heater circuit fail.

Yes, those codes are P0136 for low voltage to O2 sensor bank1 sensor 2, and P0141 for failure of heater circuit for the same sensor.

[hajjat]

Good to know, I hope that code never shows up tho