Wisconsin emissions testing failure new downstream 02 sensor does not heat

[1998-S90-Owner]

My 1998 Volvo S90 will not respond to new downstream oxygen sensors. I have tried a Bosc universal and now a Walker specific for my vehicle.

I am not a car mechanic but I have the aptitude to be one. I have been trying to pass Wisconsin emissions testing for 10 weeks more or less.

There is an apparent short in my wiring harness between my downstream oxygen sensor and the power source. I had installed a new, after-market downstream sensor made by Walker complete with an oem connector. It apparently has no power according to the installer. The car throws P0136 and P0141 codes.

Does anyone have the wiring diagram or other insights?

[93Regina]

wiring diagram

Here...large PDF

[1998-S90-Owner]

Thanks for attempting to show me the wiring diagram. It does not open correctly for me. I get an error message that there is no content.

[oragex]

How is the downpipe flexible section? If it leaks it may confuse the 2nd O2 sensor.

[lummert]

Thanks for attempting to show me the wiring diagram. It does not open correctly for me. I get an error message that there is no content.

Try this for wiring diagrams:
www.volvowiringdiagrams.com

[1998-S90-Owner]

Thank you for the wiring diagram url.

I have succeeded in viewing it. It seems to have only one page of the components list, however. That page, displays as page 44 of 260, and starts with "33/1-705" and ends with "D21...(Carphone)." The rest of the manual seems to be there. The order is all jumbled and I have tried paging through it all, so far looking in vain for the rest of the components list.

Does anyone have the missing component list?

The flexible pipe is properly attached on both ends and intact, though it had been loose on the lower end . Thanks for the tip.

I have a new vacuum check valve on the way and have on-hand a new Genuine upstream O2 sensor. The black/white check valve to the smog pump solenoid is shot. I may buy a Genuine downstream sensor, if I can actually get one.

The car has thrown a P0410 code (Secondary Air Injection System) at least 3 times when executing a warm engine start. Each time I had competed a Volvo drive cycle shortly before the hot start. The oddity here is that the smog pump should not run on a warm start. What would cause the error message?

I just got 25 mpg on 250 miles of mostly Interstate driving, on a car that is EPA rated for 23 mpg. Does that sound like a car that is not achieving closed loop?

What OBD tool is the best for the money for the S90? So far I only have a FIXD blue tooth dongle, has limited use.

[1998-S90-Owner]

How is the downpipe flexible section? If it leaks it may confuse the 2nd O2 sensor.

Thanks!

[1998-S90-Owner]

Thanks for attempting to show me the wiring diagram. It does not open correctly for me. I get an error message that there is no content.

Try this for wiring diagrams:
www.volvowiringdiagrams.com

Thanks!