1998 V70R Catalytic Converter

dcmike · Post by **dcmike** » 27 Mar 2018, 11:19

I recently replaced both O2 sensors on my car and I am still getting CEL for bad O2 sensors. Is it time to replace the cat?
If so does anybody sell the down pipe and cat for the car?

Thank you.

Post by **bmdubya1198** » 27 Mar 2018, 12:02

Which codes are you getting, exactly?

I know iPd sells a downpipe with the cat, and I'm pretty sure ViVA sells one too. If you check out some of the Volvo performance parts sites you'll find one. However, I'm not sure if they are for AWD. You'd have to check on that.

Post by **abscate** » 27 Mar 2018, 12:54

Your bad OXS code probably was caused by something else - but they probably needed to be replaced, too.

WhatAmIDoing · Post by **WhatAmIDoing** » 27 Mar 2018, 13:32

The cat will not effect the upstream O2 unless you have a really bad exhaust leak. If both sensors are throwing codes, I would look at the wiring. What sensors did you buy? OEM bosch is recommended. If it's not clogged, the cat is probably fine.

dcmike · Post by **dcmike** » 27 Mar 2018, 13:35

I replaced both sensors with Bosch. I will check the codes again and post them later.

dcmike · Post by **dcmike** » 27 Mar 2018, 13:49

The codes are P0141 and P0136. Also P0455

WhatAmIDoing · Post by **WhatAmIDoing** » 27 Mar 2018, 14:02

First code is for a heater circuit malfunction for the down stream O2 sensor. Second code is low voltage for down stream O2. Fixing one will fix the other. You probably have a short, so time to start tracing a short to the downstream O2. But first try re-seating the after-cat O2 sensor harness. Clean it up really good if there is a lot of crud in the harness. The same codes get thrown if that sensor is unplugged. After re-seating, clear the codes, pray to the Volvo gods, and see if the codes come back. It will take 2 driving cycles to throw the codes for a bad downstream 02 sensor.

Post by **bmdubya1198** » 27 Mar 2018, 14:25

P0455 is a side effect of owning a Volvo... disregard that. It's also worth checking your fuses. My cousin had an issue with a bunch of O2 sensor-related codes coming up and after changing his upstream sensor and a whole lot of troubleshooting, we eventually discovered a blown fuse. Swapped it out and the light turned off instantly.
I can't remember which fuse it was, but it was some kind of emissions fuse, 90% sure it was in the main fuse box.

dcmike · Post by **dcmike** » 27 Mar 2018, 14:34

Thanks for all the input. I will work on the car Friday and let you know what happens.