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Catalytic Converter and O2 Sensor Faults

Hey Guys,

I bought my 2008 Suzuki Swift Sport about 2 months ago and genuinely love it.

However I've been having some issues, and was wondering if you guys could help me answer some questions as the repair bills are starting to rack up.

- Throttle not always as 100% responsive as it could be, would have to let off and try again
- Poor fuel economy (Probably get around 25 mpg at the moment..)
- Engine light shortly after. OBD codes were P0172 System Too Rich Bank 1, P0420 Catalytic Converter below system efficiency threshold

I had it checked out, they also found P0134 No O2 Activity Bank 1 error code and I had the O2 sensor replaced, they noted it could have damaged the cat.

All the symptoms are still present but the P0134 code has gone, O2 Sensor 1 and 2 have the same values so believe they are now operating correctly. I'm having the bank 1 cat inspected and replaced in a few weeks.

How many catalytic converters does the Suzuki swift sport 2008 have? I'm guessing two since it has 2 exhaust pipes but I just want to be sure and I don't have a jack or anything to try and look myself.

Has any one else had similar issues? The throttle concerns me a little as sometimes it's nippy as anything, other times I'll try and it'll creep up to speed, and retrying seems to fix it.

Thanks guys, really appreciate the help!

Had to replace my sensor a while ago due to a P0420 fault but it didn't fix the problem. Emissions etc all good so I just keep knocking it off when it comes up again using a bluetooth OBD2 reader. Will pop up every 60-200 miles. Been doing it for over a year now and it's fine. Even when it's on nothing is affected really.

Throttle is also really sensitive and responsive. Weird issue. Can't help much but wondered if you made any progress with it?

Yeah, so I finally got it sorted, quite a mission though. The downstream O2 sensor was failing, it got replaced but it didn't resolve the issue as the new part was actually faulty - Took a couple different visits to garages for them to diagnose this.

Couple that with the same issue a few people have had with the PO420 code and it was very confusing to pin point what issue was. Yeah, emissions were all fine on mine too, my fix is the exact same.

The unreliable throttle was just due to a rich fuel mixture - symptom of the failing O2 Sensor

Glad you got it sorted, you encountered a common issue with the SSS from that generation. Some garages immediately offer a cat replacement which in most cases is not needed at all. FYI, the zc31s has 2 cats, a 400 cel in the header and a 100 cell at the beginning of the mid pipe. Removing the midpipe one doesn’t affect emissions enough to fail MOT’s.