VSC light + red triangle light + VSC off warning lights

[misterarse]

Newby back again, having had engine warning lights on recently & scanner checks indicating CAT underperforming I tried ‘Cataclean’ which worked for 3 days. Before that a tank full of 99 RON petrol seemed to extinguish the little engine warning light for a few days too. Had the engine carbon cleaned for twice the normal time (60 mins) today & the minute I drove away, vibrating steering wheel & new warning lights not seen before (as in title). I have seen comments like "sensors need re-calibrating" to "replacement oxygen sensors" elsewhere which I hope leads to sensors & not CATS as I have been quoted nearly £1200 for OEM parts.

BTW The engine can hardly be heard now, smoother shifting and power delivery, probably quicker too & they claim up to 4 MPG improvement as well so for £100 a good investment despite current situation, especially as mine has done nearly 195,000 miles.

Merry Christmas

[Haylands]

The cats have a pre and post cat lambda, the pre cat lambda tells the engine ECU how the engine is performing, the post cat lambda checks that the cat is working correctly, most faults to do with the cats are down to faulty lambda probes, sounds like one of yours is failing which is not unusual at that sort of mileage. A study of live values with a diagnostic tool should help to diagnose this. I would have thought the garage who did the clean would have checked the before and after emissions..??? did they reveal anything...??

If it does turn out to be the cats, then look for a local place that makes stainless steel exhausts, they can fit a generic lambda for much less that will work and be as good as the original...

VSC is unlikely to have been affected by anything in your post so maybe just coincidence, again, diagnostics should reveal the issue...