Mostly its simply means you need to clean the cat.
This happend with my Mira ,engine check light turns on and off.
Gets the convertor cleaned and its solved my problem.
If there is any problem with sensor then the check light will turn on permanently.
Noadays insted of improving petrol quantity to increase RON Pakistani cheap companis started adding too much magnesium bassed additive in petrol .Which blocks the converter very soon.
Previously i need to get my cars cat cleaned after every 60-70thousand Kms. This year i needed to get my cars converter cleand after just 20thousand Kms and this time it was full of rusty dust simply cannot describe how much dut was there in it.
These companies are destroying pakistani peoples hard earnd money cars engine.