Honda Jazz 2004 Engine warning light - Cat bank 1 - efficiency below threshold

[iSolder]

Car Scanner ELM OBD2
DTC report
Selected brand: Honda

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P0420
Raw code: 0420
ECU: 10
Status: Confirmed
OBDII: Catalytic converter system, bank 1 - efficiency below threshold
Honda: Catalyst System Efficiency Below Threshold

Since the CAT was replaced: The warning light comes on each time I drive on the highway but not on side roads. I reset it each time. It doesn't go out by itself.

I'm in Greece and my Greek isn't fluent. The Honda mechanic said something that translates as "scoring". The sensor is very close to the chassis.

Suggestions appreciated!

[iSolder]

I've just spoken with my mechanic and he told me that the Honda mechanic says that this is a problem with genuine Honda replacement cats. The answer is to fit a 35€ right-angle adapter. for the lamda sensor This cuts down the amount of exhaust gas reaching the sensor, effectively recalibrating it!

I've asked him to order one. We shall see.

[ciciban]

I've had the same issue with my 2007 Jazz. After about 100km of driving after clearing the code it comes back. Did the adapter fix your issue? Curious

[fashionphotography]

i had the same problem after i had the cat and sensors replaced here in the UK after it was stolen . after the first long run the engine light came on. same issue came up on the computer the garage cleared it but then it happened again after a motorway journey. my garage said where did i get my fuel .. after i told him he said their fuel was rubbish lol. so i did as he suggested and put 5 rating from another garage. and by itself the light whent out. that was over a year ago and the light hast returned back on. he said it was the new sensor settling in and didnt like the crappy fuel.