02 sensor problems!

[Soy2]

Hi guys,

So I have recently replaced my whole exhuast from the downpipe back on my 2014 1.4 polo (CGGB). The Downstream sensor was seized so I replaced it with an NTK sensor (which I heard was the best without paying dealership prices for OEM part). Cleared the codes and after a few cycles bank 1 sensor 1 codes start showing so I assumed it was aged and had to also be replaced. So I did the same with an NTK one.

Cleared the codes and after a few cycles it’s throwing codes for both. I can get specific code numbers if needed.
Any help would be appreciated, it’s been a real pain! Hoping a don’t need to pay the £300-£500 for genuine parts.

Cheers.

[iichel]

NTK certainly isn't a bad brand. are you sure your catalyst itself is still in good condition? Wiring is OK?

[Soy2]

The secondary cat is brand new. And I don’t think sensor 1 would throw this type of code with a bad mani-cat?

I’ve looked a most of the wiring and don’t see anything bad. Also all the fuses under the dash and near the battery are sound.

Im going to clean off all my earths but they all don’t seem too bad at first look

[iichel]

what codes were you having and what codes do you have now? faulty sensor 2 could throw an erorr pointing towards sensor 1.

[Soy2]

Went out and scanned the car now and it says this vehicle has no fault codes! so I’m hoping it’s resolved itself. I’ll rescan tomorrow after my drive to work and update here.

[iichel]

the fault will likely only re-appear after vehice is driven. also pay attention to the status of the fault. active or passive/sporadic/intermittent.

[Le_Combattant]

Each people change 0² sensor by a OEM brand: they have trouble.

Yes, VW parts are expensive: but you avoid issue like that, money trough the window for nothing.