Oxygen sensor - needs replacing?

[redoubtable]

Hi there,

My car (2003 Seat Ibiza 1.2 Petrol) has failed its MOT for high carbon monoxide emissions after the 2nd fast idle.

I don't have the exact figures, but the car has noticeably been using more petrol recently.

I was planning to get the oil, oil filter and air filter changed, add some additives, take it for a good spin and then get it retested.

But since then it has been hooked up to VAG-COM and returned the following errors:

Address 01: Engine Labels: Redir Fail!
Part No: 03E 906 033 P Component: 1.2l/4V SIMOS3 00HS4729 Coding: 00061 Shop #: WSC 06402 VCID: 2D5AD94BE7194670BA3 VSSZZZ6LZ4R048484 SEZ7Z0C21554072

Faults Found:

16804 - Catalyst System; Bank 1 P0420 - 35-10 - Efficiency Below Threshold - Intermittent

17511 - Oxygen (Lambda) Sensor Heating; B1 S1 P1103 - 35-10 - Performance too Low - Intermittent

Readiness: 0000 0000


So it looks a problem with the oxygen sensor. Can anyone tell me if this means it needs replacing, or might it be possible to mend it? And can anyone advise whether it will definitely needs doing or whether it might be worth just trying changing the filters, etc, first in an attempt to get it through the MOT retest? And if it does need doing, what will it cost?

Many thanks.

 

[RUM4MO]

Okay, my take on this is, your car is failing for emissions - and there is a Cat efficiency fault getting logged as well as a Lambda sensor fault, so, without checking on that code, I'd hope that it is for B1 S1 which is the pre-cat control probe. In which case I think that you should include replacing that probe with a proper either VAG sourced one or an equivalent NTK one (same make as VAG one), then see how things are. You should be replacing spark plugs as well, and maybe try one of these "cat clean up" additives. After that if things are no better it could be a new Cat. I think if you dig deeper you will find that these engines did suffer Cat failure - but what the root cause for the failures was I can't say.

 

[Slimy]

Personally, when my car (not a 1.2 petrol mind) started using more fuel and failed it's emissions, I swapped the o2 sensor and it fixed the problems. So you're pretty much on to something there.

They can be cleaned, but you're only postponing its permanent failure. My local MOT place cleaned mine for £20, but they broke the heater element so it had to be replaced anyway. As for new ones, for an OEM or NTK one you're looking somewhere between £50 and £100.

I doubt anything else will make that much of a difference, unless you're very overdue a service.

 

[markofoo85]

i have a 2000 seat leon 1.4 petrol and it failed its test,
the high idle was 2700 rpm
my lambda reading was 1.07
the CO2 was 0.53 vol%.

does this mean the lambda sensor needs replacing, if so is it a big job and how much roughly would a sensor cost? can you use a 2nd hand sensor? does it need to be plugged into a computer to clear faults? there is a new cat gone into the car and all the filters have been changed recently.

 

[slicecbr]

i have a 2000 seat leon 1.4 petrol and it failed its test,
the high idle was 2700 rpm
my lambda reading was 1.07
the CO2 was 0.53 vol%.

does this mean the lambda sensor needs replacing, if so is it a big job and how much roughly would a sensor cost? can you use a 2nd hand sensor? does it need to be plugged into a computer to clear faults? there is a new cat gone into the car and all the filters have been changed recently.

This link might help..if you need a new front lamba

http://www.seatcupra.net/forums/showthread.php?t=344898

I ended up changing the lamba sensor (front one) myself, took about 40 mins, but if I did it again it would take 10 - theres a certain way to remove it. I bought a NKT lamba (£120ish IIRC) - as said no point buying a cheaper - when I did it was in bits and would need to assemble / crimp etc. My faults cleared a day or two after replacing - been fine since.