Oxygen sensor?

[Choongmu]

Hi all,

Does anyone know how many o2 sensors the mk1 vrs has, where they're located and how much they are to replace. My cars running like an asthmatic ant with heavy shopping and when ive fault code read it, i get o2 sensor malfunction bank 2 (or something like that as i erased the code!).

Any ideas?

[RobClubley]

There are two. One before and one after the CAT. The front is a wideband one, about 50quid I think, and rear is a narrowband which is more like 35-40 quid.

Prices are from my addled memory so may not be accurate

[VandrosdisTech]

As mentioned above there are two, one broadband and one planar. They work together in a closed loop system once the engine has reached a certian temp.

Don't just assume the fault code you read is the part that needs replacing, the ECU likes to blame things for irregular readings, and that 20v engine can have other faults which throw up lambda sensor fault codes.

Get it checked by someone with half a clue and you could save yourself a few quid, as it is very rare for two lambda probes to pack up.

The fault you are experiencing may not be responsible for that fault code, it may have been an old code generated and not put the light on. As them engines are getting on a bit in age now, lots of vital vaccuum hoses and intake pipes are perishing and splitting, throwing all sorts of incorrect readings the ECU's way. The ECU recognises it is having to throw in more fuel, and its long and short term adaptive mixture values slowly get worse until the ECU thinks a lambda probe is at fault for not adjusting it correctly.

Also them engine are heavily reliant on correct fuel pressure, again, incorrect readings and values can throw up lambda faults.

Any questions, just ask.

Edited 14 April, 2011 by VandrosdisTech

[Choongmu]

Cheers for the help guys.

It did throw up the good ol 17705 and 17545 codes at the same time so i guess its out with the inspection lamp and look for someone with vagcom!

[TissMe]

Yes , the first Lambda works with the MAF to alter the fuelling

If the MAF has failed or the first Lambda , the second one is the Oxygen sensor

That sniffs the air fuel mixture as it is coming out

It the air , fuel mixture is wrong , the the oxygen sensor will bring on the light and then try to put the balme on the first lamda

But this is just picking up on the fact that the engine is over/under fuelling

It needs to be sorted really , as if it carries on too long , it can kill off the cat (expensive)

As has been said , get it checked out , as even the CTS can affect the air/fuel mixture

To be fair , when my son bought his MK4 Golf , I bought him a CTS as a pressie , as they are so common

But get everything checked

there are a couple of hoses that are common to fail too , so a good garage that have a good knowledge of VAG should be able to help you out

Good luck

Sarah

[Choongmu]

Happened again today, 17707 17745 and 16514 ( i think, but it was bank 1 o2 sensor), was running a bit rough, reset it and light hasnt come on again. Whats this CTS (sorry if thats a thick Q).

Gonna get under the bonnet tomorrow and check all the hoses before getting it to a garage.

[TissMe]

Happened again today, 17707 17745 and 16514 ( i think, but it was bank 1 o2 sensor), was running a bit rough, reset it and light hasnt come on again. Whats this CTS (sorry if thats a thick Q).

Gonna get under the bonnet tomorrow and check all the hoses before getting it to a garage.

Hi

Sorry , CTS = Coolant Temp Sensor

The origional ones are black , as they are common to fail , they supercceded them to a green one

So check that out too , not expensive and if you have a green one to start with , just replace it anyway

Sarah

[Choongmu]

Right first things first. Where do I find this breather pipe that always fails. Took the engine cover off and the bit by the dipstick. But it's just pipes everywhere. Is it easy to get too and which other ones should I look out for.

Where's the cts located too.

Cheers in advance.

[TissMe]

Right first things first. Where do I find this breather pipe that always fails. Took the engine cover off and the bit by the dipstick. But it's just pipes everywhere. Is it easy to get too and which other ones should I look out for.

Where's the cts located too.

Cheers in advance.

http://briskoda.net/forums/topic/54167-splutter-is-doing-my-head-in/

There is one lin k that could help

Just do a search for CTS Coolant Temp Sensor , there is guides on here to help you

Sarah