I've been putting up with the EMS light for about 6 months now and I probably need a new lamda probe. It seems it will cost about £300 for diagnosis, parts and labour. Bit steep, or not?

Before you start buying parts, why don't you find someone with VAG COM or if not just buy a cheap scan tool like the Gendan one - the one for VAG would be the best one, this costs less than £40 (www.gendan.co.uk) and will read and clear any ENGINE, ABS, SRS and AUTO TRANS - its very simple to use and self contained - though you might need to source FOC elsewhere online a full listing of codes. These scan tools, while not allowing as much access to things as VAG COM will probably suit someone that just wants to save money on diagnostics on their own engine and ABS. If I were you, I'd just buy a Lambda probe from VAG as they will sell you the correct one first time - there are universal ones of each type about but you need to graft in part of the original wiring and connector - and that will always be the weak link due to corrosion. Cost in my experience, from £90 > £130 depending on which one - and this worked out roughly the same as buying online - well did for me when I was buying one. As for changing the actual probe - once again in my experience, if you can use a spanner then you are "home and dry". So adding the price of both parts and replacing it youself - you should save £100+ - but first of all get a scan done or a cheap scan tool bought and used before buying parts - oh and unplug check and plug back in the Lambda probe if that is what is being reported as being the problem. If you have two probes "bank1 S1" is the control one - nearest the engine manifold and "bank2 S2" is the down stream monitor probe.

Edited 10 June, 200917 yr by rum4mo

... just buy a cheap scan tool like the Gendan one - the one for VAG would be the best one, this costs less than £40.

The approximate quote I got was from my dealer. I never thought of diagnosing and fixing it myself. Is it a quick and easy job to replace the probe?

IF you only have one probe and IF your dealer has diagnosed that you need that probe replaced and IF you can find where it is, then try replacing it yourself - the old probe will have been fitted using anti-seize grease and the new probe comes with that "fitted", so its a case of finding the probe, following the wire back and unplugging the old wiring, then using an open ended 22mm spanner, unscrew the old probe, fit the new probe, connect up the new wiring - job done. The engine fault light will stay on for maybe 6 or so engine starts. Using the Gendan or VAG COM scan tool to read and clear the logged faults is always a wise move for the future as they will stay logged until cleared. If the open ended spanner does not work then maybe the ring end would fit over the connector (I've forgotten) - but at that age I'd think that the probe should come out easily enough.

Edited 10 June, 200917 yr by rum4mo

One thing though - don't buy the really cheap universal Lambda sensors that just come with bare wires on them that you have to wire in yourself, I find that 9 times out of 10 they don't work.

Even if you can't actually do the job yourself, if you source the Lambda sensor i'm sure a local garage will fit it for you cheaply enough. It's a pretty straight forward job but it's easier if you have a proper Lambda sensor socket to get the old one out.

IF you can find where it is, then try replacing it yourself

I have ordered the Gentan tool, which I think is £40 well spent whatever I choose to do. I don't know where to start looking for the probe(s), but I will find out. I have a 2.0i petrol.

It should be in the exhaust mainfold somewhere - 4 wires going to it with a plug in the loom half way along. The wiring itself is usually covered with a tube of heat shield.

Even if you can't actually do the job yourself, if you source the Lambda sensor i'm sure a local garage will fit it for you cheaply enough. It's a pretty straight forward job but it's easier if you have a proper Lambda sensor socket to get the old one out.

Two reasons that I didn't mention using the proper socket, first if it has a two probe set-up, then the first probe could be on the manifold and so close to the engine head/block that using the proper tool is not possible without taking the manifold off - second reason was that on my wife's 2003MY Polo 1.4SE, the probe came out very easily due in part to the use of anti-seize paste at the engine plant. I'd also think, for a DIYer, if the logged codes condemed the probe AND its tight to come out, then its just a case of chopping the cable off (after unplugging it!) and using a ring spanner or deep socket.

I have ordered the Gentan tool, which I think is £40 well spent whatever I choose to do. I don't know where to start looking for the probe(s), but I will find out. I have a 2.0i petrol.

After finding out what the logged codes are, you should locate and unplug the probe(s) cable and visually look back into the plug (pins) and socket (pins) to see if they are bent or contaminated - spray both with WD-40 and plug/unplug a few times to try to make them clean themselves. Please remember to write ALL the logged codes down for future referance - then clear them before trying to sort anything.

As for finding the probe(s), as said above, they should be obvious - they have a 22mm hexagonal fixing + the heat shielding flexible sleeve and a cable comes away from them - there will be no other things bolted into the exhaust.

Please remember to write ALL the logged codes down for future reference - then clear them before trying to sort anything.

Sod's Law: the light went off yesterday, just before I received the scan tool! Anyway, I know from past experience it will come back on again in a couple of days.

The ECU will log the codes for an number of starts anyway. I know earlier ECU's only saved them for 20 starts but i'm not sure for newer stuff.

The ECU will log the codes for an number of starts anyway. I know earlier ECU's only saved them for 20 starts but i'm not sure for newer stuff.

I got 2 codes, which probably relate to the same fault:

17604: O2 Sensor Heater Circuit,Bank1-Sensor1 Electrical Malfunction

16517: O2 Sensor Circuit - Slow Response (Bank 1 Sensor 1)

This seems to be the one nearest the engine, as rum4mo suggests. I note that the Gendan manual did not have the first code - I had to get it from their website. I would be interested to know what they mean by 'heater circuit'.

These Lambda probes have built in heaters to speed up their response from a cold start - heater failure was the problem with the probe on my wife's Polo. Just like me your first codes were not listed in the booklet, did you make any sense of the CD with maybe more codes - I could not load mine - I've got Vista though! I could find out where I found a good and extensive VAG engine fault codes if you need them. Worse still, after this first "not got code meaning", I scanned a friend's Golf 1.6 - same problem - didn't have that code either, but none of this detracts from the Gendan VAG scan tool's usefulness - it just means that you need to find and print out a full set of VAG engine codes - before you next need them! Finally, even when the exhaust gases end up heating upm the sensor, it seems like your Lambda sensor has become "lazy" - so it still means that it needs replacing.

I've had a look on www.lambdapower.co.uk and they only list one 2.0 engine for Fabia ie AZL and if you put that engine code in, it only shows one sensor - but I've found already that their listing is not complete - but in this case I did just search under the engine code and it only showed this engine as being used on Fabia and Cordoba - so maybe what it is saying is true. One thing, is you are ever in any doubt, just try unplugging the plug for the one you find and go for a short run until some codes are logged - then see if they all relate to "bank 1 S1" . The plug for the rear one could be inside a plastic protective box that is held closed by plastic nuts (I think) on the "floor" of the chassis.

Edited 12 June, 200917 yr by rum4mo

These Lambda probes have built in heaters to speed up their response from a cold start

I guessed as much - although I would have thought this part of the engine heats up quicker than most.

did you make any sense of the CD with maybe more codes

I just copied the manual off the CD. I guessed the installation was for the more comprehensive scanners. One can get 3 codes free per week from the Gendan site. I doubt if I will need more - but I could always make up a new email address and register again!

it seems like your Lambda sensor has become "lazy" - so it still means that it needs replacing.

Me too - I have become lazy. It has been like this for six months!