Hi Guys, 

 

I have a 2004 fabia 1.2 htp azq. Recently the EPC light is on again and after scanning i found the following interesting things

17511 - Oxygen (Lambda) Sensor Heating; B1 S1: Performance too Low

       P1103 - 35 -10 Intermittent

16555 - Fuel Trim; Bank1 : System Too Lean

       P0171 - 35 -10 Intermittent

 

These two error codes was found last winter and after i clear them, the don't come back. So i didn't pay attention. It seems this time the ECU decided to throw EPC light  to alert me again, probably because the sensor's performance is getting worse.

Should I replace the Sensor 1?After searching around, Found that the sensor 1 is on top of the engine, so replacing by myself should be easy. Today i confirm the location of the sensor but i cannot find the plug of it. Does anyone of you can help me to point out the location of the sensor's plug?

You can find the picture of the engine as below:

https://onedrive.live.com/redir?resid=F0B1DDAC62C5DD53!11714&authkey=!AAivlK6Hcq_Av-k&v=3&ithint=photo%2cjpg

 

BTW, it's nice if you can recommend me a seller for the sensor. On ebay, there are some very cheap ones only for about 30 euro. are they trustable?

Edited 9 March, 201610 yr by crazybeeliuzhe

If you are convinced that the sensor is faulty, then I'd suggest only replacing it with either a VAG one or a NTK one which will be same as VAG one but not in a VAG box, find out which is cheapest to get to your door.  I found, years ago, that my main dealer price was okay, also when you get the new one, from the length of the supplied cable, you can work out where the mating connector is.  You should buy or borrow a Lambda sensor socket that allows the socket to locate fully over the sensor while allowing the cable to stay not damaged.

 

Edit:- in my case, I was replacing one on my wife's Polo with the 1.4 BBY engine - the sensor is hidden underneath the manicat which meant I wasted my money on that special socket - ended up using two shortened open ended spanners! You are lucky as the sensor can be reached from above in that engine!

Edited 9 March, 201610 yr by rum4mo

I think this (pink star) might be the connector (mounted on bracket on front of gearbox, viewed looking up from under front bumper, with splashguard removed).

 

 

I seem to remember that the rusty bracket which it slots into made removal a little difficult.

Removing the sensor on ours took a fair amount of effort, but I did it cold, and I think it would have been much easier warmer.

Edited 9 March, 201610 yr by Wino

If you're replacing the sensor anyway then you can just cut the cable off flush then use a proper deep hex socket to get it out and put the new one back in with a spanner, they don't need to be very tight to seal. The plug will be on the other end of the cable, just follow the cable to the plug.

 

Edit: As wino says, remove the old one when the manifold is nice and hot after a run.

Edited 9 March, 201610 yr by sepulchrave

If you're replacing the sensor anyway then you can just cut the cable off flush then use a proper deep hex socket to get it out and put the new one back in with a spanner, they don't need to be very tight to seal. The plug will be on the other end of the cable, just follow the cable to the plug.

 

Edit: As wino says, remove the old one when the manifold is nice and hot after a run.

Thanks a lot guys. I will try it when the tools arrive. 

Thanks a lot guys. I will try it when the tools arrive. 

BTW, it's very weird that the sensor heating is not working properly. The sensor is only supposed to be changed after 150000 km according to the workshop book I found online while my mileage is only 80000km by now. 

BTW, it's very weird that the sensor heating is not working properly. The sensor is only supposed to be changed after 150000 km according to the workshop book I found online while my mileage is only 80000km by now. 

 

The sensor heating element, the catalyst and the sensor itself can be fouled by oil consumption or a lot of short trips, Low mileage cars are more likely to suffer fouling than high mileage cars, using a car as a shopping trolley is the absolute worst thing for the engine, cars which have spent most of their lives in top gear on motorways covering high mileages are generally in much better mechanical condition. Mileage is a very bad indicator of mechanical condition.

The sensor heating element, the catalyst and the sensor itself can be fouled by oil consumption or a lot of short trips, Low mileage cars are more likely to suffer fouling than high mileage cars, using a car as a shopping trolley is the absolute worst thing for the engine, cars which have spent most of their lives in top gear on motorways covering high mileages are generally in much better mechanical condition. Mileage is a very bad indicator of mechanical condition.

Thanks for the explanation. I also agree with you that mileage is not a good indicator.I didn't know it when bought this car two years ago,  I only knew this recently. I think for our next one, i won't be "fooled" by low mileage anymore.

I had to replace mine on my Octavia a month ago. Car on 66k miles. Didn't see a point in clearing fault and waiting for it to come back

Sent from my SM-G900F using Tapatalk

I had to replace mine on my Octavia a month ago. Car on 66k miles. Didn't see a point in clearing fault and waiting for it to come back

Sent from my SM-G900F using Tapatalk

 

Well, sometimes faults take a while to return, though in my limited experience, once a Lambda sensor has given a warning like this, it is time to organise getting a replacement ready.

 

I suggested using a special socket to avoid the maybe "not too handy with tools" owner fighting with getting the heat shield off - though as someone said, maybe these "top mounted" Lambda sensors suffer more from water causing corrosion than the "bottom mounted" one that I replaced, working from postings on VAG forums, I prepared for a horrible job, only to find that the sensor was quite easy to remove, it was the original sensor - car owned from new, but had covered maybe 75K in 8 or 9 years (guessing miles and age).