Bought the car a week ago and today the check engine light came on. Plugged in my code reader and it gave me this fault:

P0135 - O2 Sensor Heater Circuit Bank 1 Sensor 1.

I'm not mechanical at all so anyone who can offer advice on what this means and maybe the price range to fix would be greatly appreciated.

Thanks.

Open bonnet lid, peer down, stand immediately in front of engine bay. You will see black plastic engine cover. Follow this towards the front of the car and it leads to the engine exhaust manifold. There will an 02 sensor (lambda sensor) screwed into this. Check to see if the wiring is ok.

If it's all ok, then replacement is required. You will find fuel economy is poor with a non functioning 02 sensor.

PoloD.

Open bonnet lid, peer down, stand immediately in front of engine bay. You will see black plastic engine cover. Follow this towards the front of the car and it leads to the engine exhaust manifold. There will an 02 sensor (lambda sensor) screwed into this. Check to see if the wiring is ok.

If it's all ok, then replacement is required. You will find fuel economy is poor with a non functioning 02 sensor.

PoloD.

Thank you for the help. I've had a look and I can't spot any obvious problems with the wiring.

So if I go for a replacement I've had a look on eurocarparts and it looks to be about £60-£70 for a lambda sensor, however I've seen someone recommend this on ebay:

4 WIRE LAMBDA OXYGEN O2 SENSOR UNIVERSAL VOLKSWAGEN POLO 1.0 1.3 1.4 1.6 -LSU4

http://bit.ly/19vlrkG

Any idea if that would work on mine?

Sadly there aren't many aftermarket variations of these sensors, so you will have to shell out for a new one.

The 4 wire ones are for the earlier polos, or the rear sensor on your car (bank 1 sensor 2)

Have you checked to battery condition ? As low power will lead to these errors. Also worth having the earth points cleaned. A bad earth connection will have the same effect.

Also, these sensors act differently to the normal type as they are a wideband sensor and this has some control over the idle and general running of the engine. Stupid things if you ask me

Go for a reliable brand from ECP. Remember there is a forum discount too.

The fault codes will need to be cleared post change.

They can be difficult to release from the exhaust manifold as they become welded in from the high heat conditions.

PoloD.

eBay sensor looks alright too. Might need some head scratching and terminals to wire up to the original loom.

PoloD.

I've discovered a bloke round the corner from me who is a VW Technician and does work from home in the evenings so just dropped it with him, so waiting to hear back if there's a loose connection somewhere or if it does need a new part.

I've had a look at ECP PoloD and they've got a Bosch one in stock near me I could go and get tomorrow but it's £70 and the club polo 25% discount doesn't work unfortunately. I've had a look on ebay and discovered this which as far as I can tell comes from the exact same model as mine for only £20 - http://www.ebay.co.uk/itm/221314122445?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

In regard to clearing the fault codes is that done easily enough with a fault code reader, or is it more complicated than that?

Cheers again for the help gents.

Ok I've just spoke to him and a) the part needs changing and b) that ebay one is a 4 pin and I need a 6 pin so the £70 Bosch one from ECP will be on my shopping list tomorrow morning.

I might see if they'll do anything regarding the 25% club polo discount but I doubt it???

Yes. Fault code reader will clear.

Does your mechanic friend have a trade card? In any case a Bosch part is good quality and should last. In my books, put a good part in and then forget about it.

PoloD.

Bosch part now in and touch wood no engine check has returned thus far. Have been told that one of the cylinders has a slight misfire though so will need to keep an eye on that.

Thanks for the help PoloD/dixy.

For the slight misfire check

1. Condition of number one spark plug (and the rest too). No 1 is often affected if you have a small oil leak from the rocker cover on that side (very common).

2. Check the ignition lead set for splits or breaks or arcing

3. Remove the black plastic engine cover and look for a split vacuum hose. I had a slight misfire and it turned out to be this. It's a very cheeky hose and a little tricky to find. I posted some photos about this a few months ago. £5 later and some silicone vacuum hose from eBay and fixed.

PoloD.