Engine Warning Light - P0135 Oxygen Sensor Heater

Engine warning light came on. Have scanned and have a P0135 code with O2 sensor heater identified. I have taken out the sensor from just after the manifold - checked wiring and cleaned it (you never know) and no joy so it looks like a new one needed. But I want to double check this is the right part from the pics:







If anyone has fitted one before can you recommend a supplier - is it worth taking a chance on a used one?

...plus - will driving it do any harm, it runs fine, the error is only happening from cold ignition which runs a bit lumpy - consistent with a faulty O2 sensor heater.

I think it will be running rich if the engine light is on so driving it for great lengths of time may damage the cat.

Let me know how you get on with a new sensor as i have a similar issue, i can't make out if the misfire is causing the O2 sensor fault because of unburnt fuel going into the exhaust or if its a faulty O2 sensor causing the misfire.

I think on my unit it is the heater part of the sensor that has failed. If I clear the error once I've started up it doesn't come back on again while driving, only after the next start up. My guess is that the ECU is detecting a failed circuit in the heater unit as the light comes on immediately. As I understand it the O2 sensor doesn't work properly if cold, but once warmed up will be okay.

As for the part - I'm a bit lost, prices seem to range from £15 to £130. They all look the same to me.

Sensor will work fine, but the pre heater will not.

It will not make it run lean.

Just order a universal 4 wire lambda sensor and use your original plug.

Getting a direct fit one can be pretty hard and costly.

But if you find a supplier then share the word!

Thanks HJ. I've seen a couple around £30 that look like they'll do the job. Having emailed a couple of suppliers I've only had one hit and a quote of £135 for the part .

Follow up to this was that I bought a cheapo on Ebay (17GBP) and it fixed the problem - for a couple of weeks. Then the engine light kept coming and going periodically - always the same error. I had an MOT today and so last week I tried a bottle of Cataclean in the tank, this cleared the light and the emissions test passed but when I went to pick up the van and my new MOT cert the engine light was back on!

Most sensors are good for 100k + and normally an error showing for this is because of another fault elsewhere. I would consider checking the MAP sensor and any vacuum hoses (my favourite). I would put money on it being an air/ fuel issue.

A lot of the cHeap shit sensors on Ebay are just that, cheap shit, I bought a maf for my Merc, same story, sorted for a few weeks, then light back on.

^^^ What the wise scottish git said

Cheapo chinese lambda sensors are pants. Plus they are quite delicate to depending how they are handled will determine its life span.

I tend to buy Denso or Bosch universal sensors from a motor factors for about £50ish.

Check to see if yours works - take sensor out, put 12v to the heater wires and see if it gets hot - measure the resistance of the heater winding - should be somewhere between about 5 and 12 ohms.

Picked up a denso for £43 delivered. The difference was obvious right away - loads of spare length of wire on the sensor, proper heat wrap, crimp connectors, anti seize compound and excellent instructions including alternative wiring combos (although the wiring matched anyway). It also matched the original before I replaced it with the cheap one - a flat end with circular holes around the cylinder not slices and a rounded end.
No more warning light and no rough rumble on start up and running much smoother.