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Chat Area => General Car Chat => Topic started by: Impact Pete on 16 February 2017, 15:16:37

Title: oxy sensor question
Post by: Impact Pete on 16 February 2017, 15:16:37
Hi, my friend has asked me about a fault on his Vauxhall Zafira, he has a light on and had it diagnosed at a garage but all it says on his invoice for the diagnostic is 'number two oxy sensor two codes' I'm assuming this is the lambda sensor and from a google search it's the down stream sensor after the catalytic convertor,
Can anyone confirm this and does the diagnostic make sense? I think he was quoted £100 but maybe that was just for the part as europarts have them at £90 but ebay around £25.
don't want him to waste money if it's just a case of bolting and putting a new one in for him
Title: Re: oxy sensor question
Post by: citroenguy on 16 February 2017, 15:29:59
Lambda sensor, O2 sensor, oxygen sensor , all the same thing  :y
And no 2 is usually after cat sensor.
Title: Re: oxy sensor question
Post by: Impact Pete on 16 February 2017, 15:51:35
Lambda sensor, O2 sensor, oxygen sensor , all the same thing  :y
And no 2 is usually after cat sensor.

great thanks,

would you say it is simple to replace? easy access etc? or do the old ones tend to not want to budge? my only experience is replacing a back box on an exhaust
Title: Re: oxy sensor question
Post by: citroenguy on 16 February 2017, 17:07:10
The rear ones are usually pretty easy to get at. Prepare with lots of penetrating oil and you'll need a deep 6-side 1/2" socket or a special O2-sensor socket.
You can cut the wires off and use the normal deep socket, but first check so that the wires and connectors look ok before doning anything.
Unless the new sensor already has antiseize on it apply a little bit to the threads.

Is it a Zaffy A or B, which engine?
Title: Re: oxy sensor question
Post by: Kevin Wood on 16 February 2017, 17:08:31
Beware of garage mechanic diagnosis. A code related to the oxygen sensor is not necessarily an instruction to replace it. ;)
Title: Re: oxy sensor question
Post by: Impact Pete on 16 February 2017, 19:30:12
The rear ones are usually pretty easy to get at. Prepare with lots of penetrating oil and you'll need a deep 6-side 1/2" socket or a special O2-sensor socket.
You can cut the wires off and use the normal deep socket, but first check so that the wires and connectors look ok before doning anything.
Unless the new sensor already has antiseize on it apply a little bit to the threads.

Is it a Zaffy A or B, which engine?

Its a 2006 1.6
Title: Re: oxy sensor question
Post by: Impact Pete on 16 February 2017, 19:32:54
Beware of garage mechanic diagnosis. A code related to the oxygen sensor is not necessarily an instruction to replace it. ;)

A curve ball!, my mate says it's a bit low on power until he gets to about 50mph but I'm waiting for him to give me a more detailed description of what actually is happening
Title: Re: oxy sensor question
Post by: Impact Pete on 16 February 2017, 21:56:24
Beware of garage mechanic diagnosis. A code related to the oxygen sensor is not necessarily an instruction to replace it. ;)

OK my mate reports the following ;

All I've noticed is the car performance from start, some time it takes a while to pick up the speed specially when driving under 30 mph, but not all the time and the light on the dashboard. I have not noticed any other thing so far.

Any ideas would the sensor do the trick?
Title: Re: oxy sensor question
Post by: Kevin Wood on 16 February 2017, 22:11:57
Beware of garage mechanic diagnosis. A code related to the oxygen sensor is not necessarily an instruction to replace it. ;)

OK my mate reports the following ;

All I've noticed is the car performance from start, some time it takes a while to pick up the speed specially when driving under 30 mph, but not all the time and the light on the dashboard. I have not noticed any other thing so far.

Any ideas would the sensor do the trick?

Hmm. If it was just the post-cat sensor it wouldn't affect running, so I suspect that's not the end of the story.

It would be good to see exactly what codes were present, and perhaps take a look at the live data.
Title: Re: oxy sensor question
Post by: Doctor Gollum on 16 February 2017, 23:53:52
Should pedal trick :y
Title: Re: oxy sensor question
Post by: Impact Pete on 24 April 2017, 22:25:55
ridiculous I know but only got round to plugging in a reader to his car this week, the code shows P0141 and says 02 Sensor Heater Circuit Bank 1 Sensor 2

does this give a better diagnostic?
Title: Re: oxy sensor question
Post by: cam.in.head on 24 April 2017, 22:44:59
that does sound like a sensor or supply problem but can also be simply a bad connection at the plug. if its a standard 4 wire sensor then try unplugging it and measure the resistance across the two white wires.cannot remember the exact reading off my head but if open circuit then it will be obvious.if you have a resistance then try plugging back in to check. reset light and see. it might not come back on immediately anyway even if fault is still there as it requires afew run cycles to self check
Title: Re: oxy sensor question
Post by: TheBoy on 25 April 2017, 08:19:44
As has already been said, the cat efficiency lamda will not impact running in any way, shape or form.

If there is another condition, but no code, you're gonna have to analyse the live data.


If its a tinpot code reader, the actual text might be 'dangle berries', so treat that with a little sceptism (many codes have multiple, but related, meanings)
Title: Re: oxy sensor question
Post by: Marks DTM Calib on 25 April 2017, 09:02:15
Might be worth him popping to Nottingham for a code read and so I can test the coil pack (as that causes low power on these regularly)