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Discussion Starter #1
Hello all,
The engine light came on a few months ago, then went off a few days later. It was the above fault code. It came on again yesterday, was the same code and after I cleared the code today the light didn't come back on.
Has anyone else had this? I gather it's the lambda sensor underneath, after the cat, not the one on the manifold. I'm not sure whether as it seems to be intermittent, whether it's the wiring, or whether the sensor is on the way out rather than totally failed at the moment, and whether I should leave it for now, or just buy a new sensor and get a garage to fit it, rather than wait for it to fail completely and the engine runs rough with high fuel consumption, etc. When it comes on at the moment, the engine runs fine.
Any thoughts anyone please.
 

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Bank 1 sensor 2 is only there for monitoring your emissions post cat, it doesn't effect the way the engine runs, but you will fail an MOT with the light on so worth getting replaced.
 

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Discussion Starter #5
I went to a mechanic yesterday. He seemed to think it was unlikely to be failed lambda sensor (102,000 miles) but something else was making it throw an error code, perhaps incorrect fuel mixture, faulty other lambda sensor, cat starting to break up, and suggested doing a full diagnostics to identify the problem. Hmm, doesn't seem right to me, apart from cat possibly starting to fail.
So, would the sensor throw the code if it sensed the cats emission wasn't correct, or if itself was faulty and starting to fail, or either of those?
I gather the sensor is expensive so don't really want to buy one and have it fitted if it turns out not to be that! I gather an emissions test would show whether the cat was not working properly.
As I originally said, when I clear the code it doesn't go on again straight away, perhaps once a day, and didn't go on yesterday.
Anyone else had this problem?
Oh, and the mechanic suggested I fill up on high octane fuel and take it for a good motorway drive. Any thoughts please?
 

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High octane fuel isn't going to fix an issue with the lambda, or any issues really! 8 times out of 10 its going to be the sensor failing, the other 2 it's normally the wiring has got hot near the sensor and has failed. If the cat was bad I would expect a code like P0420, but not always. If the garage was diagnosing the issue, the first thing they should have done was stick the probe up and test your emissions to rule out the cat or primarly , takes about 1 min.
 

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Discussion Starter #7
Thank you very much Ayresyy. I'm sure you are correct. Have you seen this problem on your own or other peoples Astra's and fixed it by replacing the sensor? You're clearly very knowledgable about these cars, are you an enthusiastic amateur with a lot of experience working on them, or mechanic or even perhaps a Vauxhall trained mechanic? :)
 

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I have seen it on a few different cars. Worth getting your emissions checked (literally a 5 min job) just to rule an issue with the CAT or primary lambda sensor (or even AFM), but if that all checks out within spec and the wring is all OK, my money would be on the sensor at fault.
 

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Discussion Starter #9
A vauxhall indie has said the same as previous mechanic, that it could well be the sensor, but 02 sensor trouble codes can be the result of many faults, and want me to pay £45 plus VAT for full diagnostic on the fuel trimming side to give an accurate diagnosis. (Previous mechanic wanted £25 total but he's alone with no large overheads so cheaper).
I tend to agree with Ayresyy, as car doesn't run rough at all, and if it was something else like faulty cat or primary 02 sensor it would surely throw other codes. But then if I got a new sensor and had someone fit it, and the problem persisted I'd be so annoyed! But then if I paid for this diagnosis and it turned out to be the sensor I'd be equally annoyed!!!
 

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Discussion Starter #10
UPDATE I've been checking the freeze frame data when the engine light comes on. It's showing the lambda sensor is producing a voltage of 0.445 v on average when it's throwing the code which sounds pretty healthy to me. So does this mean the sensor is okay? I dunno! I would have thought if it was dodgy wiring, connector or failed sensor would produce 0 volts. ???
 
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