Lambda Oxygen Sensor fails after months

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king464
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Lambda Oxygen Sensor fails after months

Post by king464 »

Hey guys and girls!

First post here but I’ve been looking through these forums for a couple months now and they’ve been so useful! Absolutely love my Polo 6N2, my first car and I couldn’t be happier!

But I do have one reoccurring problem which is really starting to annoy me. I keep getting a check engine light come on, and after scanning the ECU I get the following code:

P0134 - O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

Got my local mechanic to replace the lambda sensor. Car worked perfect for a couple weeks until I got another P0134. He said that the part was faulty (its a genuine Bosch part cost me £130) and he replaced it. Now a couple months later I’m getting the P0134 error again and the lambda sensor is not working (poor economy, poor performance).

I thought originally it could be wiring related but since the new sensor worked for a couple months I thought it must be the sensor. I don’t know what to do and I doubt my mechanic is going to replace the part again (he always wants the car in for ‘diagnostics’ and basically hates my pride and joy).

Side note: recently under hard acceleration every now and again cylinder 3 will misfire (assume I need to fit new spark plugs in). Could this in anyway cause the lambda to fail?

Really annoying that the car is currently slower than usual and burning a lot more fuel (passengers always complain of fuel smell)

Thank you so much for reading!
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alexperkins
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Re: Lambda Oxygen Sensor fails after months

Post by alexperkins »

Overfuelling can kill the lambda over time

I would check the wiring on the front of the gearbox (6 inches back from the plug too) as this has a habit of degrading over time and becoming very brittle due to the heat near the manifold. It often needs to be cut out and replaced with new wiring
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937carrera
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Re: Lambda Oxygen Sensor fails after months

Post by 937carrera »

alexperkins wrote: Tue Nov 06, 2018 6:17 pm
I would check the wiring on the front of the gearbox (6 inches back from the plug too) as this has a habit of degrading over time and becoming very brittle due to the heat near the manifold. It often needs to be cut out and replaced with new wiring
So very true.

There is a diagnostic process using software that test the operation of the cats and lambda sensors, so it is true the garage will need the car to carry out further diagnostic tests. Went through the same myself using VAG-com and eventually found out the brittle wires were the problem
king464
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Re: Lambda Oxygen Sensor fails after months

Post by king464 »

alexperkins wrote: Tue Nov 06, 2018 6:17 pm Overfuelling can kill the lambda over time

I would check the wiring on the front of the gearbox (6 inches back from the plug too) as this has a habit of degrading over time and becoming very brittle due to the heat near the manifold. It often needs to be cut out and replaced with new wiring
This sounds promising as to fixing my problem. But if the wires have become brittle and degraded - wouldn't the new replacement sensors have failed straight away and not work for a couple of months afterwards? This is what is confusing me so much because surely if the wiring was bad then the new sensors wouldn't work at all.
king464
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Re: Lambda Oxygen Sensor fails after months

Post by king464 »

937carrera wrote: Tue Nov 06, 2018 7:58 pm
alexperkins wrote: Tue Nov 06, 2018 6:17 pm
I would check the wiring on the front of the gearbox (6 inches back from the plug too) as this has a habit of degrading over time and becoming very brittle due to the heat near the manifold. It often needs to be cut out and replaced with new wiring
So very true.

There is a diagnostic process using software that test the operation of the cats and lambda sensors, so it is true the garage will need the car to carry out further diagnostic tests. Went through the same myself using VAG-com and eventually found out the brittle wires were the problem
Would you happen to know the specific test? My local mechanic hates my car, doubt he will have the specialist VW software to test for this so may have to find a VW specialist near me... Unless this is something I can do myself with VAG com?
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937carrera
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Re: Lambda Oxygen Sensor fails after months

Post by 937carrera »

http://www.ross-tech.com/vag-com/m_blocks/index.html

Measuring blocks 30 to about 42 I think

From memory the test involves using the brake pedal as a switch to activate the tests, you can watch the lambda value and cat temperature. It's a few years ago for me now.
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