Lambda ageing test

[Psion]

Hi All

I hope i have put this in the right place, my daughters VW Polo AZQ engine is throwing various Bank 1 sensor 1 errors such as

16804 Catalyst system bank 1 efficiency below threshold

16514 oxygen sensor bank 1 sensor 1 malfunction in circuit

I have full VCDS and can run the test on the Bank 2 sensor but I have tried several times to run it it on the problematic bank 1 sensor i hit the brake and throttle simultaneously and the rpm settles around the 2000 rpm mark the the test just will not run. I have checked that the sensor has power is there anything else i can do to ensure this sensor is kaput before shelling out for a new one.

thanks

[Crasher]

It is B1S2 (Bank 1 sensor 2) you have been able to test, if it was Bank 2 it would mean it is a V engine. If the test for B1S1 won't initiate then it is likely the pre cat lambda sensor is faulty BUT on the Polo 9N we often see problems with the wiring and pins at the gearbox mounted plug for the Lambda sensor. Typically these sensors have a life span of around 75k, they are almost considered a service item. Only fit genuine VAG or Bosch/NTK (NGK) sensors as oppropriate for the engine, the ECU is very precisely mapped to match the responses of the particular brand and often misbehave when fitted with a different make.

[Psion]

Hi

thanks for info, I will have a good look at the wiring at the weekend.

A Polo with a v8 in it, now there's a thought :-)

[Psion]

I have had a look at the wring and all looks fine, I have also just had a look at the measuring blocks on VCDS and have noticed one glaring difference between sensor 2 which is fine and sensor 1. Which is under control sensor 1 has no resistance the box is completely empty not even a zero! Would you suppose this is the problem or which wire do I need to check for continuity to the ECU?

[Crasher]

Which measuring block value and field was this in, 041 and 03?

[Psion]

A picture paints a thousand words

VCDS Polo.jpg

Sorry the picture is small but had to reduce it to get the size down

[Crasher]

get the engine hot, go into basic Settings 04, group 034 and click go. Press and hold the brake pedal and then the accelerator fully down and wait whilst the ECU sets the rpm where it needs it and stay like this whilst watching as the cat temp exceeds 400 degrees and then zone 4 should go from "test off" to "test on", wait (it could take a few minutes) until zone 4 says OK or not OK.

[Psion]

Hi

Thanks for your continued help and I have just tried the above and the same result will not go in to test mode, I held the brake and throttle fully down for 10 minutes and nothing. I tried the same test on sensor two and the test run and passed no problem within about 2 minutes of running the test.

Whilst running the test on sensor 1 I noticed that the 3rd box (Dynamic Factor Sensor 1) never moved, it stayed at 0.00 the entire 10 minutes.

[Crasher]

New sensor then.

[Psion]

I was afraid you would say that, as a matter of interest the blank field above on the measuring blocks I posted is there any significance to it just so I can put it in the knowledge bank?