9N3 GTI Downpipe and Lambda Sensors

[PoloGIT]

Hi all,

VAG-COM tells me the CEL I have is due to error "16414 - Oxygen (Lambda) Sensor B1 S1: Heating Circuit: Malfunction (Open Circuit?) P0030" which from what I've read here and elsewhere is the pre-cat sensor. Before I race off and order one, I just wanted to check that a decat downpipe needs/uses both pre and post cat sensors, as I am considering getting one sometime soon. If only one of the sensors is required, which one is it? Also, if one of the sensors is indeed redundant with a decat, does it need to be written out with a phase 1 / 2 tune or something?

Thanks in advance!

[h100vw]

Hi all,

VAG-COM tells me the CEL I have is due to error "16414 - Oxygen (Lambda) Sensor B1 S1: Heating Circuit: Malfunction (Open Circuit?) P0030" which from what I've read here and elsewhere is the pre-cat sensor. Before I race off and order one, I just wanted to check that a decat downpipe needs/uses both pre and post cat sensors, as I am considering getting one sometime soon. If only one of the sensors is required, which one is it? Also, if one of the sensors is indeed redundant with a decat, does it need to be written out with a phase 1 / 2 tune or something?

Thanks in advance!

The fault code for cat efficiency is written out in our Phase 2 tune.

You need both sensors regardless and the front one is the more critical for running.

Gavin

[seangti]

B1 S1 is the front way as per the research you've done. I've recently replaced the post cat, S2 sensor.

[sambb]

So Gav, the A:F system still actually needs/uses both the pre and post cat sensors - its just that the cat flow error that the second sensor can generate is ignored. Is that right?

[h100vw]

So Gav, the A:F system still actually needs/uses both the pre and post cat sensors - its just that the cat flow error that the second sensor can generate is ignored. Is that right?

I am going on what Kev in the UK has told me. The tune is written to not switch on the CEL, if you look with VCDS the fault is there.

He said, when I asked that it needs to be fitted and working.

Gavin

[sambb]

I'm running a second 02 sensor spacer to avoid the CEL, but I wonder if standing the sensor off like it is could affect mixtures. On the run my car is doing low 12's (AFR that is!) which is ok, but at idle it smells rich since I got the dump/cat/spacer put on. Ever heard of a spacer causing that kind of thing?

[h100vw]

I'm running a second 02 sensor spacer to avoid the CEL, but I wonder if standing the sensor off like it is could affect mixtures. On the run my car is doing low 12's (AFR that is!) which is ok, but at idle it smells rich since I got the dump/cat/spacer put on. Ever heard of a spacer causing that kind of thing?

How are you logging the AFR? The front probe is responsible for mixture regulation as far as I am aware. The rear probe has no influence on things.

Gavin

[sambb]

tailpipe. any idea what afr should be at idle?

[h100vw]

tailpipe. any idea what afr should be at idle?

14.7, you need to look at the measuring blocks.

[sambb]

cool thanks. VCDS cable coming soon.