Since getting the decat fitted I'm getting 16517 P0133 O2 Sensor Circ.,Bank1-Sensor1 Slow Response logged.

A search on here reveals that either the O2 sensor is busted (damage when fitting maybe?) or in one case they were re-fitted in the wrong place - front and rear swapped over.

This is possible! Is it obvious which sensor is which?

Also:

If you have access to Vagcom, look at block 031 under varying driving conditions - this will show the "target" and "actual" Lambda value from the front sensor, so you can see if the sensor is behaving (the two readings should match pretty closely)

Will check this tonight.

Hmm I'm no wiser really - the numbers looked similar.

VAG-COM Version: Release 311.2-N

Control Module Part Number: 06A 906 032 HN

Component and/or Version: 1.8L R4/5VT G 0002

Software Coding: 11500

Work Shop Code: WSC 00000

1 Fault Found:

16517 - Oxygen (Lambda) Sensor B1 S1: Response too Slow

P0133 - 35-00 - -

"in one case they were re-fitted in the wrong place - front and rear swapped over." This happened to a friend of mine. However, the car ran very badly for about a month until he figured it out. So I'm guessing if the car runs fine this is not it.

With a Decat you will always get an o2 sensor fault, since the o2 reading between both sensors in the exhaust is now zero, whereas before both sensors would have different readings. The CEL and o2 error are a side effect of running a decat on a vRS and little can be done to resolve the problem, if you clear the fault it will come back a few days later. This is why I fitted a sports cat to my old vRS, that way the sensors could still see a difference so I got no CEL or o2 errors.

I got that CEL and fault but my new Shark Performance remap removes it. This is a different one I think.

Are the pre- and post-cat sensors the same?

This is the DP - the pre-cat sensor is in the silencer part and might not be properly in the flow. I'm wondering if swapping the plugs over will help rather than having to remove the exhaust to swap the sensors?

The precat sensor on mk1 vrs is wide band 5 wire lambda sensor and post cat is narrow band 4 wire sensor.

Post cat sensor only is there to measure the efficiency of the cat, some people say it also make some minor adjustments but I don`t know that is true.

Best regards

Damn, I thought that might be the case.

Looking at the DP above, would swapping them help? Or would I be wasting my time?

I think it wouldn`t help because the second sensor is measuring the difference in oxygen level, now you don`t have cat to do this and the value is the same and ECU is throwing codes.

I was thinking to do the same thing but local tuning shop charges 150 euro just to remove the second sensor from the map.

I have read in FAQ 1.8T on vwvortex that OEM cat is not restrictive and can be used in aftermarket exhaust up 3" pipes, this was confirmed by several other tuning shops in my country.

I have read in FAQ 1.8T on vwvortex that OEM cat is not restrictive and can be used in aftermarket exhaust up 3" pipes, this was confirmed by several other tuning shops in my country.

Yeah I read that too. Interesting...

But Rob you don`t have a problem with second sensor, B1 S1 stands for Bank 1 sensor 1, that is the precat sensor.

Your sensor is probably faulty, if it has to slow response or value doesn`t change then I think the ECU is throwing this kind of codes.

Regards

Or try to make another hole before the silencer for precat sensor an plug this one. Maybe this is not the best place for wide band sensor.

Are the pre- and post-cat sensors the same?

This is the DP - the pre-cat sensor is in the silencer part and might not be properly in the flow. I'm wondering if swapping the plugs over will help rather than having to remove the exhaust to swap the sensors?

similar to my de cat only mine is un silenced and my 1st sensor hole is closer to the flexi pipe than on yours..how many miles or how long was it before your light came up?? ive done 200 miles and its been faultless with no lights and sounds amazing

Edited 1 February, 201016 yr by sivrs

Your fault is the first probe dude, swap it out for a new one, and i think you ll find problem solved, sometimes removing them causes the cel inside to crack or break which leads to failure, we ve put plenty of de cats on with no fault code issues

similar to my de cat only mine is un silenced and my 1st sensor hole is closer to the flexi pipe than on yours..how many miles or how long was it before your light came up?? ive done 200 miles and its been faultless with no lights and sounds amazing

The light came on after maybe 250km. If I clear the code it reappears after between 50-250km. It always comes on when I'm driving sensibly in a 50km/h limit

I wonder if the sensor was damaged when they fitted the decat.

Your fault is the first probe dude, swap it out for a new one, and i think you ll find problem solved, sometimes removing them causes the cel inside to crack or break which leads to failure, we ve put plenty of de cats on with no fault code issues

Sounds like it. Do you happen to know the part number?

You must sort it out soon because the precat sensor influence the fuel trims, running lean is a big NO NO for turbo engines!

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=180436835868&ssPageName=STRK:MEWAX:IT

Octavia vRS MK1 Lamda sensor B1S1 (The one before the cat) - AUQ, AUM engines

VW part # 021 906 262 B

Bosch part # 0258007057

Do you happen to know the part number?

Octavia vRS MK1 Lamda sensor B1S1 (The one before the cat) - AUQ, AUM engines

VW part # 021 906 262 B

Bosch part # 0258007057

Bosch is about half the price. Afther changing the sensor and driving the car about 20 miles the engine management light will turn itself off.

got this out the part number thread

got this out the part number thread

Doh! Good point.

Thanks all, will get one ordered.

Rob

Guys anyone passed a MOT with one of these Decats on???

This looks good at about 44 quid delivered - about $100 to ne

http://cgi.ebay.com/ebaymotors/Bosch-057-Wideband-Oxygen-Sensor-17014-Innovate-3737_W0QQcmdZViewItemQQhashZitem1c0f62d8d1QQitemZ120517220561QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories