Oxygen sensor malfunction in circuit fault?

[sponger]

Done lots of searching and not come up with any conclusive causes or things to check.

Had a recurring fault code of: 16514 or P0130 - Oxygen (Lambda) Sensor B1 S1: Malfunction in Circuit.

I replaced the pre-cat lambda with a brand new Bosch sensor today but sadly the fault appeared again.

Car runs smoothly, no hesitation or lumpy running, idles fine. Not sure on MPG but it's returning about 30mpg at the moment, although I haven't been booting it everywhere.

Checked the wiring around the connectors but all seems fine, however a lack of a decent manual and wiring diagrams leaves me stuck on where to go from here. I bought a CD from eBay with a workshop repair manual on it but it's far from ideal unless you have full access to the VAG diagnostic kit!

I have a cable and vcds lite, however it's not a lot of use other than reading and clearing faults unless it's the full version.

Any pointers and info of what/where to check would be greatly appreciated as I am totally stuck at the moment!

Many thanks in advance....


Oh, it's a 2002 Seat Leon 1.8T 20V Cupra.

 

[sponger]

This is the fault code that came up:

VCDS-Lite Version: Release 1.2
Tuesday, 26 November 2013, 13:27:33.


Chassis Type: 1M - Seat Leon/Toledo
Scan: 01,02,03,08,15,17,19,22,35,36,37,46,56

-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AJQ.LBL
Controller: 06A 906 032 HN
Component: 1.8L R4/5VT 0001
Coding: 11510
Shop #: WSC 06441
VCID: 719556C728B1
VSSZZZ1MZ#***~~**** SEZ7Z0A~**~*~*
1 Fault Found:
16514 - Oxygen (Lambda) Sensor B1 S1: Malfunction in Circuit
P0130 - 35-00 - -
Readiness: 0000 1101

 

[MJ]

Internal sensor fault or wiring.

 

[sponger]

As I said above, aware of the fault, sensor has been replaced.

Have no wiring diagrams so was after info of how/where to check to rule out wiring.

Even Ross-tech wiki is of little use.

 

[MJ]

When wires break they tend to do so with a foot of the component, does the loom trace back towards the bulkhead? If so it might be chaffed.

Can you read live data from the sensor? If it reads 0.0 then there is a definite break in the circuit.

Might be worth checking the pins in the connector have no corrosion and haven't been opened up to wise as well.

 

[sponger]

Checked the connector pins, all good with no signs of moisture or corrosion.

Not sure if I can check live data on the unregistered vcds-lite? To be honest it doesn't seem to do a lot. Wish I had paid out to register it rather than buy a new lambda sensor!

Will try and trace the wires up, from what I gather there is a test connection under the wiper cowling, just not sure on correct pin numbers?

 

[MJ]

Does the fault return immediately after it's erased?

 

[sponger]

Yes and no, first time I reset it, did a couple of hour journeys and nothing then it popped up on the next trip (engine still warm).

Next time it was similar, this morning it appeared during a short journey, then the last time after changing the sensor it came up again quite soon, another short journey, reset and again a couple of short journeys and it's on again.

It doesn't come straight on after resetting, but getting no other faults.

 

[sponger]

Right, did some wiring checks today up to the ECU from the sensor plug.

Had to dismantle the ECU plug to find out the pin numbers! However it was fine, continuity and low resistance so nothing to suggest a wiring fault?

So where now? Any ideas?

 

[sponger]

And so it continues.....

Did an ECU reset late yesterday, thought it had cracked it!

Then lo and behold on came the light this evening

I am really at a loss now.