I had my 2001 1.4 mpi Comfort scanned by VAG Com and under the engine it produced these fault codes:

16555 - Fuel Trim; Bank 1

P0171 - 35-10 - System Too Lean - Intermittent

17549 - Load Calculation Cross Check

P1141 - 35-10 - Implausible Value - Intermittent

16514 - Oxygen (Lambda) Sensor B1 S1

P0130 - 35-10 - Malfunction in Circuit - Intermittent

17524 - Oxygen (Lambda) Sensor Heating; B1 S1

P1116 - 35-10 - Open Circuit - Intermittent

16500 - Engine Coolant Temp. Sensor (G62)

P0116 - 35-10 - Implausible Signal - Intermittent

17978 - Engine Start Blocked by Immobilizer

P1570 - 35-10 - - Intermittent

18058 - Powertrain Data Bus

P1650 - 35-10 - Missing Message from Instrument Cluster - Intermittent

17911 - Load Signal from Alternator Term. DF

P1503 - 35-10 - Implausible Signal - Intermittent

I believe that i have caused some of these ( i.e 16500, i had an air lock in the coolant system, 18058, i had the dash board out & didnt plug in the instruments correctly, 17911, ive recently replaced the alternator due to a bearing fault with one from a breakers.) but a majority seem to be pointing towards the lambda sensor being faulty.

I live in Medway and i drove to broadstairs with the sensor unplugged and it did not appear to affect performance in any way and it wasnt until i arrived there the EML came on.

Im unsure about it tho because some fault codes point towards a vacuum leak as 16514 says its intermittent therefore the sensor is working some of the time?

does anyone have any ideas?

load signal from alternator fault code is that normal blue or brown wire issue in front of gear box, or you have not plugged the little thin wire back onto alternator

ok, but do you think i have a vacuum leak or just a faulty lambda sensor?

I would check the connections to the dash, altenator and anything else you have disturbed. Then clear the fault codes and go for a short drive and then see if any codes reappear.

Steve

16514 - Oxygen (Lambda) Sensor B1 S1

P0130 - 35-10 - Malfunction in Circuit - Intermittent

17524 - Oxygen (Lambda) Sensor Heating; B1 S1

P1116 - 35-10 - Open Circuit - Intermittent

16500 - Engine Coolant Temp. Sensor (G62)

P0116 - 35-10 - Implausible Signal - Intermittent

17978 - Engine Start Blocked by Immobilizer

P1570 - 35-10 - - Intermittent

Sorry to revive this after nearly a year, but did you eventually get this sorted?

I've had the above codes myself on the wifes' Fabia over the last three years, its a 1.4 16v, AUA engine code.

The immobiliser one has only happened once, the coolant temp one happened repeatedly for about 6 months then suddenly disappeared, but the lambda codes are doing my head in! I've replaced the back one as at first thats what the codes were for, then it threw up a MAP sensor fault code, which I (stupidly) tried to replace with a pattern part, that sent the auto gearbox/torque converter up the wall! I put a genuine one in and that cleared, and now it comes up with all sorts or codes seemingly at random, all pointing at the front lambda sensor!

All this is accompanied by high emissions that means its struggled to pass its last two MOTs...

I've been into my local dealer and they said that they 'rarely if ever' have to replace front lambda sensors on Fabias (I'm on quite friendly terms with them!), saying instead that they cut the plug off and wire it with bullet connectors or similar.

Now, I've got a full wiring diagram for the Lambda circuit etc and it shows a resistor between wires 2 and 4 in the plug itself, so how can they do this without there being either a resistor missing or a mess of connectors and a resistor stuck behind the radiator?!

Beginning to think its not worth the penny pinching of altering the connections and bite the £160 bullet for a new sensor and hope for the best!

Cut the red wire....no hold on, the blue wire.....no, the red wire.....

16514 - Oxygen (Lambda) Sensor B1 S1

P0130 - 35-10 - Malfunction in Circuit - Intermittent

17524 - Oxygen (Lambda) Sensor Heating; B1 S1

P1116 - 35-10 - Open Circuit - Intermittent

As you know practically all petrol Mk1 fabias have two sensors.

Exhaust Manifold -> Lambda Sensor Bank 1 Sensor 1 -> Small Cat -> Lambda Sensor Bank 1 Sensor 2 -> Back Box n Silencer.

On the AUA/AUB engine at the front of the engine bay there will be a piece of metal covering the exhuast manifold under there will be the O2 sensor. As its saying both Open Circuit and Intermittent fault I would suggest tracing the connector and cleaning the contacts then ensure its reconnected correctly. If that doesnt work i would suggest changing the sensor.

If you cut the cables and solderd them it should not need any other mods as i doubt the resistor would be fitted in the connector and could be a circuit symbol for the heater element for the sensor itself.

Is it a wideband/broadband sensor?

If so there may be a calibration resistor in the connector housing, to 'tune' each sensor after test. Remaking connections without the plug would seem inadvisable.

From http://www.bosch.com...s/Section_a.pdf

"Broadband oxygen sensors can only be used in conjunction with a

control unit that is specially designed to support the operational

function and precise heater element management required by an LSU

broadband sensor. It is important to note that a specifically designed

wiring harness connector containing 6 pins is used for LSU type sensors.

Whilst the physical appearance of the oxygen sensor connector will

vary according to customer and vehicle design requirements, all LSU

sensors have a calibration resistor built into the connector housing.

Each individual LSU sensor is calibrated at the conclusion of the

manufacturing process by laser altering this resistor value. Therefore

removal or exchange of the oxygen sensor connector will render the

sensor inoperable."

Is it a wideband/broadband sensor?

If so there may be a calibration resistor in the connector housing, to 'tune' each sensor after test. Remaking connections without the plug would seem inadvisable.

From http://www.bosch.com...s/Section_a.pdf

"Broadband oxygen sensors can only be used in conjunction with a

control unit that is specially designed to support the operational

function and precise heater element management required by an LSU

broadband sensor. It is important to note that a specifically designed

wiring harness connector containing 6 pins is used for LSU type sensors.

Whilst the physical appearance of the oxygen sensor connector will

vary according to customer and vehicle design requirements, all LSU

sensors have a calibration resistor built into the connector housing.

Each individual LSU sensor is calibrated at the conclusion of the

manufacturing process by laser altering this resistor value. Therefore

removal or exchange of the oxygen sensor connector will render the

sensor inoperable."

Thats exactly the info I was after, thanks alot! Looks like I'm buying a new sensor then....

I'd go further and make sure you save money by buying either a VAG marketed one or one from an NGK vendor as VAG tend to use them under the NTK brand name, though in my experience, the local VAG dealer charges about the same as you can buy online if buying P&P. The front sensors do seem to go on the later "B" series of petrol engines.

BTW, both sources I suggested will sell you the correct sensor already fitted with its cable and connector.

Edited 29 April, 201313 yr by rum4mo

Okay,

So, bought a replacement genuine NTK sensor from Gendan, fitted it, cleared the codes, started up, no light. For the first 5 seconds anyway, then back it came, the code is still 16522.

I'm getting really pi55ed off with this car now....

Are you serious, that Lambda sensor gets ignored for longer than that - so should not throw out a fault code. BTW, that code seems to be for the second, ie measuring sensor.

The high emissions caused by the failure of your front O2 sensor have fouled your cat and the post-cat probe, take the car for a good long fast run on the motorway to burn it all off and it should clean up.