Lambda Sensor (Oxygen Sensor)

[Mint]

Hi

I recently ran VAG-COM diagnostics on my car, and it found two faults:


00525- Oxygen Sensor (G39)
03-10 - No Signal - Intermittent

00522 - Engine Coolant Temperature Sensor (G62)
30-10 - Open or Short to B+ - Intermittent


Now we found that the faulty coolant temperature sensor was that cause of high idle speeds and so replaced it, but we turned a blind eye to the faulty O2 sensor as the car idled fine and seemed to run fine once the coolant sensor was replaced. However, i've been suffering from horrible fuel consumption lately and ive boiled it down to that O2 sensor. After looking it up in my haynes manual, i have found that this one sensor determines the fuel to air ratio and determines how lean your engine runs!! Therefore i have decided that i need to find out where it is located and how much it will cost to have it replaced. Would it be possible to take it out myself and see if cleaning it helps? Is the sensor expensive?

Thanks

[Ant_6n]

if you look under the front of the car to where the manifold pipe runs down to join the echaust and then the cat pipe there should be a gauzed of piece there is a plug going into this thats the lamda probe/sensor a new one from vag parts (bottom of the main page) will cost £68.74+vat (price from vag parts).

it is also possible to see the lambda probe from the top of the engine by either removing or looking to the side of the warm air collector plate (silver plate in front of the rocker cover with a hose coming out of it)

hope this helps

Ant

[Jay's MK4, Euro Stylee!]

Alrite mate,

Yeah changing the lambda probe can easily be done yourself, although the one thats in at the moment will probably be seized as fook, so you will av to be careful not to crossthread the the hole in the downpipe.

cleaning the original is not likely to help im afraid, when they are nackered they are nackered.

personally i would buy a universal lambda probe , presumably ures would be 4 wire the same as mine, they are the same thing as direct fit except rather than come with very long wires and a plug that plugs directly into the wiring harness on the engine, it comes with shorter wires which u connect using block conectors to the original wires. and the retail at around £40 - £43.

i have just bought one myself as i av been getting around 15 - 20 mpg from my 1.4 8 v for last 6 monthss!, thankfully i dont do many miles in it! i havent fitted mine yet tho as i have a 4-2-1 manifold waiting to go on.

Jay.

[vdubyabush]

same thing goes on my dads leon all the damn time

[Mint]

Hello

Thanks for the replies. I paid my local dealer a visit today to get a quote on the parts & labour; obviously, being VW, they quoted me £160 something. So i went to a small independant garage solely owned by one mechanic and he quoted me £71 parts & labour (the extra pound must be 50% towards his pint at the end of the shift ). It's going in tommorow at 11 so ill let ya know the outcome. The mechanic mentioned some of what you said Jay regarding wire lengths and the amount of pins. I think hes also ordered a universal lambda probe like you suggested.

Cheers

[Mint]

Sorted, although he charged me £15 to clear the ECU! (he said this was necessary) so that topped it off at £102. Shocking, i know, just to replace a sensor. Lets hope it doesnt go again anytime soon. There isnt really anyway of checking whether its working is there? It doesnt effect everyday driving, just the amount of fuel consumption should be noticed right? Anyway thanks for the advice, appreciated.

[Jay's MK4, Euro Stylee!]

yeah you shunt notice too much difference really apart from less frequent visits to the petrol station. which is always a good thing. In some cases it will drop the cars idle revs to normal levels, of course this will only be noticed if the idle speed was slighty high before changing the probe. not a massive difference tho, just that wen that sensors fooked your ecu dont know how much fuel its meant to dump in, so it just dumps s**t loads in and obviously affects the idle speed, as well as your wallet.

lol i go on way too much about stuff, shud be a car dude of sum sort, not a bloody Forensic Scientist in training!

jay.