Oxygen Sensor

on the 3B motor 1991 200 20V Turbo

Click here for a Vag-Com diagnosis to check if yours is good

Here we change out the O2 sensor.

READ about the two types below:

Brand New Bosch super Mac Daddy with "OEM" brand O2 socket.

Here the replacement part comes with the tip covered by plastic

with high temp grease on the threads underneath.

Here is the auto part store ~$13 socket.

Apply a penetrating oil liberally, a few times before removal.

The threaded "bung" is on the downpipe in plain sight.

Whata breeze!  Old sensor looks plugged with ash.

Here's a close up.  Notice the compression crush washer used.

New O2 sensor close up of tip and lens cap.

Plastic cover protected the high temp grease for the threads.

Now here are two options:

There is a "generic" o2 sensor that some listers from Audifans.com

use from a Ford.  The average price is ~ $40.00  Part # xxxxxxxxx.

That route needs to have the three wires cut and

spliced into the old harness from the firewall.

Photos to come.

Buy the "plug and play" ~ $130 version:

Part number: xxxxxxxxx

Audi 3B & MC after Vin F44K038.262:  034 906 265F

I figured this would be a simple swap.  NOT SO.

Here the sensor has TWO long wires to run all the way to the firewall.

Here are the connectors on the firewall behind the motor.

The lowest TWO are the oxygen sensor leads.

Above is a closer photo.

The lowest connector appear(s) to be the ground.

Here is the ground rubber boot to cover the spade connector.

Notice my hand around the connector.  Notice the metal "clip"

Below the thumb presses the "clip" in to release.


Click on photo to enlarge.

Here is the damn thing released.  Above:

Notice the detent to "click" together the connector(s).

The red connector above is also used as an example.

The photo also shows the bracket to hold the connectors.


Here is how it slides on to click together:

To remove:

The metal "clip" is then pressed up to slide connector apart to the left.

Remember to zip tie the long lead folded over on its self to the other

wires along the fender to keep from the HOT exhaust.

Now your DONE !


Aug 25, 2004 its acting up! CEL

Hmmmmm. Power just not there. 

I have to press deeper into the peddle to make it go.

Here's the DTC (problem) from Vag - Com above.

Here's what the Bentley manual says about it.

So I log into Block 000 for the ten data fields (sensors) and

calculated values to get this confirmation about the O2 sensor ( field # 8 )

160:  Should be "MUST fluctuate around an avg., of 120"

Table above shows range of 123-133


Table reference from the Bentley

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Updated Aug 24, 2004