V6 Replace Pre Cat Oxygen Sensor Bank 2 Drivers Side

by: FrankGant


NOTE: Please keep in mind that PassatWord input from posters indicates this cat fault may be due to overly sensitive ECM which can be fixed by
a dealer reflash/update.

Error Codes Associated With This o2 Sensor (these are the codes I got):

P1131 Bank 2 - Sensor 1 Internal Resistance too High - Drivers Side
P0431 - Warm Up Catalyst: Bank 2: Efficiency Below Threshold - Drivers Side


  • Phillips Head Screw Driver
  • 11" extension for 3/8" drive wratchet
  • 3/8" drive wratchet
  • Wire strippers
  • Wire cutters
  • Oxygen Sensor Socket Kit (can be barrowed from AutoZone with Deposit)
  • WD-40
  • Anti-Seize for new o2 sensor threads (new sensors come with some on them, but it's not nearly enough)


  • Bosch 15733 Universal Oxygen Sensor purchased at AutoZone for $69.00 + tax.

  • To get started, remove the 3 phillips head screws holding on the coolant reservoir and then move it to the side.
  • With the reservoir to the side you how have access to the area you will be working in.
  • The oxygen sensor is located behind the motor and below the connectors you see circled on the firewall in the above picture. You'll have to move around a bit to find the best place to stand to work. I leaned over the fender to see the sensor with a clear view.

Now is a good time to spray on a liberal amount of WD-40 on the o2 sensor where it meets the exhaust. We'll let this soak in to help loosen it up.

  • Before we start to remove the oxygen sensor, lets go ahead and disconnect it from the car. The connector is the large black one and the farthest left in the cluster of connectors circled in picture 2. Below is a close-up of that connector.
  • Once disconnected you want to work with the male end pictured below. This is the end of the connector that belongs to the oxygen sensor. Slide the heat shielding on the wires down so you expose 4" to 5" of the sensors wires. Cut all 4 wires evenly just above the heat shielding making sure you have 4" to 5" to work with. DO NOT CUT ON THE FEMALE CONNECTOR!
  • Once you have the male connector cut loose you can remove the oxygen sensor. You will want to use the 7/8" (22mm) black socket supplied in the kit you can borrow from AutoZone. I tried the silver socket but could never get it seated properly over the sensor. Using a wratchet and the 11" extension along with the 7/8" o2 sensor socket you should easily be able to remove the o2 sensor.
  • After you have removed the old oxygen sensor you will want to follow the directions in the Bosch 15733 Universal Oxygen Sensor Kit. The directions clearly tell you how to connect the old oxygen sensors male connector that we cut loose, to the new sensor. Once you have done this if you ever need to replace the oxygen sensor again you won't have to cut on any of the wires in the car. You'll have a new (second) connector between the male we've cut loose and the oxygen sensor.

Link to BOSCH 15733 Universal Oxygen Sensor Kit Instructions (.pdf format): http://orbitpinball.com/personal/passat/univ_oxygen_sensor_bosch_15733.pdf

  • After you've finished with the BOSCH kit instructions you should apply more anti-seize to the threads of the new o2 sensor. Now just simply install everything in reverse order.

*Clear Fault Code if necessary if it return see if the dealer will flash/update your ECM.

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