davecheng

My B2S2 O2 sensor went dead (open circuit) so I set out to replace it. I had a brand new four-wire Bosch O2 sensor (for a VW Passat/Audi A4 1.8T ABA) sitting around and I decided to splice it in to the existing wiring.

Polarity of the two heating element wires was verified with a wiring diagram from Elsa. I used top-quality Wurth heat-shrink butt connectors to do the job.

The car is now throwing a different O2 sensor code:

<pre>17518 - Oxygen (Lambda) Sensor Heating: B2 S2: Heating Circuit Short to Plus</pre>

I measure the resistance across the heating element circuit in my replacement sensor at 5 ohms. The existing, good O2 sensors are all at 10 ohms.

Before I go out an buy another cheap four-wire VW Bosch sensor, is there anything else I should try?

What is the most commonly used VW (or less-expensive, but identical) O2 used for secondaries on these cars? Part no.?

p.s. Pic for views.

<img src="http://pictureposter.audiworld.com/114290/s4_i3z9901-1.jpg">

2000SForce

Log your o2's and see what they are doing there is a slim chance they will be doing their job.