Volkswagen Passat Forum banner
1 - 9 of 9 Posts

·
Registered
Joined
·
11 Posts
Discussion Starter · #1 ·
I"m changing both of the post cat O2 sensors on my 2005 B5.5 ATQ V6.

1: there are four O2 sensors but I only see 3 plugs on the passenger side when I open the hood. Shouldn't I see 4 plugs along the cowl?

2: The bank one sensor plug in the engine compartment is a different shape than the bank 2 plug. The dealership says that there is only one part number though. Anyone run into that before?

The O2 sensor change post in the information base has no pictures any longer. Is there one with pictures that I haven't found yet?

Thanks!
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #3 ·
Been getting a code from one or both intermittently for a while. One gives no signal at all most of the time I have a scanner plugged in. The other is also ten years old and throws a code occasionally. I had a consistent misfire that I fixed. I"m hoping that the cat is alright on that side but if it isn't I'd be replacing the bad sensor along with the cat anyway.
 

·
Registered
Joined
·
29,164 Posts
The 4th plug is behind the coolant tank, driver's side front sensor. The plugs were different color, but I don't recall them having a different connector. Make sure you have the correct plug. The fronts were both black, the rear were a green and a brown (if memory serves).
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #5 ·
That makes sense. I bought on from the dealer and it was a black connector instead of green or brown. It fit the green connector but the brown one had a lip on it that prevented it fitting. It felt like they make it fit slightly differently so that you don't accidentally use the wrong one.

Any guesses? On third party sites some identify a specific side for each sensor and some don't.
 

·
Registered
Joined
·
11 Posts
Discussion Starter · #7 ·
Here's the difference in the connectors:




As you can see, the brown current connector has two flanges on it that prevent plugging the dealership connector in.

They included in the kit both the male and female sides of the connector so that I could replace the brown plastic entirely but it seems strange that the factory would go to the trouble of installing two separate parts for no reason.
 

·
Registered
Joined
·
29,164 Posts
The 2 fronts should be identical, the 2 rears should only be different colors. If you plug the rears into the fronts, it would create problems as the readings would be thrown off, but the sensors themselves are the same.
 
1 - 9 of 9 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top