Any idea what this is... (996 O2 sensor cable related)

[Lamplighterson]

So, hooked up the 996 to the durametric software. I'm getting the error codes shown below:



So I went in search of the O2 sensor plugs. Due to my model year of car I only have 2 sensor plugs rather than the 4 on later cars. Found the following...





This small "Bosch" box has been fitted (crudely) inline between the actual sensor and the regular plug. It's certainly poorly wired and when I move the wires around and then retest the engine the codes are gone. Move the wires again and it returns.

So there is the fault. I will be soldering the wires if it transpires I need to keep this small box.

However - what on earth is this small box? My exhaust was changed by a previous owner to a Cargraphic sport exhaust. Is this box to fool the ECU perhaps?

Inside the box behind the cables are small yellow plastic screws and what looks like plastic gears?

A patent search brings up the following:

http://www.google.com/patents/US6672900

But strange that only one O2 sensor has this? Do I even need this? It's been spliced in.... Without it the reuglar plug would have fit into the connector as shown - this is purely spliced into the wires...

Edited by Lamplighterson on Wednesday 10th April 15:46

[Lamplighterson]

So it seems to be a splice box. I'm not sure if under the electrical tape are joins - would be idiotic if they were as the box is supposed to do that job! Will check.

[Lamplighterson]

And the answer for reference:

http://www.e90post.com/forums/showthread.php?t=748...

[ricola]

Well you found the answer, as to why, I've tried soldering the wires before and they don't so can only assume they are coated in something that isn't solder/flux friendly..

[Rockster]

ricola said:

Well you found the answer, as to why, I've tried soldering the wires before and they don't so can only assume they are coated in something that isn't solder/flux friendly..

The O2 wires are not coated with anything unfriendly to soldering.

But you should not solder to join O2 sensor wires. The solder can affect the voltage signal sent from the sensor (it can bias it) and this can cause all sorts of hard to diagnose issues.

There are crimp type connectors with a capsule of sealant as part of the crimp so that when it is crimped the sealant is expelled around the wires to make a moisture proof connection.

[Lamplighterson]

Thanks folks. Will take a closer look at the box tomorrow and check the connections.

I think I'll replace it for an original part on the next service though.

[Richard Hamilton]

Probably incompatible sensors, don't you think?

[Lamplighterson]

Quite possibly. One is oem, one is aftermarket. The aftermarket one will be changed for oem on the next (due) service.