# OBD1 Motronic -> Vanagon O2 Sensor Plug. 5th Black Wire: Shield? PIC



## Vanagon Nut (Oct 19, 2007)

Hi all.

Swap runs "ok" but b/c I moved the O2 sensor to manifold, noticed the wires were taped too "tight" to the plug. Unwrapped tape, saw the mystery wire.

Does the black wire shown connect to the O2 shield? If so, diagram 97-17 in A3 Bentley shows it as grounded but does this end connect to ground or is other end supposed to be? (ran out of day light so didn't test)

If it's not the shield, what is it for?

Thanks

Neil.


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## Vanagon Nut (Oct 19, 2007)

Ok. Found an online diagram showing the solid wire in Bentley as a black wire. That wire shows continuity to ground so it grounds via some other point in harness. Not sure why VW has that lead there. Maybe an option for grounding elsewhere during assembly? Anyhow..... 

It "smoked" through emissions! 

Neil.


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## ps2375 (Aug 13, 2003)

Wow, was it running during the test?


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## Vanagon Nut (Oct 19, 2007)

ha ha. Ya I know. 

Emissions goes by the VIN, so would test for an '81 air cooled Vanagon. 

Not sure if the '81 base line figures affects the actual outcome. 

AFAIK, up here, the '81 didn't require a cat. Though the cat I installed was noted in their report. 

Neil.


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