Why would someone remove a Fuel Temperature Sensor?

[Tyroaudi]

I have had an intermittent (sometimes faintly glowing) Emissions light on the dash for a while. Never on at startup but comes on after 30 minutes to an hour or so.
I had a VCDS diagnostic run (thanks very much MattD) and the only fault was 17571 - Fuel Temp Sensor (G81) P1163 - 35 -Open or Short to Plus.

Could this be my Emissions problem?

Recently, when servicing the car I found a black block with 2 tubes exiting from it and connected to a green and white wire hanging, not connected to anything, next to the fuel filter. Car seemed to run OK so I ignored it for a later time. When MattD looked under the bonnet he identified it as the FTS!

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Question 1: Is this the FTS?
Question 2: Why would anyone disconnect the FTS from the fuel system?
Question 3: How can I identify the fuel line I need to separate to re-fit the FTS?
Question 4: Would a faulty FTS cause the Emissions light to come on, given that there are no other faults?

The car is a 2004 A6 C5 1.9tdi AWX 130bhp.

[Peter D]

PM me your email address and I'll send you a diagram. Yes it is the FTS. Regards Peter

[rowdy-999]

I imagine it must have been faulty, so rather than replace, they bypassed it.

[Tyroaudi]

The plot thickens!!

I've now had a chance to get under the bonnet properly and found, with the help of diagrams from Peter D, that the FTS is still in situ. However, for some reason a totally separate FTS had been botched/wired into the loom in place of the original one and left free and dangling in mid air.

One of the wires on the extra FTS has come adrift so I have removed the whole shebang and temporarily isolated the connections. Since there is no plug/connector on the end of the wires, they were just crimped spade connectors pushed into the FTS, I guess I'll have to contact Audi for a new one (if they supply such a thing) or maybe visit the local scrappy's to see what I can find. Certainly the job of getting hands into such a cramped space to do some soldering will be a trial so I guess I'll have to remove some of the pipework around it.

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