Fuel temperature sensor?

[Mozambiquer]

I have a code on my passat for the fuel temp sensor, just wondering what function it has on this car? Will it make any difference if it's not working? I'm just wondering if I should go through and diagnose what's wrong that's setting that code? I guess I can hook up and get the code here soon...

 

[oilhammer]

Diesel fuel's viscosity changes as it warms up, so the ECU's injection timing etc. is modified to take this into account. All TDIs (and all modern diesels) use one.

It is in the hose back kind of behind the fuel filter on the BHW, but there is a chance that it is the wiring or connector, too.

 

[Mozambiquer]

Diesel fuel's viscosity changes as it warms up, so the ECU's injection timing etc. is modified to take this into account. All TDIs (and all modern diesels) use one.

It is in the hose back kind of behind the fuel filter on the BHW, but there is a chance that it is the wiring or connector, too.

Ok, so it probably would mess with start of injection and timing, which could affect efficiency/power?

 

[oilhammer]

I think the ECU likely just goes by some other default value (like coolant temp) to "guess" the fuel temp in the event this signal is lost. So chances are, you may not notice a huge difference in the way the engine runs from the driver's seat. Not really sure, I've never not fixed something like that because it is simple and cheap and easy.