Q45: Sensor on Y Tube Under Plenum?

[sdkhalsa]

What is the sensor on the Y coolant tube under plenum between and forward of knock sensors? I thought it was a second engine coolant temperature sensor, but that doesn't sound right.

[maxnix]

Do you mean the engine coolant temperature snesor as displayed on EC-10?

[sdkhalsa]

I believe that the sensor indicated on EC-10 is the one located on top of the thermostat housing and next to the gauge temperature sensor in the front of the engine. If you go to q45.org(http://www.q45.org/plenum.html) under the removing plenum instructions, go down to the last picture before the shop photos and above the paragraph "Supplemental Information", you will see a perfect overhead view on top of the Y channel.

[maxnix]

And where is the sensor to which you are referring?

[sdkhalsa]

I think that I figured it out. On diagram EL-254, it appears to be connector S22, TCS temperature sensor.

[sdkhalsa]

It is the rust red connector just to the left of center, middle of "y" coolant channel between the two head banks. If you look on LC-10, there are two engine temperature sensors. This is the one on top.

[Raxephon]

It is the rust red connector just to the left of center, middle of "y" coolant channel between the two head banks. If you look on LC-10, there are two engine temperature sensors. This is the one on top.

Actually there are 3 for the '94 Q45t, the normal 2, of which one has a blade connector,(that one is for the instrument cluster), and one that has 2 pins in a red plastic recepticle,(that goes directly to the ECU).

The third is located in the middle of the coolant crossover pipe that sits between the cylinder heads and just above the "X" crossbracing cast into the top of the block.(I do not know the exact reason for this third sensor since this is my first Traction model Q45, but it seems like a great place for an aftermarket coolant temperature sensor)