Re-using a Sensor Ground wire

[Ricco]

I have a Link G4x plugin for Impreza STI (WRXLink V10).  I am no longer using the MAF and have already rewired the IAT from the stock MAF location to an aftermarket IAT sensor. This leaves 3 wires from the MAF connector, +12v, MAF signal (Shielded) and MAF ground. 

I'm trying to wire in a Link Combined Pressure and Temp Sensor using the leftover MAF wires.  The new sensor needs 5v vs the 12 volt that was being supplied to the MAF, so I was planning on grabbing Sensor power and ground from the MAP sensor wiring, and using the 2 remaining MAF wires for the 2 required signal wires on the CPTS.  

The question is, will the MAF signal wire work for Oil pressure if I'm no longer using the dedicated MAF ground wire for that sensors ground? I want to repurpose the MAF ground wire and connect it to an expansion loom for the Oil Temp side of the sensor. 

In summary I want to wire the CTPS as follows 

https://linkecu.com/documentation/WRX10X.pdf?_gl=1*10ymesd*_ga*MjAxMDY2MTEyNS4xNjk4ODA0NDUz*_ga_YGEEXMZ8NR*MTcwMDE2OTg1MC43LjEuMTcwMDE2OTk0Ny4zMi4wLjA.

5v - pin C16

Sensor ground - pin C35

Pressure Signal - pin C23

Temp Signal - pin C31 - Depinned from the ECU and redirected to an expansion loom

Hopefully that makes sense.

 

[Adamw]

I only have a very low res pic of the wiring diagram for the 04 pinout, but I think you will find the maf ground wire doesnt actually go direct to the ecu on its own, it will go to a slice somewhere, im not sure if this is near the ecu or somewhere else in the loom.

[Ricco]

Thanks for the reply, Adam.

What you're referring to is pin 5 on the maf connector which is the common ground that’s already been re-used for the IAT sensor.

The ones that are left are pins 1,2 & 3 on the maf connector.  

1 is 12v (orange I think)

2 is maf sensor ground (black and green wire) - Goes to pin c31 at the ECU

3 is the shielded maf signal wire (pink and blue) - Goes to pin c23 at the ECU

I want to use 2 and 3 for the ctps signals and generic 5v/sensor ground, to power the sensor. I just need to confirm that will work if I use a generic sensor ground, and repurpose the dedicated maf sensor ground.

 

Thanks,

Richard.

[Adamw]

It looks like it should work in that case provided that wire is not spliced to anything else.  You also have AN temp 3 on C12 so you may just be able to move the pin from C31 to C12 to make temp 3 available at the maf plug.

[Ricco]

Awesome! Thanks again.  I'll need to check if I have a Fuel temp sensor, but using AN Temp 3 might be a good idea. Thanks for the tip.

 

Thanks,
Richard.