Wiring AEM oil pressure sensor

I bought an AEM oil pressure sensor after reading it would fit under the alternator. It does fit, but the sensor is a three wire connection, not a single wire. The signal wire will be wired to my TGV harness. The yellow wire feeds into the ECM, and my tuner will display the oil pressure on my Cobb Accessport. There are two other wires on the AEM sensor: Signal ground (easy enough to ground it), and a 5V power wire. This is the first time I've seen a sensor that needed a power input. I looked through my LGT repair manual, and saw several 5V outputs from the ECM. One is marked sensor power supply #1...there's also a sensor power supply #2. That sounds perfect...I couldn't cross reference to the wiring harness to identify where they are, and what color wire goes into the B126 connector at terminal 17.

 

Has anyone wired up this pressure sensor, and where did you get your 5V power supply? I was hoping one of the TGV wires was a 5V, but I don't want to fry my ECM poking and prodding the harness. Thanks!

Sorry...fat fingered and scrambled the numbers. The connector is B136, not B126. I plan to pull the carpet and look at the ECM to see if the plugs are numbered, but would prefer to get the 5V off the TGV harness, if that's an option. Thanks!

OK...new details. AEM got back with me, and said to use the sensor 5V and sensor ground circuits for the fluid pressure sensor. I shoved in the Subaru repair disc, only to find out I was sold the wrong disc back in 2005! This shows just how reliable a Subaru is, if it took a dozen years to figure out I had the wrong manual. Plus, there's so much interchangeability between models that the "wrong" manual worked fine for my engine rebuild. But wiring harnesses are another story.

I found a copy of the Engine Electrical System wiring diagram on LGT.com, and wanted to confirm the BL (black/blue) wires from the TGV angle sensor was the ground circuit, and the BY (black/yellow) was the 5V power supply. I am super paranoid about frying my ECM. Thanks to the community for your help!

subbed...interesting

I got out the Fluke multimeter today. I cut the right TGV sensor wires and soldered in 2 foot extensions: red for the White/Red sensor feed, blue for the black/blue 5V, and black for the black/yellow 5V. I learned the black/yellow is the 5V ground, and the black/Blue is the 5V power. I wrapped the three wires with electrical tape after heat shrinking the soldered connections, and ran the wire bundle along the harness towards the front injector plug. I then shoved the wire under the turbo intake hose and wired the AEM plug per their directions. I still have to do my AEM wideband o2 gauge and sensor before I get my tune done, but I am confident my oil pressure will now be displayed on my Cobb Accessport.

Is the tgv ground variable?

That's ecu frying territory maybe...

The body ground/ecu ground scenario discussed in the btssm thread here

http://legacygt.com/forums/showpost.php?p=5539518&postcount=1980

Starting from around page 131 logging via rear o2 is discussed

Is the tgv ground variable?

That's ecu frying territory maybe...

The body ground/ecu ground scenario discussed in the btssm thread here

http://legacygt.com/forums/showpost.php?p=5539518&postcount=1980

Starting from around page 131 logging via rear o2 is discussed

 

I read your linked post, and since I want to feed the sensor signal to the ECM, I use the sensor ground circuit. I am still waiting for delivery of my AEM wideband kit, so the car is just sitting in the garage. Once the wideband O2 is in place, I will get an e-tune from Mike McGinnis as the first step in a dyno tune process. The Accessport display will then let me know if I wired the oil pressure sensor correctly. Thanks for the link...I would not have read the BTSSM thread and found that.