Help, Please. 12 Volts At Pin 46
- Thread starter millertime187
- Start date
-
Sponsors (?)
@liljoe07 - This is going to be quite an education for all of us... Just when we thought that it worked one way, it seems to work differently. The previous owner may have done something weird that was needed to make things work at that time. The trouble is he didn't document it and now it has surfaced to haunt you...
At this point in time, the simplest route may be to cut and cap the wire going to pin 46. Leave a 6" stub on the computer end to splice a new wire onto. Then run the new wire to the places it needs to go. That would be the clutch switch and the NSS sensor on the transmission.
At this point in time, the simplest route may be to cut and cap the wire going to pin 46. Leave a 6" stub on the computer end to splice a new wire onto. Then run the new wire to the places it needs to go. That would be the clutch switch and the NSS sensor on the transmission.
Attachments
The problem with the diagram is that it doesn't show you all the wire and the loop that the O2 sensor harness makes to use the same body harness work fro auto trans and 5 Speed. The same thing can be said for the diagram I posted. There are some wiring and connections not shown for the auto trans for simplicity's sake..
Looking at this diagram, if you look at the pin 30, a/t side. The white/pink wire, it goes to starting/charging systems. But the m/t it doesn't. That would definitely feed 12 volts back. I wonder if that is my problem wire? If I was to find that wire and cut it, wonder if that would be it?
Yea I see that now, that white pink wire is the one that's jumped at the NSS, and with my tranny harness not hooked up, and it still having voltage don't make since it's that wire. So maybe if I disconnect every sensor one at a time that's on this circuit I may narrow down the problem. I shall try that and hopefully something shows up.
liljoe07
5 Year Member
This is typically how 12v gets sent to pin 46 to begin with. In an Auto setup, the ground to pin 30 is sourced from the starter solenoid control wire. The red/blue one. I know it sounds confusing, and it is. But that is how Ford did it. They use the relay coil to get the ground when there is no 12v flowing through it, as that will read as a ground when not starting the engine. So if you ground pin 30, you will have a short when starting. Im starting to agree with JR, and I am thinking the previous owner did something fishy.
I didnt see it mentioned, but is the 12v only showing while you are cranking the engine, or is it still showing even when you are not cranking the engine?
Ok, I have a weird development, I was just out there until hooking every plug I could see. Nothing was making voltage go away. Then I noticed I had the code reader I just bought still hooked up, so I unhooked it. Now I only have .3 DC volts at pin 46. Lol. I hook it up and get 12 volts. So this nice code reader may have been my thorn the whole time? Does this make sense?
So my question is .3 volts ok? And do I have a default reader that has been my prob this whole time? :/
So my question is .3 volts ok? And do I have a default reader that has been my prob this whole time? :/
liljoe07
5 Year Member
No I can leave that unhooked and still have 12 volts with that scanner hooked up. But when I unhook that scanner with the bigger plug it goes away. I just started it, no more check engine light. Not sure what's going in but it's either that scanner or the main plug for scanner.
liljoe07
5 Year Member
Not sure the scanner is the issue. Some people have used the hood light connector by accident. That's why I asked if that plug had 12v on it. Scanner is battery powered correct? Nothing in the code test port should have 12v technically. The fuel pump ground may show it, when no ground is applied to the relay. The STO is a pulsed ground from the ECM, its tied into the check engine light. Which has 12v on the opposite side of it. STI is a 5v circuit, and SIGRTN(pin 46) is a ground. What are the voltages to the wires in the code test port?
liljoe07
5 Year Member
liljoe07
5 Year Member
That is the fuel pump trigger wire, which I mentioned would have 12v when no ground is applied to it. So it looks like your scanner is the issue. Has it ever worked correctly before?
No I just bought it. This was the first time using it. So that wire should have 12v?
Both you guys have been way more than helpful, if either of you want some real kentucky moonshine or something let me know. I owe both of you for responding and keeping me on this problem!!! Just pm your address and I'll send you some real 
I'll edit this post tomorrow so everyone in the world doesn't see this post
I'll edit this post tomorrow so everyone in the world doesn't see this post
liljoe07
5 Year Member
Correct, 12v will flow through the relay coil winding when there is no ground applied. perfectly normal. And I appreciate the offer, but that stuff will get me into trouble! LoL! Enjoy your ride man!
Similar threads
Digital Tuning
I'm Back! Do I want a Megasquirt?
