Needing help with PCM connectivity 01 ST

[410Fortune]

I’m Not interested in voltages on those wires as much as resistance (ohm) and continuity (connected at both ends)

The ground and power wires should show dang close to battery voltages

 

[SKW1020]

I would start with a simple continuity test if the scp bus wires + and - from obd2 port to the pcm connector
(Pins 15 and 16)


Verify ground at pins 24 and 25 and 51 and 103
Then you can verify you have power at the pcm connector with the key off
Pin 55 keep alive power

and then with the key on
Pin 71 and 97

Simple Multi Meter tests will tell you a lot!!
Let us know what you find and we can troubleshoot backwards from there

I took these voltages with the key in the run position.

I’m Not interested in voltages on those wires as much as resistance (ohm) and continuity (connected at both ends.

The ground and power wires should show dang close to battery volt

 

[SKW1020]

Thank you so much, I'll do it this evening... thanks again!

I took these voltages with the key in the run position.

Ok, now this is crazy..... Checking for continuity between pin 15 and 16 with SCP Bus + and - Key on and Key off, I got NO continuity. Again, checking for continuity between pin 24, 25, 51, and 103: Yes
For pin 71 as well as 97, I got nothing... and these last two were different than the others in that I couldn't feel any resistance when I pushed my lead into the hole, like there was nothing inside either 71 or 97. What do you make of all that?

 

[SKW1020]

Thank you so much, I'll do it this evening... thanks again!

Ok, now this is crazy..... Checking for continuity between pin 15 and 16 with SCP Bus + and - Key on and Key off, I got NO continuity. Again, checking for continuity between pin 24, 25, 51, and 103: Yes
For pin 71 as well as 97, I got nothing... and these last two were different than the others in that I couldn't feel any resistance when I pushed my lead into the hole, like there was nothing inside either 71 or 97. What do you make of all that?

I misspoke about pins 24, 25, 51 and 103... I tested them for ground at least I think thats what I did..... I put a lead into the pin # and the other to a ground on the chassis... with my meter set to continuity. I'm not sure how you verify a ground, so let me know if I did that right.

 

[SKW1020]

I misspoke about pins 24, 25, 51 and 103... I tested them for ground at least I think thats what I did..... I put a lead into the pin # and the other to a ground on the chassis... with my meter set to continuity. I'm not sure how you verify a ground, so let me know if I did that right.

And when I checked pin 55 for voltage, it showed like 4 milliamps, key off. I am not sure I am doing these tests correctly.

 

[410Fortune]

Continuity test
Your
Multimeter will give a tone or “return to zero” when you touch the two leads together

So what you want to do is run a long jumper wire from the obd2 port all the way to the pcm
And check that the scp bus wires have continuity to their “other end” at the pcm
Do this for both wires
Pin 2 at one 2 connector (bus+) all the way to pin 16 at the PCM (bus +)
And repeat for bus -

Sounds like you did a solid “ continuity to ground” test already

Voltages on these tests should be 12.0v or near battery power, not “millivolts”

 

[Turdle]

Sorry for butting in, but, I sure do hope all fuses have been checked.

 

[SKW1020]

Sorry for butting in, but, I sure do hope all fuses have been checked.

they have, and butt in anytime lol...

 

[410Fortune]

The more minds we get In here the better the chances of fixing his truck!!!

 

[SKW1020]

The more minds we get In here the better the chances of fixing his truck!!!

So if I have no continuity between pin 15, 16 and the scp bus + & - what does that say about things?

 

[410Fortune]

Now you need to find out why
Somewhere between the dash and the pcm wires are not connected

As I said before they pass through the 3 bulkhead connectors under your brake booster and then travel over to the 42 pin square connector c115 and then finally to tbr pcm

You need to inspect the wiring along this path
I would start with the c115 connector because it is easiest to access

Pins 3 and 11 are circuits 914 and 915, the can bus + and - wires

Testing at this plug you can determine is the break is between the dash and c115 or pcm and c115… (where to look next)

 

[SKW1020]

Now you need to find out why
Somewhere between the dash and the pcm wires are not connected

As I said before they pass through the 3 bulkhead connectors under your brake booster and then travel over to the 42 pin square connector c115 and then finally to tbr pcm

You need to inspect the wiring along this path
I would start with the c115 connector because it is easiest to access

Pins 3 and 11 are circuits 914 and 915, the can bus + and - wires

Testing at this plug you can determine is the break is between the dash and c115 or pcm and c115… (where to look next)

Ok, so when I'm looking at the c115 plug, I only find the pin 16 which is circuit 914 on the PCM. Any reason I can't find the pin 15 circuit 915?

 

[410Fortune]

Ummmm
At the obd2 connector circuits 914 and 915
Are on pins 2 and 10

At c115 they are pins 3 and 11

At the pcm they are
Pins 15 and 16

Their circuit numbers are 914 and 915
Colors are tan w orange and pink with light blue

 

[SKW1020]

Ummmm
At the obd2 connector circuits 914 and 915
Are on pins 2 and 10

At c115 they are pins 3 and 11

At the pcm they are
Pins 15 and 16

Their circuit numbers are 914 and 915
Colors are tan w orange and pink with light blue

View attachment 463226

Well, I must be looking at diagrams of some other vehicle... that has to be whats going on here..lol.... I feel your response lol.... I mean, nothing like living up to Arkansas' reputation lol. I'll follow your info instead of mine, thanks!

 

[410Fortune]

Omg this is a sport trac
Hang tight I’ve been using the book for a 2000 explorer

Let me go get my sport trac book
My bad
I get my threads crossed from time to time

 

[410Fortune]

Try again 2001 sport trac
C110 (42 pin plug)

Still pins 3 and 11
Obd2 ports are all the same
And pcm is same pins 15 and 16

 

[410Fortune]

PCM still pins 15 and 16

View attachment 463234

 

[SKW1020]

Try again 2001 sport trac
C110 (42 pin plug)

View attachment 463232

Still pins 3 and 11
Obd2 ports are all the same
And pcm is same pins 15 and 16

At least youre honest! Thanks for redeeming me!

 

[SKW1020]

At least youre honest! Thanks for redeeming me!

And I am assuming that I test the obd2 with the male side of the 42 connector and that I test the pcm with the female side of the 42 pin connector...

 

[410Fortune]

I’d have to go outside and take one apart but I can show you it’s pretty obvious pcm side and dash/ truck side