2004 Ranger no communication with ecm

[jalex2001]

No crank no start Ford issues are pretty easy to diagnose. Click on the illustration below and download the PDF wiring diagram of a typical Ford starting system. You’ll see that the system consists of a fuse, ignition switch, starter relay, transmission range selector (neutral safety switch on for an automatic transmission) or a start inhibit switch for a manual transmission, and a ground control circuit provided by the PCM. The PCM gets involved here because of the ford passive anti-theft system (PATS). The PATS system must see the correct key in the ignition switch before it will provide ground to the starter relay. I’ve listed all the areas for your to test for power and ground. Good luck. And don’t forget to clean all the ground points, a corroded ground can really cause problems with these starting circuits.
Just cant find the down load/PDF to this article !!!!!
@ShhhhhDougsHere

 

[ShhhhhDougsHere]

So what you just posted is a copy and paste?

 

[jalex2001]

ford passive anti-theft system (PATS). The PATS system must see the correct key in the ignition switch before it will provide ground to the starter relay. I’ve listed all the areas for your to test for power and ground. Good luck. And don’t forget to clean all the ground points, a corroded ground can really cause problems with these starting circuits.

So what you just posted is a copy and paste?

Thats what i was reading about the Pats

 

[ShhhhhDougsHere]

Is this what you can't find?

Or have you seen that?

 

[jalex2001]

Is this what you can't find?

View attachment 133414

Or have you seen that?

Yes i saw this

 

[ShhhhhDougsHere]

So what I'm seeing in the diagram,

Power goes from the battery to the relay.
And when the ignition is switch to the start position power goes from the ignition to the starter relay and then on to the PCM.
The PCM uses it's own ground to magnetized the filament inside the relay which then switches the relay into start mode.
At that point with the relay magnetized the relay clicks the internal arm from the dead pin to the start pin that goes to the starter.
And the truck should start.

Is that how you read it as well?

 

[ShhhhhDougsHere]

Have a brown wire that is 12v yellow to starter. Then 2 18 gauge wires yellow w/red and blk/red that dont seem to do anything. Ive applied 12v to each with power probe and checked them for ground.

Big fingers posted this before I was done.

I think your ( yellow with red stripe ) wire is your ignition wire.

That would leave the black with the red stripe going to the PCM.

Does it seem right to you?

 

[ShhhhhDougsHere]

I edited my last post in this thread please reread.

 

[ShhhhhDougsHere]

Are you still with me here @jalex2001.

Can you hook 1 end of your probe to a ground.
And put the other end into the wire clip for the yellow wire with the red stripe were the relay plugs in?

Then turn the key to the start position and see if that wire send out power when the key is in the start position?

If it doesn't.
Then try the test with black wire with the red stripe and see if it puts out power when the key is in the start position?

If you've already tried this let me know that thanks.

 

[Curious Hound]

This thread is a mess. Jalex, do you get 12 volts on the starter relay terminal that is fed from the key switch in the start position? If so, the key switch part of the circuit is good.

Next. If you disconnect the pcm wire from the starter relay and short that terminal to ground, will the starter run with the key in the start position? If it will, then this proves the starter relay is good and the issue is with the PCM not grou ding the relay for some reason. At that point, we need to find out why the PCM will not allow a start. That will probably require some other wiring diagrams.

Doug, the starter relay is not usually a "plug-in" style relay because of the high current it must pass to the starter. You can stop referring to it this way. The terminals are different. It works the same way. But it is a larger, more heavy duty relay.

 

[ShhhhhDougsHere]

Thank you very much @Curious Hound for stepping in to this thread and helping out.

Thank you even more for correcting me when I'm wrong about something.
I will stop referring to the starter relay as if it is a plug-in relay.