Pats Question

IH8BOWTIES · Apr 25, 2017

I have a 2000 that I recently put a new engine in but fuel pump wasn't priming. Checking for voltage at the FPDM, the PATS came on after a few times of turning the key on and off. I'm suspecting the key or transceiver. I'm getting 12 volts at all power inputs to the pcm except pin 97. Does anyone know what signals power to pin 97 or in my case doesn't? It was proving out with no issues. The car sat for a year or so. I don't know if all the turning of the key off and on could have had an effect on it. Any help is appreciated.

wmburns · Apr 26, 2017

Ford Factory PATS works by withholding fuel injector pulse. PATS does NOT withhold power from from the fuel pump. So if the fuel pump does not prime, this is not a PATS problem.

NOTE! a no PCM power issue will at first glance appear to be a PATS problem. Remember that the cluster and PCM need to "talk" to each other to clear PATS. So if either the cluster or PCM isn't working, THEN it would be expected that PATS wouldn't "prove out".

PCM pin #97 is powered via fuse F2.2. Sooooooooooo if no power to PCM #97 means:

Blown F2.2 fuse (or other blown fuse).
CCRM "issue".
bad ignition switch
wiring or ground fault.

Considering the amount of work done the first thing I would recommend is checking the CCRM/PCM ground. This is a larger black wire with a white stripe that goes from the radiator core support around the battery. It connects to a larger round single pin connector. It's easier to find with the battery removed.

Double check all of the grounds around the radiator core support. Are they clean and tight?

Next Test for key on power to fuse F2.2, F2.8, F2.21, F2.34. The combination of which fuses with power and which don't provide clues where to focus next.

IF no power to fuse F2.34 focus on an ignition switch problem.

IF no power to fuse F2.2 and F2.8, focus on a CCRM "issue" including a bad CCRM ground. Additional test of the CCRM may be needed to narrow focus.

1999-2004 MY fuse panel schedule:
http://www.allfordmustangs.com/foru...r-swap-wont-fire-please-help.html#post2669271

1996+ Crank with no start check list
http://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html#2984838

IH8BOWTIES · Apr 26, 2017

Thank you WM. I did check the fuses but I did not check the power to them. I'll give that a shot. The ground at the core support is good. When I first put a battery in it, it did the same thing and I remembered that ground. Hooked it up and it started working. Now it's back to the same thing. Thanks for your help.

IH8BOWTIES · Apr 29, 2017

Checked power to all fuses you mentioned. They all have power. All of the ground wires are solid with good connection.

wmburns · Apr 29, 2017

Well...........

IF fuse F2.2 has power in and out and PCM pin #97 does not THEN there's a broken wire between fuse F2.2 and PCM #97

I suggest that you go back and double check all work. Warning. Wild goose chase alert!

Does the theft light "prove out" at key on? (from the crank with no start check list)?

Is there power at the trunk IFS switch with the key on?

Test the RD wire at the MAF with the key on for +12 volts. This wire is also feed from F2.2.

IH8BOWTIES · Apr 29, 2017

There is 12 volts at the IFS and the MAF with key on. I will pull the connector tomorrow and do a continuity check between pin 97 and fuse f2.2. There is also a connector just under the BJB with two wires that runs to neg battery terminal. One is Black/white and the other is Black/yellow and they run into the harness that runs under the battery tray. The black/yellow has no continuity. I don't know what that goes to. Seems if its a ground, it should have continuity between the connector and any ground point. The theft light does not prove out. It just keeps flashing and the rad fan comes on. (That should mean the CCRM is good right?)

wmburns · Apr 30, 2017

IH8BOWTIES said:
The theft light does not prove out. It just keeps flashing and the rad fan comes on.

Note, the cooling fan running all the time often means that the PCM is not powered or dead. Which makes sense if PCM #97 does not have power then the PCM isn't getting power or is dead. Might be a good idea to test PCM#71 (RD) should also have +12 volts with the key on.

Note2, IF the PCM is dead, THEN it would be expected that PATS will not prove out. PLUS the fuel pump won't run!

IH8BOWTIES said:
(That should mean the CCRM is good right?)

Yes it means that the low speed cooling fan part of the CCRM is working. Also the fact that fuse F2.2 has power also means that the CCRM is working.

It seems to me that the base problem is PCM power related. Everything else is a symptom of the PCM not working.

IH8BOWTIES · Apr 30, 2017

Well, I started to do a continuity check on pin 97 to f2.2 and decided to do a voltage check again thinking maybe I forgot to connect everything back up gaining access to the pcm. I guess that was the case. I'm getting 12v to everything now. Guess my pcm is toast.

IH8BOWTIES · Apr 30, 2017

I hooked everything back up and still the same. I did,however, leave the key on for a couple of minutes and the theft light started flashing one time, then six times and kept repeating. Is that telling me something?

wmburns · Apr 30, 2017

I would CONFIRM all the grounds with a voltage drop test from the PCM back to battery negative before calling the PCM. Especially since it worked before the motor swap. There are several PCM grounding terminals.

There are two main grounds that "could" be "over looked" after a motor swap. One is near the battery. The other is below the air filter (remove for better access).

Double check the grounding strap from the left hand motor mount to the frame rail.

G201 PCM pin #25. Black
G104 PCM pin 3, 51, 77,103 Black/white stripe

EDIT: IF the PCM grounds are no good is it possible that when the voltage test for pin #97 was done one of the PCM grounds were used? If so this creates the possibility that is the reason why you thought #97 did not have power.

IH8BOWTIES · May 14, 2017

I did check continuity at all grounds from the pcm connector. They were all good. A friend has one out of a 5 speed car. I know my car won't run with it but if I hook it up and it powers up, at least that would lead me a little closer to calling the pcm.

Jaime Tucjer · Sep 4, 2017

so you ever find out what it was im having a similar problems

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