Ok could still use a bit of help from you guys....

[GTA_V6_Mustang]

Ok well I am sure some of you know of the problem I am having... So I need some input, When I turn the key to ignition it starts the diagnostic mode. If I let it complete I can start the car and no KOER test will happen. I opened the harness to the DLC into the fenderwell and its fine. I took a voltmeter and the wire that is alone has 4.88V if i remembered correctly and the other has none with the KOEO. So I tried putting the key to ignition and it did it of course. I yank on the harness underhood and at the PCM and nothing it stays like that. However if i have the jumper wire hooked up and it goes starts the process and I yank out the jumper wire it kills diagnostic mode. However after I let the car sit for a bit off. And get back in it goes right back into diagnostic mode.... Any ideas? Maybe I need a new pcm Any help is greatly appreciated.

 

[HISSIN50]

The single DLC should be the self test input (white/pink) and is pin 48 at the EEC. I'd disconnect the EEC harness and ohm out each end of the wire. If there are doubts, consider running a new wire. I hate cutting OEM harness wires but it can be easier than finding a short via wiggle testing. I suppose you could use a toggle switch near the EEC end of the wire to interrupt the signal. Or if you have neato short-finders (like I've seen in the airplane industry, for one), that could really help.

You very well could be right in that the puter ate crap. I cant remember if the STI circuit floats voltage at rest or not. I dont think it does (or is supposed to). I would have have expected to see it float VRef anyways (I'd expect VPWR).

Your observations about interrupting the codes and having it not act up until you turn the key off and on are normal. The puter uses an accessory-power interurupt.

 

[GTA_V6_Mustang]

The single DLC should be the self test input (white/pink) and is pin 48 at the EEC. I'd disconnect the EEC harness and ohm out each end of the wire. If there are doubts, consider running a new wire. I hate cutting OEM harness wires but it can be easier than finding a short via wiggle testing. I suppose you could use a toggle switch near the EEC end of the wire to interrupt the signal. Or if you have neato short-finders (like I've seen in the airplane industry, for one), that could really help.

You very well could be right in that the puter ate crap. I cant remember if the STI circuit floats voltage at rest or not. I dont think it does (or is supposed to). I would have have expected to see it float VRef anyways (I'd expect VPWR).

Your observations about interrupting the codes and having it not act up until you turn the key off and on are normal. The puter uses an accessory-power interurupt.

Ok kewl. Now on another thing, just to be sure I am in the right area. The PCM is the there on the passenger side foot area to the right correct? It is covered by 3 connectors and has 1 connector to it that has like a 10mm i believe bolting the connector to the PCM?

 

[HISSIN50]

You've got the right location for the EEC. I took a tip from Wes and just move the smaller connectors aside (leaving them connected). Then I can unbolt the main connector and remove the EEC. Install is reverse of removal.