Circuit Error on PCM

Hey All,

I'm new here and came to know about the site from the youtube videos and though here is the only caliber of people that can help me.

Im having a 2008 Ford Explorer that i just did an engine swap for. the engine wiring harness was in a bad shape due to age, it had a 5v reference voltage error which was fixed. It also required a new ECU which was changed.

We are now getting a lot of circuit errors from various modules on the PCM, Many mechanics are clueless and i am slowly turning into a part changer. I dont have a wiring diagram and its really guess work now.

Attached are all the images from the Diag tools, if someone can please point me somewhere i'd appreciate it a lot.

I am from Dubai and the caliber here is not something that i can see it getting it fixed.

Thanks

Hey dusk1911, welcome! In situations like this, it can be beneficial to clear codes and see which comes come back first. Do all those codes come back immediately? Or do some come back sooner than others? From the codes that come back immediately, I'll usually pick the one that's most accessible and start my testing there.

You didn't say if this Exploder has the 4.0L or the 4.6L? It matters for the wiring diagrams. Which, BTW, you can find here for free

www.bbbind.com/free-tsb

Taking a quick look at the 4.0L diagram, I see that fuse #42 (15A) in the Battery Junction Box (underhood) powers the O2 heaters, purge valve, and EGR valve. If you haven't already, it'd be a good idea to verify that fuse with a test light. Maybe do the same for all other fuses while you're at it. :silly: Weird stuff happens when engines get swapped.

Let me know which codes come back first, and which engine you have.

HI
I see that you changed out PCM are you sure that its for your engine?
If so I would do as some one stated clear all codes and see what comes back. I have a feeling that you need to check all powers and grounds start at the PCM .
Next check to see if you have your ref vot +/- 5 vdc. If not un plug all that use that 5 vdc ref and check to see if your 5 vdc is there plug in one at a time and keep checking ref voltage. If you have that working You may have to re-flash the PCM

this is a good starting point good luck


Doc

Thanks for the response guys. Should have mentioned it's a 4.0L. The reference voltage error is fixed. It's now like there is something shorting the entire PCM circuit or at least whatever is on the errors. Unfortunately I am not good with these things but trying my best here.

So just to clarify .. if I test the modules on the 5V is that to tell me if there is a short on the PCM or where you referring the the short on the 5v ?

Btw all the errors come back at once not one by one.

I think you have a problem with the PCM . is it new and was it programmed?
Do you have your 5 volt ref ?
if so I would start looking at all grounds and powers to PCM .
re check your plug to the PCM make sure all the pins are ok.
Next I would be looking at the fuse box and harness.
Doc

dusk1911 wrote: Thanks for the response guys. Should have mentioned it's a 4.0L. The reference voltage error is fixed. It's now like there is something shorting the entire PCM circuit or at least whatever is on the errors.

Thanks for the clarification! I dunno that anything shorting anything out at this point? You need to start with voltage measurements at one of the outputs listed in your codes, or by checking that fuse I noted earlier.

Pick the easiest one to access and go from there. The EGR valve is right there on top.

yeah, thats exactly what im going to do today. Will keep you guys posted

So I checked some voltages and at the o2 it's .92 .. this lead me to think that the ECU is not flashed correctly. (I had a feeling the guy was dishonest) so I've put back the old ecu and I can communicate to it fine. But when I try to start the car the pats kick in and won't let me start the car. I have both the original keys, is there a way I can manually program the keys to the old ecu ?

Sorry for the stupid question but I've never flashed an ecu in my life but all I can do Is the old school way