I have been living with this for so long I can't even find the original thread so I'll give ya a Reader's Digest version.

Cold start up, 30 seconds later get CEL: P-1395, P-1396 translation, GP Monitor Fault Bank #1 & #2. Clear codes and can run the rest of the day many starts & stops...No Codes. Go home and check w/reader and there they are laying dormant.


REPLACED To Date:
All GP's, (2 dead) Both UVC Gaskets,(1 burned contact) All 4 UVC Harnesses,(Grasping at straws) Replaced GPR.(Ford wouldn't take it back) I had found a UVCG plug w/one burned contact.

I have cleaned and polished all connections and I still get a CEL at cold start, clear it and I'm good for the rest of the day.

A non member from another forum told me that these codes are associated with Cali trucks and if I had less than 36 or 38 (Can't recall exactly) AMPS going to any one bank they would trip those codes. I didn't know what he meant and have not as yet received a reply from him.

Now the strange part:

My truck has set forr 2-3 days, I went out and started it up cold, 30 seconds later I get a CEL I let the truck warm for about 5 Mins. Turn it off and take a code reading and get: P-1395, P-1396 and two (2) more codes that I have never had: P-1391 & P-1393 which are:
GP Ciruit Low Input Bank #1 (RH) & Bank #2 (LH)

I don't know what these mean, I do not know how or where to look to check where the low input would be and I don't know where to look or check for a drop in the AMPS going to either Bank.

Does anyone have a clue as to what I am talking about??

I have checked voltage going to and from the GPR and that checks OK.
I have not check the AMPS going to and from the GPR. I now have that instrument and will do so tomorrow.

Any and all help is appreciated.

Roger

 

WOW I feel your pain. Just takin' a stab in the dark...Have you checked all grounds? I mean it sounds like a groundprob in the GP circuit somewhere. Like I said just a stab in the dark.

 

The alternator is the only thing I can think of that produces amps, high or low. If the alternator isn't working properly, that could be causing a low-amp reading.

That's my stab in the dark.

 

Another stab in the dark ... I noticed on the engine diagram 97 Cali trucks, except for the Super Duty also have fuse links in GP circuit, between the GPR and the GP's. Don't know where in the wire bundle they are located though.

 

I don't recall the exact number but there are 4-5 fuse links associated with the GPR and I have checked these both physically and with a meter. All are well and working.
Rog

 

Thanks.....but the ALT is up and running strong.
Rog

 

Thanks Neal....but I have checked all of the grounds as well as any type of connection that I run across.

This is more frustrating than multiple wives, Not that I have first hand knowledge of that.

Rog

 

Are the batteries OK? I would have them load tested...just a thought...if they are maybe take off the battery cables and clean them along with the battery posts and check the connections at the starter relay...make sure there clean and tight.
--------------Jeremy

 

[QUOTE=jboard]Are the batteries OK? I would have them load tested...just a thought...if they are maybe take off the battery cables and clean them along with the battery posts and check the connections at the starter relay...make sure there clean and tight.
--------------Jeremy[/QUOTE

Thanks jboard, Both batteries top of the line both changed at same time less than 2 months ago.
Rog

 

If it is a Cali truck there is a resistor on 2 terminals of the GP relay have it tested.

 

Dinikin: I'm assumeing that these resisters are not located inside the GPR. I know of the "Fuse Links" inline. Where are these resisters located? If you know.

I really want to get this repaired as I don't want to start the New Year with the same problem that I ended it with.

Rog

 

Roger I want to let you know I am onboard with this one but still trying to figure out what the problem might be! Maybe a resistor needs to be added to trick the PCM! LOL

 

Thank you TJ and Happy New Year!

Roger

 

Man, I'm an idiot. I just typed up a 500 word reply, then realized I missed something that was posted above.
Try this- you might need to pull the valve covers.

You need an inductive DC ammeter, it clamps around the wire and takes an amperage reading without breaking the circuit, It's almost the greatest thing ever made, Remember, DC not AC.

Put the meter around a wire that goes to a glow plug and then turn your key on. Record the reading and turn the key off.

Go to each glow plug wire and repeat this.

Hopefully you will have a place in the harness that you can get the clamp around the wire, if not you will need to read the GP wires on the UVC.

You will probably have some readings that are lower than the others. Those are going to be the problem children. I'll bet that the fusible links going to them have a problem.

To verify that, go back to the lowest readings, and run a known good jumper wire from the GPR terminal that is not always on. disconnect the UVC lead at the glow plug and connect the jumper wire to the GP terminal.

If your amp reading goes up, you have a bad wire, conection, or fusible link between the GP and the GPR for that particular GP.

If your amp reading does not go up, then that wire is good, and you need to look at the feed that goes to the GPR. It also should have some form of fusing such as a fusible link.

If all the GP's read the same then the problem will be something they all have in common, most likely the main feed coming in to the GPR, or the circuit in the PCM that reads the GP amperage.

This is kind of the backwards way to test it, normally I would verify the main power to the GPR first, especially since the problem affects both banks, but I am betting that you checked that properly already.

The only other element would be to find out how the computer senses the amp draw from the GP circuit and verify that circuit is working properly. I don't have any technical resources here for that, but if anyone can find that info, I'll be happy to try to figure it out.

I doubt that it is a ground propblem, but I could be wrong. The GP's ground directly to the engine, just like the starter. If the ground was too bad for the GP's to work, the starter probably wouldn't either.

Good luck with it and let us know what you find.

 

Hey kawa,

When did this problem start?

Vince