I keep getting the same two (2) codes.

P 1395 GP Monitor Fault BANK #1

p 1396 GP Monitor Fault Bank #2

I just changed all GP's last week as I was just getting one of those codes. (don't recall which bank) I tested the GP's through the connectors and found GP's on both banks nearest the fire wall to be bad.

I bought four new harnesses and pulled the little SOB apart and replaced all GP's, after installation I again checked each GP.

I did not check the harness again (stupid) as they all looked good visually and I put it all back together and I again checked the GP's through the connecters, all were well.

When I started the truck that is when I pulled both codes.

In the mean time the dealer changed my CPS via the recall. I have just now finished pulling the passenger VC as well as the harnesses. I cleaned them off with compressed air and they all checked out good. I also checked the pins in the VC gasket and they all check good.

I also double checked the newly installed GP's and they are good. I just know if I pull the driver's side VC that everthing there is going to check out as well.

QUESTION

How do I check the harness that plugs into the VC connecters? I don't even know where this harness goes. I sure that it is something other than the UVC that is causing the problems.

I have in the past cleared these codes and the rig runs great and as long as it is hot (Warmed up) and I stop and restart the tngine I wont get a CEL
Let it cool and BINGO, I get both codes again.

I have checked the GPR the best that I know how and everything seems to be getting the proper voltage with and without the ign. being on.

I'm fairly convinced that the problem lays within the large harness on top of the engine.

I supposed as long as i have new harnesses I might as well chang them as preventive maintenance.

The truck runs too damn good to be having these kinds of problems.

All thoughts and suggestions are always welcome.

Roger

 

Have you tested to make sure the relay is actually transfering voltage to the glow plugs. with key on (for normal glow plug time) both large studs should have power.

 

I just checked again. I had voltage to the stud W/O the shunt. Turned the ign. on and I got 12V on the shunt side.

In fact I kept my meter on the big terminal that has the shunt strap that goes to two other studs and after a considerable time I heard and felt the relay click and the shunt stud started to lose voltage at a rapid pace.

The part that bothers me is that I was on top of that engine so much when I was replacing the fuel pump and the turbo I could have smooched most anything, and there sure is a lot of crap up there.

Remember I only had this code on one side until I changed all of the GP's

Rog

 

TJ:
On the pass. side of the fuel filter there is a plug of sorts and held to the fuel bowel with a single screw. There is a connection of harnesses from both ends of this unit. Do you know what it's purpose in life is?
Rog

 

Yes that is the pigtail that the fuel filter wiring and IPR harness plug into.

 

TJ:

The harness plug pins that plug into the VC Recepticals are numbered

1-2-3-4-5 1 & 5 give power to the GP's

2 & 4 give power to the Injectors

3 is a common ground for 2 & 4

Using a test lite and with the Ign. ON I should have power to 1-2-4 & 5 do you agree with this?

QUESTION:

There isn't more than 12 Volts going to GP's or the Inj's are there, maybe through a system that I don't know about?

Rog

 

You should have battery voltage to the GP but not the injectors with the key on and relay on.
The injectors get power from the IDM only after the engine is cranking and its near 100 volts

 

Rog

Check the connections and wires on the shunt.
The wires on the outer ends are the feeds for the gp's and the PCM monitor. (Lt/Rt banks)
The monitor senses off of the shunt.
Right Bank--Br=gp, Or=monitor
Left Bank --Ye=gp, Pk/or=monitor

Bill

 

OK, sense I only have a GP problem we can eliminate pins 2-3-4 so 1 & 5
should be hot with the ign on.

For some odd reason I'm not doubting that they will be hot.

Well something for sure is causing this/

Rog

 

Bill is the guy we need here! thanks Bill! I have no clue what the CA models are all about with the GP garbage!

 

Tim

Its the same system. Just has an extra.
The GPR has a shunt bar on the load side to split the gp system in right and left banks. At the split there is a wire L&R bank for input to the PCM.
All it does is compare voltage drops right/left.

Bill

 

Got any pics?

 

Where is Rick when you need him!

?

Bill

 

I 2X Tim, thanks for jumping in Bill. Now what kind of voltage should I expect on the ends of the shunt? I would suspect that it should be close as the voltage that feeds the shunt.

Do these shunts go bad to the point that they don't carry voltage the same?

There are also two (2) smaller terminals. What do they feed?

Rog

 

Have not seen a shunt go bad.
That bar gets hot enough that it will burn you.
Have seen the connections and wires to the shunt go bad.(heat)
Just remove/clean reconnect the rt/lt bank connections.

Bill