I have a California 1999 SD F-350 7.3 PSD, produced in 12/98. I am getting the code above, indicating a glow plug monitor fault bank 2. We pulled the valve cover and replace the harness, but it still codes. The dealer is telling me I need a $790.00 replacement part, he called it the glow plug module. This sounds real crazy to me...Any suggestions? BTW, the truck starts and runs fine, it just has the dashboard SES light on all the time...

 

There you have it. No rush for the expensive GPC that you do have. I have not looked up the code but feel you may simply have one or two bad GPs. Someone else will be along with the code info I am sure. Might want to ohm out the GPs at the harness or try a telt light. It is simply telling you something on one side is failing. It cannot tell you which one.

 

KC1 DTC P1391 AND P1395 RIGHT BANK, P1393 AND P1396 LEFT BANK AND P1994 CENTER MONITORING CIRCUIT

• Note: The glow plug system is monitored when the glow plugs are commanded on for more than 35 seconds and battery voltage is between 11.5-14 volts.
  
  DTC P1395 or P1396 will set on the bank that is reading less than 39 amps. Loose fitting pins in the circuit connectors causing high resistance or high-resistance glow plug(s) on that bank could be the cause. A shorted circuit or low-resistance glow plug(s) on the opposite bank could also be the cause. Each bank needs to draw more than 39 amps.
  
  DTC P1391 or P1393 will set when the monitor indicates that all four glow plugs are not being powered on that bank. An open in the glow plug circuits, glow plug relay, glow plugs or monitoring circuit could be the possible causes.
  
  Both DTCs P1391 and P1393 together will set when the monitor indicates that all eight glow plugs are not being powered. An open in all glow plug circuits, the glow plug relay, glow plugs, fusible links or all three monitoring circuits could be the possible causes.
• Possible causes:
  • glow plug relay
  • glow plug shunt
  • open in glow plug circuit(s) or monitoring circuit(s)
  • glow plugs
  • PCM

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I would have put in a set of glow plugs, even if they ohmed out OK.
I get this all the time on TDI's.
Replace all the glow plugs and the problem goes away. Sometimes it requires a new harness as well, but only 1 in 100. It's always the glow plugs.

 

https://www.ford-trucks.com/forums/7...-code-gpr.html

 

I'm getting p1395-6 reading on my1999 F-350 runs fine SES light on

 

Strider1,

Your code is saying you are having some problem with the glow plugs. Unless your in very cold temperatures you really don't need glow plugs to start. If you go somewhere where it is cold you may find you need those glow plugs to work.

At the top of this forum are some sticky's that can help explain how to check the glow plugs and related parts.

I hope I am not telling you what you already know. I am not sure if your post is a question.

 

White 99,

Hi there and thanks for the info, and yes it was a question. next is any info on the GP module? if I replace it will that cure the code and allow the SES light to go away.

Thanks Again

 

You need to determine if you have a glow plug control module or a glow plug relay with a shunt. Here are a couple of pics that should help you figure out what you have:

Ford Truck Enthusiasts Forums - tdpower's Album: Useful pics - Picture

Ford Truck Enthusiasts Forums - tdpower's Album: Useful pics - Picture

You probably have a gpr with a shunt. I would start by testing the gpr then ohm the glow plugs at the valve cover 9 pin connection.

 

True the relay is what i have, thanks for the input I will check it after work

 

Strider1

I assume you have an 99 model I am not sure exactly what date they switched to the Glow Pulg Control Module. If you have a volt meter the Glow Plug Relay is not hard to check. With a cold engine the relay should stay engaged for a minute or so. While it is engaged you should see close to the same voltage on both big lugs, a little less on the glow plug side. Watch out for the thin metal band that goes from the switched side it gets hot.

If relay checks out you just need to follow the system down to the glow plugs checking for problems. You will need an continuity checker/owm meter for that. Let us know what you find. If you have a AutoEnginuity scan tool you can watch the amperage the glow plugs draw.

I have been fooling around with mine throwing p1395 and p1396.

 

Hello, I am new to ford-trucks.com after having the same problem as Strider1. I have tested the GPR and it seems to be okay but has 2-3 volts lower on the glowplug side when the key is turned on, is this normal? Also, my truck starts okay, maybe a little longer cranking (10 secs or so) then before the code but it is colder now. Could a bad shunt be the cause? Should I check the voltage on each side of the GPR to determine if the voltage is the same? I have ohm tested most all the glow plugs at the harness and have 0 ohms. Any suggestions for further analysis?
Thanks

 

Hello BVSRetired,

Let me see if I can help. Are you throwing the 1395/6 code?
Any other symptoms?

I think 2 or 3 volts lower on the glow plug side of the relay is a little much. I drop to 11.5 or so from 12.4 or so. I don't think the truck will start with voltage below 10v or maybe it is 10.5 volts while cranking. With the glow plugs on and the starter engaged on my truck the voltage drops to the 10.something range.

 

P1395 is the code it's throwing. No other syptoms. The check engine lights comes on right after the "Wait to Start" light turns off. Could it be a weak GPR, I have never changed it out and have owned the truck since new?
Thank you very much for helping!!

 

How are you checking the codes? Do you maybe have a AutoEnginuty?

It gets cold in your part of Calif doesn't it; does the engine start OK when cold or does it blow white smoke when starting? The reason I am asking is on mine I get the code but the glow plugs are working fine.

We could be having the same problem and if so I will gladly tell you what I have done.