Glow plug/pcm issues
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Glow plug/pcm issues
K guys I am new here, but here we go....I have read other threads regarding these issues, but here is my issue. 1997 F250 7.3 Power Stroke. Engine light on for unknown years, belonged to my wife before I met her. I knew the glow plugs were not working properly, had them eventually replaced along with the wiring harnesses by a very qualified shop.
Work performed: "Recheck connectors and found vehicle fails glow plug test. Found glow plugs drawing 75 amps per side when vehicle was left in shop over night ok. Performed pinpoint test. Tests all wires going to PCM for glow plug relay ok. Has internal problem Glow plug system working fine just check engine light on due to PCM problem."
So I did some research on what to do and Riebies (Napa auto) said they could send PCM out for a $150- to get it fixed. Got it back installed it (with batteries disconnected) and came up with same code, P1395 & P1396. They sent it out again (on warranty), three weeks later came back, installed again and came up with code again.
Ok, most of us probably really don't care if the light is on all the time, however I look at this way, how are you suppose to know if something else is going wrong if its on all the time. I am at a loss and VERY frustrated, any thoughts?
Work performed: "Recheck connectors and found vehicle fails glow plug test. Found glow plugs drawing 75 amps per side when vehicle was left in shop over night ok. Performed pinpoint test. Tests all wires going to PCM for glow plug relay ok. Has internal problem Glow plug system working fine just check engine light on due to PCM problem."
So I did some research on what to do and Riebies (Napa auto) said they could send PCM out for a $150- to get it fixed. Got it back installed it (with batteries disconnected) and came up with same code, P1395 & P1396. They sent it out again (on warranty), three weeks later came back, installed again and came up with code again.
Ok, most of us probably really don't care if the light is on all the time, however I look at this way, how are you suppose to know if something else is going wrong if its on all the time. I am at a loss and VERY frustrated, any thoughts?
Postmaster
Joined: Sep 2007
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From: Medford Oregon
This must be a Cali truck. It has always been an issue for their emissions and I don't know of a fix, maybe someone else does. Seems like the code is hard-coded in the PCM and can't be erased, don't know.
I believe the specs for each bank for glow plugs is 32 amps +- 8 amps, before Cali trucks threw the code. That said you are reporting 72 amps per bank. Have you replaced the glow plugs?
I believe the specs for each bank for glow plugs is 32 amps +- 8 amps, before Cali trucks threw the code. That said you are reporting 72 amps per bank. Have you replaced the glow plugs?
Cargo Master
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Ford can "re flash your PCM" to the tune of $100-$150 or so with no guarantee of success. P1396 gets burned into the PCM some how on these Cali trucks. Mine has had that CEL despite new GPS, and a Stancor GPR. I'm sure as heck not gonna waste $150 at Ford to have a CEL removed.
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Yes this is cali. truck. The glow plugs, and wiring harnesses all have been replaced and checked with ford parts. All done by a Ford Diesel specialist shop and mechanic. Like I said in the beginning I don't care if the light is on, however it would be nice to fix it, do to the fact we want to make this truck to last a life time and how are you going to know if there is another problem? Since I have been trying to fix it up so it will.
Cargo Master
Joined: Nov 2010
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Yes this is cali. truck. The glow plugs, and wiring harnesses all have been replaced and checked with ford parts. All done by a Ford Diesel specialist shop and mechanic. Like I said in the beginning I don't care if the light is on, however it would be nice to fix it, do to the fact we want to make this truck to last a life time and how are you going to know if there is another problem? Since I have been trying to fix it up so it will.
There is no problem. But if you want further reading on this burn to PCM issue check out Ford TSB# 98-15-1.
Postmaster
Joined: Nov 2005
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From: San Ramon Ca.
First off make sure the GPR is really good. Check the voltage drop across the relay. If its close to a volt, more or less, replace the relay. Don't use a Napa relay they are junk. I have a Delphi relay in mine now. No more codes that pop the check engine light. Starts better too.
On edit: You might want to check the cable / connection that feeds the GPR from the starter relay.
On edit: You might want to check the cable / connection that feeds the GPR from the starter relay.
Postmaster
Joined: Sep 2007
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From: Medford Oregon
Here is some info that may, or may not help ... 
Typical Glow Plug Monitor Entry Conditions:
P1391 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts and Glow Plug Duty Cycle is 100%.
P1393 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts and Glow Plug Duty Cycle is 100%.
P1395 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts, Glow Plug Duty Cycle is 100%, and Glow
Plug on time is greater than 30.5 seconds.
P1396 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts, Glow Plug Duty Cycle is 100%, and Glow
Plug on time is greater than 30.5 seconds.
Typical Glow Plug Monitor Malfunction Thresholds:
P1391 – When the Bank #1 shunt signal is lower than a specified value (.66 volts) the fault is set.
P1393 – When the Bank #2 shunt signal is lower than a specified value (.66 volts) the fault is set.
P1395 – During the absolute test a fault is set if the voltage drops below a specified value (155 A/D counts)
on Bank #1.
P1396 – During the absolute test a fault is set if the voltage drops below a specified value (155 A/D counts)
on Bank #2.
Your error code 1395 and 1396 is indicating that the voltage, at the relay, is dropping below the minimum threshold of 11.5 volts. At least that is the way I'm reading the information. Easy enough to measure to verify though.
Typical Glow Plug Monitor Entry Conditions:
P1391 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts and Glow Plug Duty Cycle is 100%.
P1393 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts and Glow Plug Duty Cycle is 100%.
P1395 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts, Glow Plug Duty Cycle is 100%, and Glow
Plug on time is greater than 30.5 seconds.
P1396 – Battery Voltage (IVPWR) is between 11.5 and 14 Volts, Glow Plug Duty Cycle is 100%, and Glow
Plug on time is greater than 30.5 seconds.
Typical Glow Plug Monitor Malfunction Thresholds:
P1391 – When the Bank #1 shunt signal is lower than a specified value (.66 volts) the fault is set.
P1393 – When the Bank #2 shunt signal is lower than a specified value (.66 volts) the fault is set.
P1395 – During the absolute test a fault is set if the voltage drops below a specified value (155 A/D counts)
on Bank #1.
P1396 – During the absolute test a fault is set if the voltage drops below a specified value (155 A/D counts)
on Bank #2.
Your error code 1395 and 1396 is indicating that the voltage, at the relay, is dropping below the minimum threshold of 11.5 volts. At least that is the way I'm reading the information. Easy enough to measure to verify though.