Ok, I have searched for some info on the issue I am having with this code but cannot seem to find an answer. So, I am going to ask for some help.

I have a 1999 F350 with the 7.3 powerstroke and it is a CALI truck. Earlier this week the "service engine soon" light came on after a cold start (California cold that is). I went to my local AAMCO and they pulled the P1395 code which is for the glow plug bank #1. The tech erased the code and I went on my way to the parts store. Having done my research here, I removed and replaced the GPR (had noticed that it had been continuously clicking while waiting for glow plug light to go out) installing it exactly as it was prior to removing it.

The next morning (cold start) the SES light came back on. The truck runs no different with the light on or off (truck runs great) so what should I be looking for now?

Thank you all in advance for your thoughts and advice!

 

I thought all vehicles equipped for California emissions didn't have a GPR and were GPCM only? That's how the 7.3 in my Ex is, and all Excursions were Cali-compliant. The thing that looks like the GPR should be the AIH relay.

I have an intermittent CEL that I know is a few dead glow plugs between the two heads. Had codes pulled, ohm'd out through the UVCH as a quick double check and it confirmed. If the plugs don't cycle (warm engine, 165* IIRC) I don't get the CEL.

wood-n-things has some good info on his site. Operation principles and such https://b7445ba3-a-62cb3a1a-s-sites....edirects=2&d=1, and a write up of both the GPR and GPCM systems https://sites.google.com/site/woodnt...ow-plug-system

 

Welp, it definitely has a GPR so I'm guessing that the truck was originally NOT a California truck (I did buy it used so that is possible).

It is code P1395 so any ideas?

Thanks

 

Just to be 100% positive, there is no finned silver aluminum box with a green and black connector on the a passenger valve cover, inboard side? Tried attaching a pic but since I'm on my phone I don't know if it'll work properly.

I did find this entire write-up while poking around briefly on your issue... Not sure if it helps out or not,
This is from the manual: I don't know if it will help

S1 DTC P1391, P1395 — RIGHT BANK AND P1393, P1396 — LEFT BANK
Note: For running KOER glow plug monitoring self test, refer to Section 2C .
One of the above codes will set when glow plugs are commanded on for over 35 seconds and battery voltage is between 11.8v and 14v, with at least one glow plug not being powered.
Key off.
Measure voltage between large wire terminal Circuit 38 (BK/O) on glow plug relay and battery ground.
Is battery voltage present?
Yes No GO to S2 . SERVICE open in Circuit 38 (BK/O) or fusible links.
S2 CHECK FOR DTC P0380
NGS installed.
Perform KOEO On-Demand Self Test and Retrieve/Clear Continuous DTCs.
Is DTC P0380 present?
Yes No GO to S3 . GO to S8 .
S3 DTC P0380
DTC P0380 is set when the PCM detects a malfunction in the glow plug relay control circuit.
Possible causes:
shorted to power
open/grounded circuit
open fuse (F-Series — Fuse 22, Econoline — Fuse U)
worn or damaged glow plug relay
Key on, engine off.
Measure voltage at glow plug relay point B, Circuit 16 (R/LG) and battery ground. Refer to the schematic for location of circuits.
Is voltage present?
Yes No GO to S4 . SERVICE open in ignition power Circuit 16 (R/LG). If fuse is blown, CHECK for short to ground.
S4 RELAY COIL RESISTANCE TEST
Key off.
Disconnect the wire going to the glow plug relay, Circuit 1086 (P/O) point A.
Measure resistance through relay coil, between point A and Point B.
Is the resistance between 1 ohm and 8 ohms?
Yes No GO to S5 . REPLACE glow plug relay.
S5 CHECK SHORT TO POWER
Key off.
Install breakout box. Leave PCM disconnected.
Control circuit still disconnected from the relay.
Key on, engine off.
Measure voltage between test Pin 101 and battery ground.
Is voltage present?
Yes No SERVICE short to power. CLEAR DTC and RETEST. GO to S6 .
S6 CHECK SHORT TO GROUND
Key off.
Breakout box installed. Leave PCM disconnected.
Measure resistance between disconnected wire going to glow plug relay and battery ground.
Is resistance greater than 10,000 ohms?
Yes No GO to S7 . SERVICE short to ground. CLEAR DTC and RETEST.
S7 CHECK CIRCUIT FOR OPEN
Key off.
Breakout box installed. Leave PCM disconnected.
Measure resistance between test Pin 101 and Circuit 1086 (P/O) eyelet going to glow plug relay.
Is resistance less than 5 ohms?
Yes No REPLACE PCM. SERVICE open in Circuit 1086 (P/O).
S8 CHECK GLOW PLUG RELAY
The glow plug ON time is dependent on oil temperature and altitude. The glow plugs come on between 1 to 120 seconds depending on oil temperature and do not come on at all if EOT is above 55°C (131° F). Verify glow plug control ON time by using NGS PID GPCTM.
EOT temperature below 49°C (120°F).
Key on, engine off.
Measure voltage between center terminal of glow plug shunt and battery ground.
Is voltage present for at least 30 seconds?
Yes No GO to S9 . REPLACE glow plug relay.
S9 CHECK GLOW PLUG
Key off.
On the bank with the code, disconnect both connectors on the valve cover gasket.
Inspect both harness connector and gasket for a loose fit. If damaged, repair or replace.
Install Rotunda Glow Plug Injector Adapter 014-00935 or equivalent to the valve cover gasket.
Measure resistance between each of the four glow plug circuits on Rotunda Adapter and engine ground (clean off a spot on the high-pressure oil reservoir to ensure a good ground).
Is resistance less than 2 ohms?
Yes No For DTCs P1391 and P1395, GO to S11 .

For DTCs P1393 and P1396, GO to S12 . GO to S10 .
S10 CHECK UNDER VALVE COVER
Key off.
Remove valve cover and verify that the connections to the glow plugs are OK.
If OK, disconnect the suspect glow plug connector.
Measure resistance between the glow plug and engine ground.
Is resistance less than 2 ohms?
Yes No REPLACE valve cover gasket or UVC harness. REPLACE glow plug. CLEAR DTCs and RETEST.
S11 CHECK GLOW PLUG MONITORING CIRCUIT — DTCS P1391, P1395
Key off.
Disconnect all four valve cover connectors on both right and left banks.
Inspect both harness connector and gasket for a loose fit. If damaged, repair or replace.
Disconnect PCM.
Install breakout box. Leave PCM disconnected.
Measure resistance between all four glow plug circuits on the right bank and test Pin 9 on the breakout box.
Are all readings within 2 ohms of each other?
Yes No GO to S13 . SERVICE open between valve cover connector and PCM connector. VERIFY glow plug shunt nuts are clean and tight.
S12 CHECK GLOW PLUG MONITORING CIRCUIT — DTCs P1393, P1396
Key off.
Disconnect all four valve cover connectors on both right and left banks.
Inspect both harness connector and gasket for a loose fit. If damaged, repair or replace.
Disconnect PCM.
Install breakout box. Leave PCM disconnected.
Measure resistance between all four glow plug circuits on the left bank and test Pin 34 on the breakout box.
Are all readings equal and less than 2 ohms?
Yes No GO to S13 . SERVICE open between valve cover connector and PCM connector. VERIFY glow plug shunt nuts are clean and tight.
S13 CHECK GLOW PLUG MONITORING CENTER CIRCUIT
Key off.
Breakout box installed. Leave PCM disconnected.
Measure resistance between center terminal on glow plug shunt and test Pin 8 on the breakout box.
Is resistance less than 2 ohms?
Yes No GO to S14 . SERVICE open in Circuit 339 (GY).
S14 COMPARE RIGHT BANK TO LEFT BANK
Key off.
Record all readings. The circuits must be within 2 ohms of each other.
Measure resistance between all four glow plug circuits on left bank and test Pins 8, 9 and 34, then all four glow plug circuits on right bank and test Pins 8, 9 and 34.
Are all readings within 2 ohms of each other?
Yes No REPLACE PCM. SERVICE open in the higher resistance circuit. VERIFY glow plug shunt nuts are clean and tight.
S15 DTC P1397 SYSTEM VOLTAGE OUT OF SELF TEST RANGE DURING KOER GLOW PLUG MONITOR SELF TEST
Note: DTC P1397 will set if system voltage is above 14 volts or below 11.8 volts at any time during KOER Glow Plug Self Test. It may be necessary to raise rpm to maintain voltage. If unable to maintain system voltage, service as required according to service manual direction.
Perform KOER Glow Plug Monitor Self Test. With a digital multimeter connected to the battery. Maintain system voltage until test is complete.
Does P1397 still set?
Yes No GO to Pinpoint Test A1 . No concern located at this time.


Other than that the only other thing I can recommend (still learning these 7.3's, did Jeeps and muscle cars for the last 12 years) is snagging an ohm meter and reading out the plugs through the UVCH connector. The link I posted earlier to wood-n-things page with the GPR and GPCM has a great how-to video on there very bottom of the page.

 

Thanks for all of the info. I will have to dig into this this weekend.

If anyone has had a similar experience please share it. Narrowing this issue down looks like a rather commanding job.

Thanks again Krazee!

 

My 99 truck just has the GPR only, it is a e99. But I believe my neighbors 2-99 is the same thing. These are both California trucks bought new by us. Just for information.