#2 Glow Plug P0672

vwroad87 · **Posted:** Thu Sep 27, 2018 4:39 pm

Hey, I've tested and replaced the #2 glow plug and tested the harness for the proper pwm signal. All looks good. I can clear the code with my nice snap-on scanner but it keeps re-appearing. Any ideas? And just so I'm not totally insane #2 plug is second from the front of the motor fan side.

EDIT: I have also replaced the GP Relay Module FYI

Sir Sam · **Posted:** Thu Sep 27, 2018 5:34 pm

Did you check resistance of all the other glow plugs from the connector down?

GordnadoCRD · **Posted:** Sat Sep 29, 2018 6:47 pm

A common mistake is the GP leads to be hooked up in reverse. Since the 4 way connector cannot be hooked up in reverse, it would send a #2 code when it's actually connected to #3.

Billybob · **Posted:** Sun Sep 30, 2018 6:56 am

What Gornado said^^^^ Seen many posts like this.

Ludi Neethling · **Joined:** Sat Feb 02, 2013 11:04 am **Posts:** 87

Mine was the wrong way round as well. Luckily I read this before replacing mine.

vwroad87 · **Posted:** Tue Oct 09, 2018 3:59 am

So I tested one other plug I could reach without disassemble and it was fine. Now a few days later the CEL light is off, didn't reset it with the scanner, and I'm just a bit more CRD confused but happy. This thread mentions the mysterious dis-appearing glow plug CEL code as well. Something about some codes will only reset after you cycle/drive the rig a few times?

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=3&t=87788

vwroad87 · **Posted:** Tue Oct 09, 2018 11:21 pm

And the code is back, gremlins :grim:

Billybob · **Posted:** Wed Oct 10, 2018 2:14 am

Deliberately swap over the wiring between plug #2 And plug #3 and see if it then still calls out plug #2...that would indicate a wiring problem of the wiring that normally goes to plug #2.

The 2006 LHD CRD has a known problem with the wiring harness behind the Fuel Filter Head Mounting Bracket getting damaged by the metal bracket. You need to remove this bracket and inspect the harness behind it for any wires being chaffed through to chassis or to other wires in the harness!

The main harness of the CRD KJs goes all around the engine bay like the Beltway around Washington DC. There are some circuits that for instance go from the PDC fuse box under the hood to sensors around the engine...a distance of about 18 inches! However the route taken is about 8 feet actually and hence the issue of the harness behind the mounting bracket. Usually also a few connectors in circuit with this main harness that could have some bad pin contacts...check the Wiring Diagram for the 2006 Jeep KJ to locate these connectors. :wink:

vwroad87 · **Posted:** Wed Oct 10, 2018 3:49 pm

Thanks @Blliybob, I had an issue with the wiring harness to the TCM that took me 6 months off and on by the time I found the dang short. I will look for the issues you described and post my findings.

vwroad87 · **Posted:** Fri Apr 26, 2019 11:05 am

GordnadoCRD wrote:

A common mistake is the GP leads to be hooked up in reverse. Since the 4 way connector cannot be hooked up in reverse, it would send a #2 code when it's actually connected to #3.

Just got around to this again. Yes it was #3 that was bad. Of course I had to remove the CAC hose and flange to get to the plug but at least I don't have an EGR to fight with. These Jeeps are really an addicting game, I can't wait to get the "high score" of having a good running rig and no CEL. All better again.

Thanks GordnadoCRD et al for all the help you give us newbies, still feel new around here even after a couple of years.

vwroad87 · **Posted:** Wed May 01, 2019 3:27 pm

Okay not more than 2 days later #4 glow plug went out. Hum, could this be 7 volt ecu driving 5 volt glow plugs? Using new bosch glow plugs, changed them all 15K miles ago?

GordnadoCRD · **Posted:** Wed May 01, 2019 9:50 pm

If it is (7v running 5v gps), it would be the first example of such failure I've heard of. Many of us are doing that for better winter starting performance. I have been doing that for the last 2+ years with no failures or problems of any kind.

vwroad87 · **Posted:** Sun May 05, 2019 12:13 pm

Tested resistance at the harness 4 way connector, all good. Cleaned connector with CRC electronic cleaner, reset code. All is well. I though I read somewhere about a gremlin having to reset a phantom glow plug code after monkeying with the system.

#2 Glow Plug P0672

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