6 Codes Related to Glow Plug Circuit


New member
When I scan my van it gives me 7 codes:
p0675 Cylinder 5 Glow Plug Circuit*
p0672 Cylinder 2 Glow Plug Circuit*
p0671 Cylinder 1 Glow Plug Circuit*
p0380 Glow Plug Circuit Perf
p0674 Cylinder 4 Glow Plug Circuit
p0673 Cylinder 3 Glow Plug Circuit*
p2506 ECM/PCM Power Input Signal Range/Perf_

The guy who I got it from said he replaced the glow plug module along with some other sensors when I purchased it. Drove it home and the next day got a CEL. When I scanned it, this is what I get. Does this mean he didn't clear the codes? Or is it a bad module? I'm assuming that all the GP circuits are going crazy because of the module, or were at some point to cause a trip of a code. How do I check to see if the glow plug module is bad?


First, you should clear the codes and see if they come back.
Next, check the 125 amp main fuse on the front of the battery.
Then, check the connector to the glow plug module to insure it is properly plugged in.
Glow Plug Circuit


New member
I cleared the codes and drove the van for 25 minutes to the hardware store. The CEL was off the whole time. :thumbup: But then when I started it back up to go home, it came back on. :thumbdown: When I got home and read the codes, same set of 7 codes came back.

So today, I checked the 125A fuse on the battery and it looked good. I was able to get battery voltage reading on downstream side of the fuse with a meter.

Next I moved to the Glow Plug Module, and the connectors looked pretty snug and fully connected. I took the glow plug module off and found that it was a newer style than I had read about on the forums. I was expected a silicone sealed assembly with accessable fuseable links. What I found was a two part assembly with an o-ring seal. There were four snaps that allowed me to take it apart:

It looks like the design was changed to further cost reduce the assembly: insert molded connectors, wave soldered pins, o-ring sealing, as well as made it more difficult to "tamper" with to prevent the links from blowing. I came across a few posts with mods to put a fuse block inline with the the GP module so those fuses blow before the GP module, but I'm not sure how to do that on this version of the GP module.

I did what I could to look at the links which were buried inside of the assembly, and they all looked in like new condition (just replaced a few weeks ago).

I've found that I can have the key in position two, erase the codes, and immediately (without turning key to position 0) start the van and drive for extended periods of time without the light coming on. But as soon as I turn the van off and restart, the same codes come back.

One thing of note is I have had issues with my ECU relay. I have it jumpered a la merh4x4's fix with jumping the power from another circuit and have the ecu relay jumped all times. Does this make the GP module shut off at the wrong time or something? Would that cause a trip of the codes?

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