service soon light on

[Blu Beest]

Long time member first time posting, I have a 2002 6.6 L Duramax/Allison, 51K, last week the service soon light came on, I was able to scan it and a P0380 code came up, it comes out as a glow plug heater circuit. Has anyone ran into this problem? smile.gif

[More Power]

This DTC is set when either of two conditions occur.

1- The glow plugs are commanded off and the glow plug feedback is more than 2.0 volts.

2- The glow plugs are commanded on, and the feedback is not between 5.0 volts and 6.2 volts.

Check the heavy red lead at the glow plug relay above the rear of the driver's side valve cover for a loose connection.

There is a 150 amp fuse in the distribution panel above the driver's side wheelwell. Just follow the heavy red lead from the glow plug relay to locate that fuse.

Does the wait to start light cycle normally?

MP

[madmatt]

every p0380 i've seen turned out to be a faulty glowplug controller. it's located @ the rear of the left valve cover. while it's cold out put a test light to the wire that runs from the controller to the glow plugs and cycle your ign. on. your test light should come on/ go off w/ your glow plug indicator lamp in your dash. if not make sure you have power to your controller. It'also helps if you have acess to a scanner so you can make sure your plugs are being commanded on.

[Blu Beest]

Thank you for the info, sorry I didn't reply back sooner, I did some testing today and found out that the glow plug on # 4 was not working, I replaced it and cleared the code, start it up 3 times and fault code did not come back. Thanks againg Carlos F. Amaya :D