Hi,

I have been getting the P380 code on my truck (California Truck). It is also showing that it is the circuit "A" that has the problem. Does this signify which glow plug may be bad?

Thanks

No

See #3 in my sig.

Thanks...but I do not want have my truck tied up for a day or two. Just want to know what bank and what plug is bad without pulling and testing one by one. I will replace myself in 15 minutes. Each plug is on a separate circuit so which plug is circuit "A"?

Thanks

unplug the 2 connectors at the gpcm hook a test lite to battery and touch each one, a bad one wont lite the light you would need a schematic of them to know which wires go to which plug. or you could figure it out by looking at the wires to each plug. if you want more instruction pm me i could send you the schematics.

PM sent...Thanks Mike!

FWIW ~ CA emission trucks have different GP circuits than the rest ~

Mike...Thanks so much for the guidance. My late father explained the general test to me the same way. I was just looking for updated validation. I found 2 bad glow plugs on the port side; the first 2 plugs closest to the intercooler/radiator. The rest 6 were fine; code eliminated! Total project cost was $31.00 even. The cheapest I found to just isolate the bad plugs was $80.00 plus install and plugs.

Thank you all on this site. This is a great place to learn and share what we all know.