two glow plug codes

[turbotibbo]

i had some issues with a cracked rad and now i have 2 glow plug codes . p0676 , p0673 , first the p0676 one came then a day later the other one came along . the truck was apart for studs but i did not replace the glow plugs or the gpcm , anny insight is welcome thanks .

[kaya@bernhausen]

most likely the gpcm. 6.0 glow plugs rarely fail. and when they do, it'll be one and one only. anytime you have multiple GP codes, it's usually gonna be the gpcm
just test resistance of the 2 glow plugs at their corresponding pins at the gpcm connector. see if they fall within spec.
but first, make sure the gpcm connectors are both seated and latched. very common for the locking tabs on the gpcm to break and the connector back out slightly. if so, you can run a zip tie through connector to hold it to the gpcm. just need to run a washer under each gpcm stud to space it away from the bracket to make enough room for the zip tie. otherwise, you could crack the mounting ears of the gpcm when you bolt it back down

[turbotibbo]

is there a gpcm on the drivers side cover bc i had some coolant spill all in that area thats when i got the first code

[kaya@bernhausen]

no, it's mounted on the pass side cover. what i would do if i were you, is test for voltage at each banks 4 pin GP harness connectors. (#3 on pass side, #6 on dr. side), since those connectors are easy to get to. use a test light. if you have no voltage, immediately after the key has been cycled on, at the pins for 6 and 3 glow plugs, replace the gpcm.