p0676 issue

[jevc]

SES light was on and it coded a P0676. I replaced all glow plugs and the ucvh was tight and looked good so I did not replace it with a new one. the truck still runs good but the code still reads P0676. could this still be a ucvh issue?

[jevc]

I also got between .2 and .4 ohms on each plug wire connection where it comes thru the valve cover. This is a Californa truck. I cant figure out this gpr vs glow plug modual thing.

[jevc]

o.k. I ohm tested the harness from the gpcm to the valve cover and it all tested ok. as another dignostic test I switched the control harness connectors at the gpmc (green to black, black to green) to see if a different code would come up. the p0676 went away and now read p0683. any ideas?

[klhansen]

If you've verified the wiring outside the valve cover (between GPC and VC gasket) then your problem is at the VC gasket connector or inside at the UVC harness. Did you check the pins on the VC gasket connector when you did the GP's? Might be a pin that's corroded or burnt.

When you swapped the wires and got a code for the opposite head, that says the GPC is working correctly.

GP problems won't affect running, just starting. The GP's are only active for 2 minutes maximum.

[jevc]

The uvch looked good. I did not see any burned pins, cracked wires or loose caps. klhanson< I did follow your information for hard start link and that helped. I got ohm readings of .2-.4 on all glow plugs at the connector on the outside of the valve cover. that is why I thought it may be the gpcm might be the culprit. the p0683 code is not the code for the opposite head. I think it said "open circuit" or something. I appreciate any help or information.
Also, whoever posted the tip for using a piece of tubing to remove the glow plug. thanks. I used a 1 foot piece of gas line from a motorcycle to slip over the tip of the glow plug to remove, insert, and start threading the gp. It would be too easy to loose one down a hole if using a pliers. by the way. 165,000 miles on the truck now.