A good friend of mine has been having real problems with his LB7 truck. Been to the shop recently for a few different issues but a hard start keeps coming back. I pulled his codes and came up with this:

P0380 Glow Plug Circ Error Circ A
P0540 Manifold Intake Air Heater Circ
PD000 ???Can't find info???

Any help would be apreciated. We just don't know where to start. The dealer hasn't been much help so far and has been charging for every trip.

Thanks.

Federal or Ca emissions?

For federal emissions, the IAH runs off the glow plug relay assembly so the troubleshooting chart ends up having you repair or replace it.

Ca emissions trucks have a separate relay but they are both powered from the same 175A fuse so to get both codes there could be an open or short to ground in the circuit.

A search for PD000 on the service information site comes up empty. I think it's been discussed here before though.

I'm sure that it is federal emissions. Truck was purchased here in Utah.

I figured that it would be a relay and/or a fuse. I assume that this relay is in the engine compartment fuse box? Truck isn't here so I can't check.

Thanks.

The PD000 is just a general code that states that "there is something wrong" nothing very specific. JCG has the rest taken care of. Let us know what you come up with.

Andy S

The glow plug relay assembly is on the drivers side valve cover against the firewall. It has a couple heavy cables on it that go to the gp buss bars and one to the IAH. It takes a little work to swap it out because it's a little buried, but not too bad. It's #4 in this picture...

Thanks guys...got the relay from the dealer for $55. Will let you know if the solves the problems.

You guys are awesome!

Federal or Ca emissions?

For federal emissions, the IAH runs off the glow plug relay assembly so the troubleshooting chart ends up having you repair or replace it.

Ca emissions trucks have a separate relay but they are both powered from the same 175A fuse so to get both codes there could be an open or short to ground in the circuit.

A search for PD000 on the service information site comes up empty. I think it's been discussed here before though.

I'm getting the same 2 codes. Most of the time they show up together, sometimes 1 will show up and not the other. Does that kinda rule out the fuse issue?
I have searched for the heater itself, but can't find it, where is the darn thing?
When are glow plugs and the intake heater activated? It hasn't been that cold here and the codes have been coming up on days when it is 60-70 deg., but on the flip side there have been mornings in the 50's that codes DON'T get set. Also, no hard starts involved. Any suggestions?
Thanks, Steve