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Discussion Starter · #1 ·
So,
I have a 2003 LB7, bought it and about 2 months later a CEL came on.
P0540
P0380

I fixed the p0380 temporarily by replacing the 175amp fuse in the fusebox.

However, they seem to have come back a few months later. This time however, there was a new code thrown into the mix.
P2229 BARO Sensor Circuit High

I've noticed a similarity in all these codes, they are all Circuit problems.
P0380-Glow Plug/Heater Circuit Problem
P0540-Intake Air Heater Feedback Circuit
P2229- BARO Sensor Circuit High

Naturally, I cleared the codes again, and the P2229 didn't come back, and after replacing the fuse once again, the P0380 was gone. However, the P0540 failed on start up.

I have service records from the previous owner stating that the glow plug relay was replaced, ($110 relay sheesh) So I replaced it again thinking it was bad, and well... It didnt solve anything.

I am here to ask if anyone has had any other sort of codes like this, and knows any common causes before I go into heavy diagnostics... the procedure for diagnosing the P0540 code is quite intensive and could result in a lot of different things. I hear it could possibly be low voltage going through the circuits that could trigger them, so should I test my batteries?

Side note: I've noticed that my interior lights flicker when cranking, only noticed after I replaced all lights with LED's....possibly just noticed because they are brighter.... Is this normal? Or is there something wrong with the batteries not being strong enough.
 

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Discussion Starter · #2 ·
I know what could possibly cause these codes, but as I said. Just trying to get some insight before doing heavy diagnostics...
Cause could be:

Battery
Relays
Fuses
Bad ECM
Bad Glow Plugs
 

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I would trouble shoot the glow plug controller, it has the relays and all the stuff for the glow plugs and the air intake heater.


Kmac
 

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Discussion Starter · #4 ·
I would trouble shoot the glow plug controller, it has the relays and all the stuff for the glow plugs and the air intake heater.


Kmac
Oh, well that's convenient haha, I will try this Monday when I have access to our shops scanner again.
 

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There is a guy on youtube that has a good video about checking glow plugs, controller, and all the wiring. Ill try and find a link.


Kmac
 

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Discussion Starter · #6 ·
Update:

Just threw in an intake air heater relay and a glow plug relay, neither solved the P0380 code, which came back the first start after clearing the codes. What else could be the problem?
 

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Discussion Starter · #7 ·
Also to be noted, I tried turning the glow plug relay on through a scanner (snap on scanner) and almost instantly it came up saying "Glow Plug Timer Time-Out Active" is this normal?

When monitoring glow plug voltage at idle, it was at 14.4v with the Relay off, according to the snap on scanner tips at idle it should read 0.0 to 0.2 Could this be my problem? How can I fix it? (not the relay apparently)

Lastly, I checked the MAF sensor. The Snap on tips say that it should be about 45-50 GM/Sec I noted that mine was around 41-43, and Ive seen a MAF code on the truck before, is this to be worried about?
 

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Discussion Starter · #9 ·
Could be wiring, bad ground or power not getting to the controller or a bad glow plug.


Kmac
I just noticed that I have a loose wire, however, I believe I may have left it off when I accessed the intake air heater relay...I wonder if it is causing the code still. Guess I'll find out tomorrow.
 
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