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CEL code P0356 clarification/understanding

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Old Feb 13, 2014 | 11:33 AM
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chrischaugen's Avatar
chrischaugen
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Question CEL code P0356 clarification/understanding

Can someone please explain to me what I may be missing here. I've been having issues with what I've thought was a miss...bad spark plug/coil pack after changing spark plugs. I started out by testing the cylinders by unplugging the coil packs one at a time to see if there was a change at idle. No change, and no code thrown.

Recently I just replaced the intake manifold gasket. Once I got everything back together, I started the truck and immediately the P0356 code popped up. After doing some research to see what that could be, I noticed that the coil pack plug on #6 had come loose, or had not been connected, therefore setting the CEL.

Can someone please explain to me why that code may have been thrown when the connector was not connected on startup, but it didn't throw the code when I was disconnecting them individually while the engine was running?

Thank so much in advance...I look forward to the explanation.
 
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Old Feb 13, 2014 | 12:41 PM
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Bluegrass 7
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Code 356 is the monitor code for the primary side of that coil circuit back to the PCM driver.
The program detected a misfire at startup before the 356 code.
When you removed the coil plug 'while it was running' the program handled it differently.
In terms of program control it's called ''Executive" program control.
Said another way there is a master control program that directs all the other operations in an order of importance.
Reason is the computer can only do one action at a time with a single processor. With no control, it can't work.
It appears like it does things instantly but it's the processor clock speed that is very fast, making it look that way.
Like some people think they can multitask.
Not true, you can only do one thing at a time.
Switching 'attention quickly' between two actions makes it look so.
Good luck.
 
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Old Feb 13, 2014 | 01:07 PM
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chrischaugen
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Bluegrass, thank you for that explanation. That makes perfect sense, thank you for clearing that up for me.
 
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