Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!

2005 gmc 4.3

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6 years 1 month ago #19990 by Ratrod1
2005 gmc 4.3 was created by Ratrod1
no spark... replaced icm,replaced coil still no spark. tested the icm and 3 other icm's. also not getting a 5v refrence to the icm. stumped. i would like to figure out how to test the pcm.any help would be great thanks

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6 years 1 month ago #20017 by Dylan
Replied by Dylan on topic 2005 gmc 4.3
I'm moving this to the repair section ;)

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6 years 1 month ago #20018 by rockp2
Replied by rockp2 on topic 2005 gmc 4.3
Any codes? Check to see if you are getting a signal from your CKP sensor.

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6 years 1 month ago #20021 by cheryl hartkorn
Replied by cheryl hartkorn on topic 2005 gmc 4.3
what model is this so i can find a wiring diagram??

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6 years 1 month ago #20024 by Matts Auto
Replied by Matts Auto on topic 2005 gmc 4.3
should have 12v on pink wire i believe & ground on black wire to icm

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6 years 1 month ago #20025 by Matts Auto
Replied by Matts Auto on topic 2005 gmc 4.3
i think 12 v on pink wire to icm comes from inj 1 fuse

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6 years 1 month ago #20029 by cheryl hartkorn
Replied by cheryl hartkorn on topic 2005 gmc 4.3
he needs to worry about power and grounds at the pcm first before worrying about power to the icm as he said he doesnt have a 5 volt ref. he might have to start unplugging sensors one at a time if his powers/grounds check out to bring back the 5 volt ref

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6 years 1 month ago #20030 by Tyler
Replied by Tyler on topic 2005 gmc 4.3
I took a shot in the dark and guessed a Sierra 1500. :huh:



Like Matts Auto said, you're looking for B+ on the pink wire and a good ground on the black, KOEO or KOEC. IIRC, the white wire from the PCM will only have 5V on it IF the ICM is working correctly. I believe that 5V is provided by the ICM, which is grounded by the PCM to command spark. 0V on the white wire would be a strike against the ICM, or a possible shorted wire.
Attachments:

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6 years 1 month ago #20045 by cheryl hartkorn
Replied by cheryl hartkorn on topic 2005 gmc 4.3
i must have not understood when the poster said he had no 5 volt ref. i thought he meant he had no 5 volt ref to anything on the truck.

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6 years 1 month ago #20058 by Ratrod1
Replied by Ratrod1 on topic 2005 gmc 4.3
no codes and ckp is recieving 5v

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6 years 1 month ago #20060 by Ratrod1
Replied by Ratrod1 on topic 2005 gmc 4.3
2005 gmc 1500

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6 years 1 month ago #20068 by Tyler
Replied by Tyler on topic 2005 gmc 4.3

Ratrod1 wrote: 2005 gmc 1500


Then the diagram I posted is accurate. Let us know what you find with those voltage tests at the ICM, and we can help further! :cheer:

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