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Thread: no power from PCM to EGR valve

  1. #1
    Registered User
    Join Date
    Jan 2008

    no power from PCM to EGR valve

    99 blazer engine light on for egr issue. checked the wires at the egr plug all are fine except the 12v power supply from the PCM is not there showing 0v. even checked the wire on the pcm c4 black wire 16 and no voltage from ther either. is my pcm fried? really need to get the CEL off so i can get inspected

  2. #2
    Registered User
    Join Date
    Sep 2013
    Have you hit it with a scanner to pull the code? What code is it throwing?

  3. #3
    5.7L VORTEC 350 blazin4low's Avatar
    Join Date
    Aug 2002
    I'm not sure how the egr system is powered through the pcm, but check fuses and relays. I doubt the pcm would just lose the egr function if it was bad.
    Tuned by Bland Tuning
    Transmission built by Transbuilderguy on FSC!
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  4. #4
    I'm BATMAN! Harley's Avatar
    Join Date
    Jun 2003
    Warren, MI
    Are you testing for power on pin 16 while the vehicle is on and calling for EGR? It won't have power unless the EGR valve is supposed to be active.

    Also double check to see if you are getting ground at both the EGR connector and on the black pcm C4 connector pin 20 (white wire), but if you aren't getting any power on pin 16 when the EGR is supposed to be active, the PCM needs to be replaced.
    Black 'n Tanazer, Long Bed, Coupe Quattro, Old Caddy, Old Rice

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