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A/C and Check Engine Light

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by zcarczar, Jun 13, 2002.

  1. zcarczar

    zcarczar 1/2 ton status

    Feb 10, 2002
    Likes Received:
    Apple Valley California
    My check engine light comes on whenever i turn on my air conditioner, it has a pretty new compressor, and i believe it is throwing codes 42 and 43 which is EST bypass/ failer and ESC failure, i havent been able to get anyone at the shop i work at to look at it yet, it also makes the truck run EXTREMELY bad, it will almost stall when comming from a stop light. The truck is an 89 K5 with a 350 installed within the last year and a half, and a 700-r4
    Thanks in advance
  2. HarryH3

    HarryH3 1 ton status Author

    May 31, 2000
    Likes Received:
    Georgetown, TX
    Is the a/c compressor making a lot of noise when it kicks in? Is sounds like the compressor could be rattling so badly that the knock sensor thinks that it's hearing engine knock all the time. That's one thing that could cause those codes to set.

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