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1987 TBI 350, GMC V1500 service engine soon light

Discussion in 'Performance & Fuel' started by Nodak, Jan 4, 2013.

  1. Nodak

    Nodak New Member

    Hey Nodak here. My 87 suburban V1500 350 auto has been flashing the sevice engine soon light lately. as soon as I shut off the engine and restart, the light goes out. Light comes on, usually after the engine is warmed up, cruising down the highway and tip in the throttle a little more than very slightly. Local "car guy" with code reader gave me a code of 43 ESP. The truck seems to run fine, and if you have to ask about fuel milage, you probably wouldn't know anyway. Any direction or information would be greatly appreciated. Thanks in advance.:grrrrrr:
  2. Toymyster

    Toymyster Rockstar 100 Posts

    Hi Nodak, code 43 seems to be the knock sensor circuit. That would be the part I would check first. It should come on at wide open throttle when engine temp is above 190 deg. Usually, if the Check Engine light comes on during freeway cruise, it would be an EGR valve which should be a code 34.
    Hope this helps.

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