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trouble codes

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by KapeKodK5, Mar 4, 2001.

  1. KapeKodK5

    KapeKodK5 Registered Member

    Mar 3, 2000
    Likes Received:
    I have used my scanner to read the codes and I got 2 codes.
    I got a 33, which is MAF or MAP sensor too high during idle. and code 44, which is lean exhaust condition on O2 sensor. WHat to these codes mean? what do I need to replace or consider replacing. I think i the code 33 would be my Throttle position sensor. The truck is a 1990 350 TBI any help anyone?
  2. Cavalry

    Cavalry 1/2 ton status

    Oct 1, 2000
    Likes Received:
    upstate NY(although I cant figure out why)
    for the 33 code make sure the vac hoses are good and electrical connections are good first. Try this first before replacing the sensor. A 44 you should check the fuel pressure, the o2 sensor wire, the throttle body gasket, vac hoses again, and if all else looks good check the sensor

    84 K5
  3. HarryH3

    HarryH3 1 ton status Author

    May 31, 2000
    Likes Received:
    Georgetown, TX
    Your truck uses a MAP (Manifold Absolute Pressure) sensor. It doesn't have a MAF (Mass Air Flow) sensor, so you can rule that out right away. [​IMG] The next problem is that a bad MAP sensor can also cause the O2 sensor error.

    The MAP measures the vacuum in the intake manifold and is one of the main inputs used by the computer to calculate how much fuel to put into the engine. If it's bad (or the hose going to it is leaking), then the engine will run too rich or too lean (looks like it's too lean in your case).

    Check the MAP sensor first. If you have a service manual, it has instuctions on how to troubleshoot the MAP sensor circuit.

    <font color=black>HarryH3 - '75 K5</font color=black>
    <A target="_blank" HREF=http://ThunderTruck.ColoradoK5.com>http://ThunderTruck.ColoradoK5.com</A>

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