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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 112 (Engine Controls - Self-Diagnostics - 3.0L) >> Diagnostic Tests >> DTC P0506: Idle Speed Low >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: If a fuel trim, HO2S, misfire, system voltage, throttle actuator or TP sensor DTC is also set, diagnose that DTC first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS  .
  1. Warm engine to more than 176°F (80°C). Using scan tool, perform the following procedure using ENGINE SPEED CONTROL special function while monitoring ENGINE SPEED.
    • Command 1600 RPM and hold for 5 seconds.
    • Command 1000 RPM and hold for 5 seconds.
    • Command 600 RPM and hold for 5 seconds.
    If engine speed is consistently 100 RPM less than desired idle speed, go to next step. If engine speed is not consistently less than 100 RPM, problem is intermittent. See DIAGNOSTIC AIDS  .
  2. Check for the following possible causes:
    • System voltage out of range.
    • Carbon around throttle plate/bore.
    • Mechanical engine load.