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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 9 (Engine Controls And Fuel - 2.5L (LCV) - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC P0068 or P1101 >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different variant/trim than selected.
  1. Ignition - On / Vehicle - In Service Mode
  2. Verify DTC P0641, P0651, P0697, P06A3, P06D2 is not set.
    • Go to next step: If none of the DTCs are set 
  3. Verify the scan tool parameter: Throttle Body Idle Air Flow Compensation = Less than 90%
    • Go to next step: If less than 90% 
  4. Perform the scan tool control function: Throttle Sweep - Start

    Verify the scan tool parameter: Throttle Position Sensors 1 and 2 = Agree

    • Go to next step: If the specified state 
  5. Verify the scan tool parameter: MAP Sensor = The value should be within the range listed in the table: Altitude Versus Barometric Pressure
    • If not in the specified range 
  6. Refer to: DTC P0106, P0107, or P0108 
    • Go to next step: If in the specified range 
  7. Verify the following conditions do not exist:
    • B74 Manifold Absolute Pressure Sensor - Leaking @ O-Ring - Missing / Visible Damage
    • B75C Multifunction Intake Air Sensor - Contamination of the measuring element /Cracked/Loose Clamps / Visible Damage/Water intrusion
    • Q38 Throttle Body
      • Coking/Loose Clamps /Visible Damage
      • Restricted - Moisture/Ice
    • Air Cleaner Element - Dirty / Restricted
    • Catalytic Converter - Blocked / Restricted/Visible Damage
    • Engine - Mechanical Condition - Refer to: Symptoms - Engine Mechanical
    • Exhaust System - Leaking /Restricted/ Visible Damage - Refer to: Symptoms - Engine Exhaust
    • Intake Air Duct - Cracked / Loose Clamps / Restricted / Visible Damage
    • Intake Manifold - Cracked / Loose Clamps / Restricted / Vacuum leak/Visible Damage
    • Positive Crankcase Ventilation System
      • Leaking @ O-Ring - Missing / Visible Damage
      • Restricted - Moisture/Ice
      • Incorrect connection /Leaking / Restricted
    • Vacuum Hoses - Kinked / Leaking / Incorrect connection / Restricted
    • Vacuum leak @ Engine - Oil Level Indicator and Tube /Oil Filler Cap
    • If a condition exists 

      Repair or replace the components as necessary.

    • Go to next step: If no condition exists 
  8. Engine - Idling - At normal operating temperature
  9. Verify the scan tool parameter:
    • MAP Sensor = 26 to 52 kPa (3.8 to 7.5 PSI) @ Idle Speed
    • MAP Sensor = The value should change with accelerator pedal input.
    • Go to next step: If between 26 and 52 kPa (3.8 and 7.5 PSI) and changes 
  10. Increase the engine speed slowly to 3k RPM and then back to idle.
  11. Perform the scan tool function: Review Stored Data
  12. Observe the scan tool parameter frame by frame with a scan tool: MAF Sensor

    Verify the parameter changes smoothly and gradually in the recorded data as the engine speed was increased and decreased.

    • If the value does not change smoothly and gradually 

      Refer to: DTC P0101 

    • Go to next step: If the value changes smoothly and gradually 
  13. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

    Verify the DTC does not set.

    • If the DTC sets 

      Repeat the procedure starting at step 1

    • Go to next step: If the DTC is not set 
  14. All OK.