LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2024 >> Tahoe Commercial, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 7 (Engine Controls And Fuel - 3.0L (Lm2) Diesel - Diagnostic Information And Procedures (1 Of 5)) >> Diagnostic Information and Procedures >> DTC P0186, P0191-P0193, P127C, or P127D >> 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 there are no DTCs set related to the following component/system: Intake Air Temperature Sensor 3
    • Go to next step: If a related DTC is not set 
  3. Verify DTC P0186 is not set.
    • If the DTC is set 

      Refer to: Circuit/System Testing - Test 1

    • Go to next step: If the DTC is not set 
  4. Verify the scan tool parameter: Fuel Rail Pressure Sensor & Fuel Rail Pressure Sensor 2 = 0.4 to 4.7 V
    • If not between 0.4 and 4.7 V 

      Refer to: Circuit/System Testing - Test 2

    • Go to next step: If between 0.4 and 4.7 V 
  5. Engine - Idling
  6. Verify the following parameters are within 25 MPa (3, 626 PSI) of each other:
    • Fuel Rail Pressure Sensor
    • Fuel Rail Pressure Sensor 2
    • If not within 25 MPa (3, 626 PSI) of each other 

      Refer to: Circuit/System Testing - Test 1

    • Go to next step: If within 25 MPa (3, 626 PSI) of each other 
  7. Perform the scan tool control function: Fuel Rail Pressure - From 0 to 50% and back to 0%.

    Verify the scan tool parameter: Fuel Rail Pressure Sensor & Fuel Rail Pressure Sensor 2 = The value should change with each command.

    • If the value does not change 

      Refer to: Circuit/System Testing - Test 2

    • Go to next step: If the value changes 
  8. Ignition - On/Vehicle - In Service Mode
  9. Verify the scan tool parameter: Fuel Rail Pressure Sensor & Fuel Rail Pressure Sensor 2 = The value should not spike or drop out.

    Perform the action while monitoring the parameter:

    • Wiggle the harness and connector(s): B47B Fuel Rail Pressure Sensor
    • Wiggle the harness and connector(s): K20 Engine Control Module
    • If the value spikes or drops out 

      Repair as necessary - Wiring/Terminal(s)/Electrical Connector(s)

    • Go to next step: If the value does not spike or drop out 
  10. 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 
  11. All OK.
scientia non olet · About LEMON Manuals