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Home >> Chevrolet >> 2024 >> Tahoe Commercial, 4WD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 11 (Engine Controls And Fuel - 3.0L (Lm2) Diesel - Diagnostic Information And Procedures (4 Of 5)) >> Diagnostic Information and Procedures >> DTC P1177 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition/Vehicle - Off
  2. NOTE:

    Additional DTCs will set when disconnecting the components.

  3. Disconnect the electrical connector: B47 Fuel Pressure Sensor
  4. Ignition - On/Vehicle - In Service Mode
  5. Verify the scan tool parameter: Fuel Pump Power Control Module 5V Reference 2 Circuit Status = Malfunction
    • If not the specified state after disconnecting a component from the circuit 

      Test or replace the component: B47 Fuel Pressure Sensor

    • Go to next step: If the specified state with all components disconnected from the circuit 
  6. Test for 4.38 to 4.61 V between the test points: 5 V Reference circuit terminal 1@B47 Fuel Pressure Sensor & Ground
    • If less than 4.38 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module
    3. Test for infinite resistance between the test points: 5 V Reference circuit terminal 12 @Control module harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K20 Engine Control Module
    • If greater than 4.61 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Driver Control Module
    3. Ignition - On/Vehicle - In Service Mode
    4. Test for less than 1 V between the test points: 5 V Reference circuit terminal 12 @Control module harness & Ground
      • If 1 V or greater - Repair the short to voltage on the circuit.
      • If less than 1 V - Replace the component: K111 Fuel Pump Driver Control Module
    • Go to next step: If between 4.38 and 4.61 V 
  7. All OK.