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Home >> Cadillac >> 2021 >> CT5 Sport, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 6 (Engine Controls And Fuel - 3.0L (LGY) - Diagnostic Information And Procedures (2 Of 2)) >> Diagnostic Information and Procedures >> DTC P1176 or P1177 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different variant/trim than selected.
  1. Ignition/Vehicle - Off
  2. Disconnect the appropriate electrical connector:
    • { P1176 } B150 Fuel Tank Pressure Sensor
    • { P1177 } B47 Fuel Pressure Sensor
  3. Ignition - On / Vehicle - In Service Mode
  4. Verify the scan tool parameter: Fuel Pump Power Control Module 5V Reference Circuit Status or Fuel Pump Power Control Module 5V Reference 2 Circuit Status = Malfunction
    • If not the specified state 

      Test or replace the component: The original component that set the DTC

    • Go to next step: If the specified state 
  5. Test for 4.8 to 5.2 V between the test points:
    • { P1176 } 5 V Reference circuit terminal 3 @ Component harness & Ground
    • { P1177 } 5 V Reference circuit terminal 1 @ Component harness & Ground
    • If less than 4.8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Power Control Module
    3. Test for infinite resistance between the test points:
      • { P1176 } 5 V Reference circuit terminal 39 @ Control module harness & Ground
      • { P1177 } 5 V Reference circuit terminal 19 @ Control module harness & Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance - Replace the component: K111 Fuel Pump Power Control Module
    • If greater than 5.2 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K111 Fuel Pump Power Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:
      • { P1176 } 5 V Reference circuit terminal 39 @ Control module harness & Ground
      • { P1177 } 5 V Reference circuit terminal 19 @ 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 Power Control Module
    • Go to next step: If between 4.8 and 5.2 V 
  6. Replace the component: K111 Fuel Pump Power Control Module