LEMON Manuals: Even more car manuals for everyone
Home >> Buick >> 2019 >> Regal TourX Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 139 (Engine Controls And Fuel - 3.6L (LGX) - Diagnostic Information And Procedures (P0449-P3436) And Symptoms) >> Diagnostic Information and Procedures >> DTC P0641, P0651, P0697, or P06A3 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2020 Buick Regal and 2019 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle - Off
    2. NOTE:

    Additional DTCs will set when disconnecting the components.

  2. Disconnect the electrical connector at one of the following components, depending on the DTC that is set:

    P0641

    • B1 A/C Refrigerant Pressure Sensor
    • B15 Transmission Internal Mode Switch
    • B23A Camshaft Position Sensor - Bank 1 Exhaust
    • B23B Camshaft Position Sensor - Bank 1 Intake
    • B23C Camshaft Position Sensor - Bank 2 Exhaust
    • B23D Camshaft Position Sensor - Bank 2 Intake
    • B47 Fuel Pressure Sensor
    • B74 Manifold Absolute Pressure Sensor
    • B310 Fuel Pressure/Temperature Sensor

    P0651

    • B19B Brake Booster Vacuum Sensor
    • B22 Brake Pedal Position Sensor
    • B26 Crankshaft Position Sensor
    • B37B Engine Oil Pressure Sensor
    • B75C Multifunction Intake Air Sensor

    P0697

    • B107 Accelerator Pedal Position Sensor 2

    P06A3

    • B107 Accelerator Pedal Position Sensor 1
    • Q38 Throttle Body
  3. Ignition - On / Vehicle - In Service Mode
  4. Verify the scan tool parameter: 5V Reference 1 - 4 Circuit Status = Malfunction - For the circuit that set the DTC.
    • If not the specified state after disconnecting a component from the circuit 

      Test or replace the component: The component that was disconnected last.

    • If the specified state and there are components connected to the circuit 

      Disconnect a component and repeat step 4.

    • Go to next step: If the specified state with all components disconnected from the circuit 
  5. Test for 4. 8 to 5. 2 V between the test points:

    P0641 - 5V Reference 1 Circuit

    • 5 V Reference circuit terminal 2 @ B1 A/C Refrigerant Pressure Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B15 Transmission Internal Mode Switch & Ground
    • 5 V Reference circuit terminal 1 @ B23A Camshaft Position Sensor - Bank 1 Exhaust & Ground
    • 5 V Reference circuit terminal 1 @ B23B Camshaft Position Sensor - Bank 1 Intake & Ground
    • 5 V Reference circuit terminal 1 @ B23C Camshaft Position Sensor - Bank 2 Exhaust & Ground
    • 5 V Reference circuit terminal 1 @ B23D Camshaft Position Sensor - Bank 2 Intake & Ground
    • 5 V Reference circuit terminal 1 @ B47 Fuel Pressure Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B74 Manifold Absolute Pressure Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B310 Fuel Pressure/Temperature Sensor & Ground

    P0651 - 5V Reference 2 Circuit

    • 5 V Reference circuit terminal 3 @ B19B Brake Booster Vacuum Sensor & Ground
    • 5 V Reference circuit terminal 6 @ B22 Brake Pedal Position Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B26 Crankshaft Position Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B37B Engine Oil Pressure Sensor & Ground
    • 5 V Reference circuit terminal 2 @ B75C Multifunction Intake Air Sensor & Ground

    P0697 - 5V Reference 3 Circuit

    • 5 V Reference circuit terminal 1 @ B107 Accelerator Pedal Position Sensor - Sensor 2 & Ground

    P06A3 - 5V Reference 4 Circuit

    • 5 V Reference circuit terminal 6 @ B107 Accelerator Pedal Position Sensor - Sensor 1 & Ground
    • 5 V Reference circuit terminal 5 @ Q38 Throttle Body & Ground
    • If less than 4. 8 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points:

      P0641

      • 5 V Reference circuit terminal X1 40 @ Control module harness & Ground
      • 5 V Reference circuit terminal X1 47 @ Control module harness & Ground
      • 5 V Reference circuit terminal X2 47 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 3 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 5 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 35 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 39 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 40 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 55 @ Control module harness & Ground

      P0651

      • 5 V Reference circuit terminal X1 25 @ Control module harness & Ground
      • 5 V Reference circuit terminal X1 45 @ Control module harness & Ground
      • 5 V Reference circuit terminal X2 27 @ Control module harness & Ground
      • 5 V Reference circuit terminal X2 43 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 6 @ Control module harness & Ground

      P0697

      • 5 V Reference circuit terminal X1 21 @ Control module harness & Ground

      P06A3

      • 5 V Reference circuit terminal X1 23 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 8 @ 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 5. 2 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K20 Engine Control Module
    3. Ignition - On / Vehicle - In Service Mode
    4. Test for less than 1 V between the test points:

      P0641

      • 5 V Reference circuit terminal X1 40 @ Control module harness & Ground
      • 5 V Reference circuit terminal X1 47 @ Control module harness & Ground
      • 5 V Reference circuit terminal X2 47 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 3 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 5 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 35 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 39 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 40 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 55 @ Control module harness & Ground

      P0651

      • 5 V Reference circuit terminal X1 25 @ Control module harness & Ground
      • 5 V Reference circuit terminal X1 45 @ Control module harness & Ground
      • 5 V Reference circuit terminal X2 27 @ Control module harness & Ground
      • 5 V Reference circuit terminal X2 43 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 6 @ Control module harness & Ground

      P0697

      • 5 V Reference circuit terminal X1 21 @ Control module harness & Ground

      P06A3

      • 5 V Reference circuit terminal X1 23 @ Control module harness & Ground
      • 5 V Reference circuit terminal X3 8 @ 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: K20 Engine Control Module
    • Go to next step: If between 4. 8 and 5. 2 V 
  6. All OK.
scientia non olet · About LEMON Manuals