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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 113 (Engine Controls And Fuel - 4.3L (LV1) - Diagnostic Information And Procedures (2 Of 2)) >> 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 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. 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
    • B23 Camshaft Position Sensor
    • B37B Engine Oil Pressure Sensor
    • B47B Fuel Rail Pressure Sensor
    • B75C Multifunction Intake Air Sensor
    • B150 Fuel Tank Pressure Sensor

    P0651

    • B22 Brake Pedal Position Sensor
    • B26 Crankshaft Position Sensor

    P0697

    • B74 Manifold Absolute Pressure Sensor
    • B107 Accelerator Pedal Position Sensor - Sensor 2

    P06A3

    • B107 Accelerator Pedal Position Sensor - 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 @ B23 Camshaft Position Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B37B Engine Oil Pressure Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B47B Fuel Rail Pressure Sensor & Ground
    • 5 V Reference circuit terminal 2 @ B75C Multifunction Intake Air Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B150 Fuel Tank Pressure Sensor & Ground

    P0651 - 5V Reference 2 Circuit

    • 5 V Reference circuit terminal 6 @ B22 Brake Pedal Position Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B26 Crankshaft Position Sensor & Ground

    P0697 - 5V Reference 3 Circuit

    • 5 V Reference circuit terminal 1 @ B74 Manifold Absolute Pressure Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B107 Accelerator Pedal Position Sensor - Sensor 2 & Ground

    P06A3 - 5V Reference 4 Circuit

    • 5 V Reference circuit terminal 2 @ 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 appropriate electrical connector: K20 Engine Control Module
    3. Test for infinite resistance between the test points:

      P0641

      • 5 V Reference circuit terminal 2 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 5 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 10 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 18 X2 @ Control module harness & Ground
      • 5 V Reference circuit terminal 21 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 34 X3 @ Control module harness & Ground

      P0651

      • 5 V Reference circuit terminal 10 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 47 X1 @ Control module harness & Ground

      P0697

      • 5 V Reference circuit terminal 33 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 44 X2 @ Control module harness & Ground

      P06A3

      • 5 V Reference circuit terminal 14 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 34 X2 @ 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 appropriate 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 2 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 5 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 10 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 18 X2 @ Control module harness & Ground
      • 5 V Reference circuit terminal 21 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 34 X3 @ Control module harness & Ground

      P0651

      • 5 V Reference circuit terminal 10 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 47 X1 @ Control module harness & Ground

      P0697

      • 5 V Reference circuit terminal 33 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 44 X2 @ Control module harness & Ground

      P06A3

      • 5 V Reference circuit terminal 14 X1 @ Control module harness & Ground
      • 5 V Reference circuit terminal 34 X2 @ 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.
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