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Home >> Chevrolet >> 2021 >> Blazer RS, FWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 12 (Engine Controls And Fuel - 2.0L (LSY) - 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 variant/trim than selected.
  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
    • B17 Barometric Pressure Sensor
    • B23E Camshaft Position Sensor - Exhaust
    • B23F Camshaft Position Sensor - Intake
    • B37B Engine Oil Pressure Sensor
    • B47 Fuel Pressure Sensor
    • B65 Intake Manifold Pressure and Air Temperature Sensor
    • B321 Crankcase Pressure Sensor
    • Q42 Turbocharger Wastegate Solenoid Valve
    • M10 Charge Air Cooler Coolant Pump
    • M129A Intake Camshaft Profile Actuator 1
    • M129B Intake Camshaft Profile Actuator 2
    • M129C Intake Camshaft Profile Actuator 3
    • M129D Intake Camshaft Profile Actuator 4
    • M130B Exhaust Camshaft Profile Actuator 2
    • M130C Exhaust Camshaft Profile Actuator 3
    • S126 Drive Mode Select Switch

    P0651

    • B22 Brake Pedal Position Sensor
    • B47B Fuel Rail Pressure Sensor
    • B338A Intake Camshaft Profile Sleeve Position Sensor 1
    • B338B Intake Camshaft Profile Sleeve Position Sensor 2
    • B339A Exhaust Camshaft Profile Sleeve Position Sensor 1
    • B339B Exhaust Camshaft Profile Sleeve Position Sensor 2
    • Q74 Engine Coolant Bypass Valve

    P0697

    • B107 Accelerator Pedal Position Sensor 2

    P06A3

    • Q38 Throttle Body
    • B107 Accelerator Pedal Position Sensor 1
  3. Ignition - On/Vehicle - In Service Mode
  4. Verify the scan tool parameter: 5 V 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 - 5 V Reference 1 Circuit

    • 5 V Reference circuit terminal 1 @ B1 A/C Refrigerant Pressure Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B17 Barometric Pressure Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B23E Camshaft Position Sensor - Exhaust & Ground
    • 5 V Reference circuit terminal 1 @ B23F Camshaft Position Sensor - Intake & Ground
    • 5 V Reference circuit terminal 3 @ B37B Engine Oil Pressure Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B47 Fuel Pressure Sensor & Ground
    • 5 V Reference circuit terminal 2 @ B65 Intake Manifold Pressure and Air Temperature Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B321 Crankcase Pressure Sensor & Ground
    • 5 V Reference circuit terminal 3 @ Q42 Turbocharger Wastegate Solenoid Valve & Ground
    • 5 V Reference circuit terminal 3 @ M10 Charge Air Cooler Coolant Pump & Ground
    • 5 V Reference circuit terminal 4 @ M129A Intake Camshaft Profile Actuator 1 & Ground
    • 5 V Reference circuit terminal 4 @ M129B Intake Camshaft Profile Actuator 2 & Ground
    • 5 V Reference circuit terminal 4 @ M129C Intake Camshaft Profile Actuator 3 & Ground
    • 5 V Reference circuit terminal 4 @ M129D Intake Camshaft Profile Actuator 4 & Ground
    • 5 V Reference circuit terminal 4 @ M130B Exhaust Camshaft Profile Actuator 2 & Ground
    • 5 V Reference circuit terminal 4 @ M130C Exhaust Camshaft Profile Actuator 3 & Ground
    • 5 V Reference circuit terminal 5 @ S126 Drive Mode Select Switch & Ground

    P0651 - 5 V Reference 2 Circuit

    • 5 V Reference circuit terminal 6 @ B22 Brake Pedal Position Sensor & Ground
    • 5 V Reference circuit terminal 3 @ B47B Fuel Rail Pressure Sensor & Ground
    • 5 V Reference circuit terminal 1 @ B338A Intake Camshaft Profile Sleeve Position Sensor 1 & Ground
    • 5 V Reference circuit terminal 1 @ B338B Intake Camshaft Profile Sleeve Position Sensor 2 & Ground
    • 5 V Reference circuit terminal 1 @ B339A Exhaust Camshaft Profile Sleeve Position Sensor 1 & Ground
    • 5 V Reference circuit terminal 1 @ B339B Exhaust Camshaft Profile Sleeve Position Sensor 2 & Ground
    • 5 V Reference circuit terminal 3 @ Q74 Engine Coolant Bypass Valve & Ground

    P0697 - 5 V Reference 3 Circuit

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

    P06A3 - 5 V 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 2 X2 @ Control module harness & Ground
      • 5 V Reference circuit terminal 55 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 59 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 60 X3 @ Control module harness & Ground

      P0651

      • 5 V Reference circuit terminal 36 X2 @ Control module harness & Ground

      P0697

      • 5 V Reference circuit terminal 51 X1 @ Control module harness & Ground

      P06A3

      • 5 V Reference circuit terminal 7 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 49 X1 @ 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 2 X2 @ Control module harness & Ground
      • 5 V Reference circuit terminal 55 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 59 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 60 X3 @ Control module harness & Ground

      P0651

      • 5 V Reference circuit terminal 36 X2 @ Control module harness & Ground

      P0697

      • 5 V Reference circuit terminal 51 X1 @ Control module harness & Ground

      P06A3

      • 5 V Reference circuit terminal 7 X3 @ Control module harness & Ground
      • 5 V Reference circuit terminal 49 X1 @ 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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