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Home >> Chevrolet >> 2018 >> Suburban 3500 HD LT >> Repair and Diagnosis >> External Pages >> Different car >> Section 9 (Engine Controls And Fuel - 5.3L (L83) Or 6.2L (L86) - DTC P0443 To DTC P3452 And Diagnostic Information And Procedures) >> Diagnostic Information And Procedures >> DTC P0641, P0651, P0697 Or P06A3: 5V Reference Circuit >> Circuit/System Testing

Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2018 GMC Yukon XL, 2018 GMC Yukon, 2018 Chevrolet Tahoe, 2018 Chevrolet Suburban, and 2018 Cadillac Escalade ESV. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Additional DTCs will set when disconnecting the components.
  1. Ignition OFF, disconnect the harness connector at all appropriate sensors for the applicable DTC. Refer to Diagnostic Aids .
  2. Ignition ON.
  3. Test for 4.8 - 5.2 V between one of the 5V reference circuits and ground.
    NOTE: You may have to operate the vehicle within the Conditions for Running the DTC or the conditions that you observed from the Freeze Frame/Failure Records data to duplicate the malfunction.
    • If less than 4.8 V 
    1. Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module.
    2. Test for infinite resistance between the 5V reference circuit for each applicable component and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K20 Engine Control Module.
    • If greater than 5.2 V 
    1. Ignition OFF, disconnect the harness connectors at the K20 Engine Control Module.
    2. Test for less than 1 V between the 5V reference circuit for each applicable component and ground.
      • If 1 V or greater, repair the short to voltage on the circuit.
      • If less than 1 V, replace the K20 Engine Control Module.
    • Go to next step: If between 4.8 - 5.2 V 
  4. Verify the appropriate scan tool 5V Reference 1, 2, 3 or 4 Circuit Status parameter displays OK while connecting each component associated with the 5V reference circuit one at a time.
    NOTE: A short to voltage or ground on the signal circuit of certain components may cause this DTC to set.
    • If OK is not displayed when a component is connected 

      Test the signal circuit of that component for a short to ground or voltage. If the circuit tests normal, replace the component.

    • Go to next step: If OK is displayed after all components have been connected 
  5. All OK.
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