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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 22 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (2 Of 3)) >> Diagnostic Information and Procedures >> DTC P0685-P0687, P0689, P0690, P1682, P16A7, P16AF, or P16B3 >> Circuit/System Verification

Circuit/System Verification

WARNING: This page is about a different variant/trim than selected.
  1. Ignition - Cycle Off and On & Cycle On and Off

    Verify a click can be heard or felt at the component when the ignition was cycled : KR75 Engine Controls Ignition Relay

    • If a click cannot be heard or felt 

      Refer to : Circuit/System Testing

    • Go to next step : If a click can be heard or felt 
  2. Verify the following parameters are within 3 V of each other :
    • Engine Controls Ignition Relay Feedback Signal
    • Ignition 1 Signal

      or

    • Engine Controls Ignition Relay Feedback 2 Signal
    • Ignition 1 Signal
    • If not within 3 V of each other 

      Refer to : Circuit/System Testing

    • Go to next step : If within 3 V of each other 
  3. Verify the scan tool parameter :
    • Engine Controls Ignition Relay Feedback Signal = The value should not spike or drop out.
    • Engine Controls Ignition Relay Feedback 2 Signal = The value should not spike or drop out.
    • Perform the action while monitoring the parameter :
    • Wiggle the harness and connector : K20 Engine Control Module
    • Wiggle the harness and connector : X50A Fuse Block - Underhood
    • If the value spikes or drops out 

      Repair as necessary - Wiring / Terminal(s) / Electrical Connector(s)

    • Go to next step : If the value does not spike or drop out 
  4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

    Verify the DTC does not set.

    • If the DTC sets 

      Refer to : Circuit/System Testing

    • Go to next step : If the DTC does not set 
  5. All OK.