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Home >> Chevrolet >> 2020 >> Express 2500 LS, 6.0L Eng VIN G >> Repair and Diagnosis >> External Pages >> Different car >> Section 94 (Engine Controls And Fuel - 2.8L (LWN) Diesel - Diagnostic Information And Procedures (3 Of 3)) >> Diagnostic Information and Procedures >> DTC P2687-P2689 >> Circuit/System Verification

Circuit/System Verification

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 - On / Vehicle - In Service Mode
  2. Perform the scan tool control function: Fuel Heater Relay - On and Off

    Verify the scan tool parameter:

    • Fuel Heater Relay Control Circuit High Voltage Test Status = Not Run or OK
    • Fuel Heater Relay Control Circuit Low Voltage Test Status = Not Run or OK
    • Fuel Heater Relay Control Circuit Open Test Status = Not Run or OK
    • If not the specified state 

      Refer to: Circuit/System Testing

    • Go to next step: If the specified state 
  3. Perform the scan tool control function: Fuel Heater Relay - On and Off

    Verify a click can be heard or felt at the component when the scan tool control function was commanded: KR22 Fuel Heater 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 
  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 is not set 
  5. All OK.