LEMON Manuals: Even more car manuals for everyone
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 >> Fuel Heater Diagnosis >> 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 OFF.
  2. Disconnect the harness connector at the E11B Fuel Heater/Temperature Sensor.
  3. Test for less than 10 Ω between the fuel heater ground circuit terminal 7 and ground.
    • If 10 Ω or greater 

      Repair the open/high resistance in the circuit

    • Go to next step: If less than 10 Ω 
  4. Connect a test lamp between voltage supply circuit terminal 6 and ground.
  5. Ignition On.
  6. Command the Fuel Heater Relay On and Off with a scan tool. The test lamp should turn On and Off when commanded.
    • If the test lamp is always Off 
    1. Verify the fuse is good and there is voltage at the fuse.
      • If fuse is open, replace the fuse and repair the short to ground in the circuit.
      • Go to next step: If fuse is good and no voltage is present
    2. Ignition Off.
    3. Remove the KR22 Fuel Heater Relay from X50B Fuse Block-Underhood Auxiliary.
    4. Verify that a test lamp illuminates between the fuel heater voltage supply circuit terminal B1/87 and ground.
      • If the test lamp does not illuminate, repair the open/high resistance in the circuit.
      • Go to next step: If the test lamp illuminates
    5. Test for less than 2 ohms between the test points: Signal circuit terminal 6 @ Component harness & Terminal C3/30 @ KR22 Fuel Heater Relay
      • If greater than 2 Ω, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the KR22 Fuel Heater Relay.
    • If the test lamp is always On 
    1. Ignition Off.
    2. Remove the KR22 Fuel Heater Relay from X50B Fuse Block-Underhood Auxiliary.
    3. Ignition On.
    4. Test for less then 1 V between the fuel heater voltage supply circuit terminal 6 and ground.
      • If 1 V or greater, repair the short to voltage in the circuit.
      • If less than 1 V, replace the KR22 Fuel Heater Relay.
    • Go to next step: If the test lamp turns On and Off 
  7. Replace the E11B Fuel Heater/Temperature Sensor.
scientia non olet · About LEMON Manuals