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Home >> Chevrolet >> 2017 >> Traverse LS Base >> Repair and Diagnosis >> Engine Performance >> System >> Data Communication System >> Diagnostic Information and Procedures >> DTC U18A2: Lost Communication with Fuel Pump Driver Control Module >> Circuit/System Testing
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Circuit/System Testing

NOTE:

Use the schematics and connector end views to identify the device's ground, B+, ignition, accessory wake up serial data, and serial data circuit terminals.

  1. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. Disconnect the harness connectors at the K111 Fuel Pump Driver Control Module. It may take up to 10 min for all vehicle systems to power down.
  2. Test for less than 10 Ω between each ground circuit terminal and ground.
    • If 10 Ω or greater 
    1. Ignition/Vehicle OFF.
    2. Test for less than 2 Ω in the ground circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, repair the open/high resistance in the ground connection.
    • If less than 10 Ω 
  3. Ignition ON/Vehicle In Service Mode.
  4. If equipped, verify a test lamp illuminates between each B+ circuit terminal and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition/Vehicle OFF, remove the test lamp.
    2. Test for less than 2 Ω in the B+ circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition/Vehicle OFF, remove the test lamp.
    2. Test for infinite resistance between the B+ circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K111 Fuel Pump Driver Control Module.
    • If the test lamp illuminates 
  5. If equipped, verify a test lamp illuminates between each ignition circuit terminal and ground.
    • If the test lamp does not illuminate and the circuit fuse is good 
    1. Ignition/Vehicle OFF, remove the test lamp.
    2. Test for less than 2 Ω in the ignition circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse.
    • If the test lamp does not illuminate and the circuit fuse is open 
    1. Ignition/Vehicle OFF, remove the test lamp.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance, replace the K111 Fuel Pump Driver Control Module.
    • If the test lamp illuminates 
  6. If equipped, verify a test lamp illuminates between the accessory wakeup serial data circuit terminal and ground.
    • If the test lamp does not illuminate 
    1. Ignition/Vehicle OFF, remove the test lamp, disconnect the harness connectors at the K9 Body Control Module.
    2. Test for infinite resistance between the accessory wakeup serial data circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the accessory wakeup serial data circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K9 Body Control Module.
    • If the test lamp illuminates 
  7. If equipped, verify a test lamp illuminates between the powertrain sensor bus relay control circuit terminal and ground.
    • If the test lamp does not illuminate 
    1. Ignition/Vehicle OFF, remove the test lamp, disconnect the harness connectors at the K20 Engine Control Module.
    2. Test for infinite resistance between the powertrain sensor bus relay control circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • If infinite resistance
    3. Test for less than 2 Ω in the powertrain sensor bus relay control circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K20 Engine Control Module.
    • If the test lamp illuminates 
  8. Test for less than 4.5 V between each powertrain high speed GMLAN serial data circuit terminal and ground.
    • If 4.5 V or greater 

      Refer to DTC U0074  to test for a short to voltage.

    • If less than 4.5 V 
  9. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
  10. Test for greater than 100 Ω between each powertrain high speed GMLAN serial data circuit terminal and ground.
    • If 100 Ω or less 

      Refer to DTC U0074  to test for a short to ground.

    • If greater than 100 Ω 
  11. Disconnect the harness connectors at the device setting the DTC.
  12. Test for less than 2 Ω in each serial data circuits end to end between the K111 Fuel Pump Driver Control Module and the device setting the DTC.
    • If 2 Ω or greater 

      Repair the open/high resistance in the serial data circuit.

    • If less than 2 Ω 
  13. Replace the K111 Fuel Pump Driver Control Module.
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