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Home >> Chevrolet >> 2020 >> Malibu LS >> Repair and Diagnosis >> External Pages >> Different car >> Section 113 (Data Communication System - Diagnostic Information And Procedures (1 Of 2)) >> Diagnostic Information and Procedures >> DTC U0100 - U02FF (with HP4) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
WARNING:

Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed.

The High Voltage Disabling procedure includes the following steps:

  • Identify how to disable high voltage.
  • Identify how to test for the presence of high voltage.
  • Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed.

Before working on any high voltage system, be sure to wear the following Personal Protection Equipment:

  • Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors.
  • Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors.
    • Visually and functionally inspect the gloves before use.
    • Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not.

Failure to follow the procedures may result in serious injury or death.

WARNING:

The eAssist battery pack assembly will utilize an exchange program. Please consult the most recent revision of bulletin/PI# PIC5520, available in Service Information (SI), for a list of approved eAssist battery pack assembly service procedures. Components that may be removed and serviced without exchanging the complete battery pack assembly are identified in the bulletin/PI. Please contact the GM Technical Assistance Center (1-877-446-8227) if you have any questions.

NOTE:

Use the Wiring Schematics and connector end views to identify the device's ground, B+, ignition, accessory wakeup serial data, serial data communication enable, and serial data circuit terminals.

  1. Perform the High Voltage Disabling procedure before proceeding with this diagnostic if the non communicating control module is a high voltage module from the following list. Refer to High Voltage Disabling .
    • K114A Hybrid/EV Powertrain Control Module 1 (or T6 Power Inverter Module)
    • K114B Hybrid/EV Powertrain Control Module 2 (or K16 Battery Energy Control Module)
  2. If high voltage disabling is required, reconnect the 12 V battery after performing the high voltage disabling procedure.
  3. 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 all the harness connectors at the device that is not communicating. It may take up to 10 min for all vehicle systems to power down.
  4. 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.
    • Go to next step: If less than 10 Ω 
  5. Ignition ON/Vehicle In Service Mode.
  6. 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 disconnected device.
    • Go to next step: If the test lamp illuminates 
  7. 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 disconnected device.
    • Go to next step: If the test lamp illuminates 
  8. If equipped, verify a test lamp illuminates between each ignition circuit terminal, which is controlled by a control module, and ground.
    • If the test lamp does not illuminate 
    1. Ignition/Vehicle OFF, remove the test lamp, disconnect the harness connectors at the control module that controls the ignition circuit and all devices that share the same ignition circuit.
    2. Test for infinite resistance between the ignition circuit and ground.
      • If less than infinite resistance, repair the short to ground on the circuit.
      • Go to next step: If infinite resistance
    3. 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.
      • Go to next step: If less than 2 Ω
    4. Reconnect the control module that controls the ignition circuit, ignition ON/Vehicle In Service Mode.
    5. Verify a test lamp illuminates between the ignition circuit terminal and ground.
      • If the test lamp does not illuminate, replace the control module that controls the ignition circuit.
      • Go to next step: If the test lamp illuminates
    6. Ignition/Vehicle OFF, reconnect the first device that shares the same ignition circuit, ignition ON/Vehicle In Service Mode.
    7. Verify a test lamp illuminates between the ignition circuit terminal and ground.
      • If the test lamp does not illuminate, replace the device that was just connected.
      • If the test lamp illuminates and there are more devices to connect, connect the next device and repeat step 8.7 until there are no more devices to connect.
    • Go to next step: If the test lamp illuminates 
  9. 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 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.
    • Go to next step: If the test lamp illuminates 
  10. If equipped, verify a test lamp illuminates between the serial data communication enable 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 less than 2 Ω in the serial data communication enable 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.
    • Go to next step: If the test lamp illuminates 
  11. If equipped, verify a test lamp illuminates between the accessory wakeup serial data 2 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 K114B Hybrid/EV Powertrain Control Module 2.
    2. Test for less than 2 Ω in the accessory wakeup serial data 2 circuit end to end.
      • If 2 Ω or greater, repair the open/high resistance in the circuit.
      • If less than 2 Ω, replace the K114B Hybrid/EV Powertrain Control Module 2.
    • Go to next step: If the test lamp illuminates 
  12. Test for less than 4.5 V between each GMLAN serial data circuit terminal and ground.
    • Go to next step: If less than 4.5 V 
  13. 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.
  14. Test for greater than 100 Ω between each GMLAN serial data circuit terminal and ground.
    • Go to next step: If greater than 100 Ω 
  15. Disconnect the harness connectors at the K56 Serial Data Gateway Module.
  16. Test for less than 2 Ω in each of the GMLAN serial data circuits end to end between the non communicating device and the K56 Serial Data Gateway Module.
    • If 2 Ω or greater 

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

    • Go to next step: If less than 2 Ω 
  17. Reconnect the harness connectors at the K56 Serial Data Gateway Module.
    18. NOTE:

    The following test step is only applicable to a high speed GMLAN device with 2 pairs of serial data circuits or a high speed GMLAN device with an internal terminating resistor.

  18. Test for 110 - 130 Ω between each pair of high speed GMLAN serial data circuits.
    • Go to next step: If between 110 - 130 Ω 
  19. Replace the device that is not communicating.
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