EL-50332 Hybrid/EV Battery Service Tool Update

After replacing a hybrid/EV battery section on the 2011-2019 Volt; 2014-2016 ELR, Spark EV; 2017-2018 CT6 PLUG-IN; and 2017-2019 Bolt EV models, the new battery section has to be balanced with the rest of the battery pack.

The battery balance procedure requires using the EL-50332 Hybrid/EV Battery Service Tool. (Fig. 7) When using the tool, it’s critical to connect the cables properly. In addition, the EL-50332 tool occasionally requires software updates.

Fig. 7


Battery Cell Balancing

The EL-50332 Hybrid/EV Battery Service Tool is used to match the voltage level of a replacement battery section to the existing battery sections following a service event. The tool charges or discharges the replacement section, as required, based on measured cell group voltage data.

The EL-50332 tool requires feedback from the Battery Energy Control Module during the balancing process. Communication is through the A4 Hybrid/EV Battery Pack and a low voltage interface harness provided with the EL-50332 tool. The charging and discharging is performed by direct connection to the replacement battery section positive and negative terminals.


Hybrid/EV Battery Cells

Using the Volt as an example, there are 96 cell groups in the hybrid battery assembly. These cell groups are electrically connected in series. The battery cell groups are joined to form three sections.

The Battery Energy Control Module monitors the voltage of the 96 battery cell groups through four Hybrid Battery Interface Control Modules and determines when a fault condition is present. The Hybrid Powertrain Control Module 2 is the host controller for DTC information.


Battery Balance Procedure

TIP: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) must be used.

The EL-50332 tool includes a universal fuse box, a vehicle interface module (Fig. 8) and a number of cables. Before balancing a battery section, make sure all the external EL-50332 components and cables are in good condition and working order.

Fig. 8

Refer to the Hybrid/EV Battery Cell Balancing procedure in the appropriate Service Information for complete instructions on connecting the EL-50332 tool. Here are a few tips to assist on hooking up the tool to a battery section.

  • Connect the EL-50332-120 High Voltage Interface Cable to the EL–50332 Hybrid/EV Battery Service Tool (Fig. 9, #1) and to the EL-50332-105 Universal Fuse Box (not shown).
  • Connect the EL-50332-125 Vehicle Interface Module Low Voltage 24-Pin Cable to the EL-50332-110 Vehicle Interface Module (Fig. 9, #3) and to the EL-50332 Hybrid/EV Battery Service Tool. (Fig. 9, #2). There are two different Vehicle Interface Modules (VIM) to use, depending on the vehicle.

Fig. 9

  • Connect the EL-50332-XX Hybrid/EV Battery Contactor Assembly Interface Cable (use the appropriate cable for the vehicle application and connector type) to the A4 Hybrid/EV Battery Pack (Fig. 10, #3) and to the EL-50332-110 Vehicle Interface Module.

Fig. 10

  • Connect the EL-50332-145 Black/Red/Green Banana Jack Cable to the EL-50332-105 Universal Fuse Box (Fig. 11, #1).
  • Connect the EL-50332-155 Green Banana Jack Cable to the A4 Hybrid/EV Battery Pack ground G340.
  • Connect the EL-50332-145 Black Banana Jack Cable to the appropriate section negative stud to be balanced and the EL-50332-150 Red Banana Jack Cable to the appropriate section positive stud to be balanced.

Fig. 11

If any codes appear when starting up the tool, check the following:

  • Make sure the USB flash drive is fully inserted into the machine.
  • Do not hook the machine to the battery section until instructed to do so by the machine.
  • Update the balance machine software to the latest version available.

The time to complete the balancing process is related to the total capacity of the battery pack and depends on the charge condition of the battery pack and the section being balanced. Larger battery packs will take longer to balance. Also, the more adjustment that is needed, the more time that will be required to complete the balancing.

The EL-50332 tool balances the selected section by charging/discharging, as appropriate. Initial balancing will be in a constant current mode (max 5 amp charge, 7.5 amp discharge). The tool will transition to a constant voltage mode (decreasing current) near the end of the event.

A warranty code and pack voltage current data will be displayed at the conclusion of the balancing event. An audible tone will sound at the end of balancing or if there is a fault condition.


EL-50332 Tool Components

The following cables and components are available with the EL-50332 tool.


Software Updates

Tool software updates for the EL-50332 are available on the GM Dealer Equipment Website (U.S.). GM dealerships can download the updates by going through GM GlobalConnect > Service Workbench > GM Essential Tools – Software Updates.

Follow the on-line instructions. It may take approximately one hour to update the tool software, depending on the download speed of the dealership’s internet connection.

In Canada, go to the Service Department page in GM GlobalConnect. Select “GM Special Tools & Equipment – Software Updates” located under the Applications section.

To update the EL-50332 tool software, use the Update function found under the Utility menu on the tool. Use the USB flash drive that was included with the tool, if available, or locate a suitable USB flash drive.

Install the USB flash drive with the updated software into the USB-A port. When performing an update, the tool will first check the inserted USB drive. Next, the version information of the currently loaded software and the new version information found on the USB drive will be displayed on the screen.

The current software version on the tool also can be checked by going to the Tool Info menu and selecting the Version utility. Tool information available in the Version utility includes the software version, EEPROM, version date, tool serial number, and build number. Use the arrow keys to scroll between the screens of version information.

TIP: To view the EL-50322 Instruction Manual, go to the gmtoolsandequipment.com website and select the Software Downloads link. The manual is listed under Support Documents for the EL-50322 tool. (Fig. 12)

Fig. 12


– Thanks to Chuck Berecz


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  1. What happened to the images ?

  2. Stephen Yale says:

    You should make a video of how to balance the cells on volts and bolts.

  3. Wouldn’t it be smarter to insert this detailed information into SI. It seems redundant to give such details outside the service information techs use for an actual repair.

  4. The article updates information about the tool, including additional cables and components that are now available. Check the GM Dealer Equipment website for the latest software updates.


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