Measuring Voltage

Special Tools

EL-39200-B Digital Multimeter (DMM)

For equivalent regional tools, refer to Special Tools.

Danger: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage componentor 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

Caution: Refer to Test Probe Caution.

The following procedure measures the voltage at a selected point in a circuit.

  1. Disconnect the electrical harness connector for the circuit being tested, if necessary.
  2. Enable the circuit and/or system being tested. Use the following methods:
    • Vehicle power mode to Vehicle in Service Mode or Vehicle On.
    • Turn ON the circuit and/or system with a scan tool in Output Controls.
    • Turn ON the switch for the circuit and/or system being tested.
  3. Select the V (AC) or V (DC) position on the digital multimeter (DMM).
  4. Connect the positive lead of the DMM to the point of the circuit to be tested.
  5. Connect the negative lead of the DMM to a good ground.
  6. The DMM displays the voltage measured at that point.