High Voltage System Diagnosis (EL-48458)

High Voltage System Diagnosis (EL-48458)

Tools Required

EL-48458 Pre-Charge Test Tool

Description and Operation

The EL-48458 pre-charge test tool is a device designed to assist in the diagnosis of fault conditions that may be difficult to differentiate between in the drive motor generator battery and the power inverter module (PIM). The internal workings of the pre-charge test tool include high voltage bulk capacitors to simulate the capacitance of the PIM. The high voltage interlock circuit (HVIC) has an added test loop to aid in diagnosis of that function when needed.

In addition, there are electronic components designed to mimic the redundant contactor pulse width modulated (PWM) command circuit in order to facilitate the closing and opening of the drive motor generator battery contactors without a PIM. The box also incorporates a high voltage meter and LED to alert the operator of the presence of high voltage to encourage safe operation.

Installation Procedure

Danger: 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 will perform the following tasks:

* 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.

* Failure to follow the procedures exactly as written may result in serious injury or death.

Ignition OFF, perform the high voltage disable procedure, refer to High Voltage Disabling.

1. Disconnect and remove the ACCM high voltage cables from the high voltage distribution box.
2. Disconnect and Remove the drive motor generator battery high voltage cables from the high voltage distribution box.
3. Connect the drive motor generator battery high voltage cables to the EL-48458. Insure that the safety cover on the EL-48458 is re-installed correctly.
4. Insure that the EL-48458 contactor duty cycle switch is in the Open Position. Insure that the HVIC test loop is installed in the tool.
5. Remove the 56-way connector from the PIM and connect the vehicle harness side connector to the EL-48458.
6. Connect the alligator clip on the EL-48458 to a 12 volt vehicle chassis ground point.
7. Install the high voltage manual disconnect lever.
8. Connect the 12 Volt Battery.
9. Turn the Ignition Key to RUN. The 12 volt power LED on the EL-48458 should illuminate.

^ If the 12 volt power LED does not illuminate, verify the alligator clip connection to ground, then remove the 56-way connector and confirm with a DMM that the 12 volt ignition feed is getting to X1 terminal 9 when the ignition key is in RUN.
^ If power is reaching X1 terminal 9 then the test box has failed and must be replaced.

10. Perform any tests and/or diagnostics as needed.

Removal Procedure

1. Move the EL-48458 contactor duty cycle switch to the Open Position.
2. Observe the High Voltage Decaying on the meter until the greater than 60 Volts LED turns off.
3. Turn the Ignition Key to OFF.
4. Wait 5 minutes.
5. Perform the high voltage disabling procedure. Refer to High Voltage Disabling.
6. Disconnect the 56-Way connector from the pre-charge test box and the alligator clip from the ground connection.
7. Open the high voltage safety cover on the pre-charge test box and measure the high voltage connections inside the test box with a DMM and all appropriate Personal Protection Equipment.
8. When the voltage is deemed safe, disconnect the high voltage cables from the test box and remove the box from the vehicle.
9. Re-assemble the vehicle as instructed in the diagnostic procedure.