The drive motor generator battery control module is also referred to as the battery energy control module (BECM). The BECM will diagnose its own systems and determine when a fault condition is present. Diagnostics and system status is communicated from the BECM to the hybrid powertrain control module (HPCM) through the Hybrid LAN communication circuit. The HPCM is the host controller for diagnostic trouble code (DTC) information.

The high voltage (HV) direct current (DC) voltage system is protected by a 125A fuse. The fuse is located in the high voltage manual disconnect lever and can only be serviced by replacing the HV manual disconnect lever. The fuse is positioned between the negative and positive terminals at hybrid battery 11. If the fuse is open or the high voltage manual disconnect lever is removed, the scan tool parameter will display 0 volts for hybrid battery 11. The BECM monitors the high voltage interlock circuit (HVIC) for normal operation along with hybrid battery 11 voltage in order to determine if the high voltage fuse is open. If the fuse is open this could indicate that there may be a short between the positive and negative high voltage DC circuit. The high voltage system is isolated from chassis ground.

DTC P0A95 is a Type C DTC.

Schematic Reference

Hybrid Energy Storage Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

1. Ignition ON, verify 13-19 volts for hybrid battery 11 using a scan tool.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records data.

1. Ignition ON, verify 13-19 volts for hybrid battery 11 using a scan tool.

⇒	If the voltage is not within the specified range, continue with diagnosis and proceed to the next step.

⇒	If the voltage is within the specified range, the condition is not present. Refer to Circuit/System Verification.

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.
2. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
3. With a DMM across the HV terminals on the manual disconnect lever, test the high voltage fuse for less than 1 ohm.

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If the resistance is within the specified range, The fault is internal to the drive motor generator battery. Test the HVIC circuit for a wire to wire short on the HVIC source and return circuits between the X350 and the HV manual disconnect lever connector and repair as needed, if all circuits test normal, replace the drive motor generator battery assembly.

⇒

If the resistance is not within the specified range, visually inspect all high voltage (HV) direct current  (DC) cables for damage or conditions that may have caused them to short together. Inspect the high voltage cables between the drive motor generator battery and the drive motor generator control module, and between the drive motor generator control module and the air conditioning compressor. If any of the HV cables are damaged, replace the damaged HV cables. Continue with diagnosis and proceed to the next step.

4. Install a new HV manual disconnect lever, verify if the HV fuse went open after installing a new HV manual disconnect lever.

⇒	If the HV fuse is not open, continue with diagnosis and proceed to the next step.

⇒	If the fuse did open, the fault is internal to the drive motor generator battery. Replace the drive motor generator battery assembly.

5. Enable the high voltage system. Refer to High Voltage Enabling.
6. Ignition ON, verify 13-19 volts for hybrid battery 11 using a scan tool.

⇒	If the voltage is not within the specified range, continue with diagnosis and proceed to the next step.

⇒	If the voltage is within the specified range, the condition is not present. You may want to operate the A/C system or test drive the vehicle. Refer to Circuit/System Verification.

7. Perform the High Voltage Disabling procedure for servicing at the drive motor generator control module cable connections.
8. Remove the air conditioning control module (ACCM) high voltage cable connector from the drive motor generator power inverter module (PIM).
9. Temporarily install the PIM high voltage distribution cover.
10. Install the drive motor generator control module sight shield.
11. Install a new high voltage manual disconnect lever.
12. Connect the 12 volt battery. Refer to Battery Negative Cable Disconnection and Connection.
13. Place the vehicle in the following condition:

•	Hood Closed

•	Transmission in Park

14. Ignition ON, Wait 3 minutes, using a scan tool verify 13-19 volts for hybrid battery 11.

⇒	If the voltage is with in the specified range, replace the air conditioning compressor. Refer to Air Conditioning Compressor Replacement.

15. Ignition OFF, disable the high voltage at the drive motor generator control module. Refer to High Voltage Disabling.
16. Connect the EL-48458 at the drive motor generator control module. Install a new high voltage manual disconnect lever. Refer to the EL-48458 installation procedure located in High Voltage System Diagnosis.
17. Ignition ON, precharge the HV system by moving the HV contactor relay switch on the tester to the closed position. Verify that the Hi-voltage circuit LED for Hi-voltage greater than 60 volts illuminates and stays illuminated. Wait 3 minutes, verify 13-19 volts for hybrid battery 11, with a scan tool in order to verify if the HV fuse is not open circuit.

⇒	If the voltage is within the specified range, replace the drive motor generator power inverter module and the accessory DC power control module. Refer to Control Module References for replacement, setup, and programming.

18. Ignition OFF remove the EL-48458 . Refer to the removal procedure located in High Voltage System Diagnosis.
19. Disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
20. Disconnect the HV DC cables at the drive motor generator battery.
21. Using a DMM, test for infinite resistance between the HV+ and HV- of the DC cables from the drive motor generator battery to the drive motor generator control module.

⇒	If less than infinite resistance replace the HV DC cable and the high voltage manual disconnect lever.

⇒	If HV cable resistance is infinite resistance, replace the drive motor generator battery assembly.

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.
1. Ignition OFF, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
2. Remove the high voltage manual disconnect lever. Using a DMM, test the high voltage manual disconnect lever for an open/high resistance.

⇒	If NO continuity, or the resistance reading is greater than 1 ohm replace the high voltage manual disconnect lever.

Perform the Diagnostic Repair Verification after completing the repair.