• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
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 drive motor generator power inverter module assembly (PIM) contains capacitors and a resistor circuit intended to discharge the electrical energy stored within the capacitors. Whenever the high voltage contactor relays are opened, the HPCM connects an internal resistor circuit across the high voltage positive and negative circuits. If high voltage is monitored by the HPCM after the resistor circuit has been connected, the HPCM commands the motor control modules (MCMs) to connect the motor phase circuits across the DC high voltage (HV) positive and negative circuits. If high voltage is monitored by the HPCM after the motor phase circuits have been connected, indicating a stuck-closed contactor, this DTC will set.
• | Ignition OFF, during high voltage shutdown. |
• | Accessory voltage is 9-18 volts. |
High voltage has been detected by the HPCM after the contactors have been commanded to open.
DTC P0C76 is a Type C DTC.
• | DTC P0C76 is a Type C DTC. |
• | To clear this DTC from the HPCM, you must use the scan tool Special Functions feature, under the HPCM special functions list only after the repair is complete. |
Hybrid Energy Storage Schematics
Drive Motor Battery System Description
Control Module References for scan tool information
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
EL-48900 HEV Safety Kit
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. |
Perform the High Voltage Disabling procedure in order to diagnose a stuck high voltage contactor relay.
Perform the Diagnostic Repair Verification after completing the repair.