Diagnostic Instructions
| • | 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. |
DTC Descriptor
DTC P0C76: Hybrid Battery System High Voltage PresentCircuit/System Description
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.
Conditions for Running the DTC
| • | Ignition OFF, during high voltage shutdown. |
| • | Accessory voltage is 9-18 volts. |
Conditions for Setting the DTC
High voltage has been detected by the HPCM after the contactors have been commanded to open.
Action Taken When the DTC Sets
DTC P0C76 is a Type C DTC.
Conditions for Clearing the 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. |
Reference Information
Schematic Reference
Hybrid Energy Storage Schematics
Connector End View Reference
Description and Operation
Drive Motor Battery System Description
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Special Tools
EL-48900 HEV Safety Kit
Circuit/System Verification
- Clear the DTC information. 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.
- Turn the ignition OFF for 3 minutes.
- Turn the ignition ON.
- Retest for DTC P0C76.
- 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 you observed from the freeze frame/failure records data.
Circuit/System Testing
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.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
