P0C76
DTC P0C76
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 Present
Typical Scan Tool Data
Circuit/System Description
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 hybrid powertrain control module (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 HCPM 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 not monitored after the motor phase circuits are connected, DTC P1A56 will set. If high voltage is monitored by the HPCM after the motor phase circuits have been connected, 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.
Diagnostic Aids
To clear this DTC from the HPCM, you must use the scan tool Special Functions feature, under the HPCM special functions list.
Special Tools
EL-48900 HEV Safety Kit
Circuit/System Verification
1. Ignition ON, engine OFF, connect a scan tool. Monitor the contactor system status and the hybrid battery terminal voltage parameters in the BECM data list.
2. Ignition OFF, after the relay contactors click open, verify the contactor system status displays open and the hybrid battery terminal Voltage is less than 15 volts.
3. 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.
* Failure to follow the procedures exactly as written may result in serious injury or death.
Ignition OFF, in order to diagnose a stuck high voltage contactor relay, disable the high voltage at the drive motor generator battery. Refer to High Voltage Disabling.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair. Verification Tests
To clear this DTC from the HPCM, you must use the scan tool Special Functions feature, under the HPCM special functions list.