• | 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. |
Circuit | Short to Ground | Open | Short to Voltage |
---|---|---|---|
Operating Conditions: Accessory voltage is 9-18 volts, vehicle power mode is RUN Parameter Normal Range: 0% = OFF, 70% = High | |||
Hybrid Batt Pack Fan Commanded | 0% | 100% | 100% |
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 battery is cooled by a drive motor battery vent fan motor. The battery vent fan motor and battery vent fan relay are located inside the drive motor generator battery assembly. B+ to the battery vent fan is provided from the battery vent fan relay when the BECM supplies a ground to the battery vent fan relay. A grounding wire from the battery vent fan motor assembly completes the path to case ground. A 5-volt circuit is provided from the battery vent fan motor assembly, to the BECM. The BECM uses a pulse width modulated (PWM) signal on the 5 volt circuit to control the battery vent fan motor duty cycle. The battery vent fan motor also supplies an additional 5 volt signal that indicates vent fan speed back to the BECM, the lower the voltage the greater the fan speed. The BECM uses 4 battery temperature sensors, one air inlet duct and one air outlet temperature sensor to control battery vent fan motor operation and speed.
• | The vehicle power mode is RUN. |
• | Accessory voltage is 9-18 volts. |
• | Fan speed commanded 35 percent or higher. |
Fan control signal monitor voltage to BECM is greater than 2.3 volts or less than 0.5 volt for 5 seconds.
DTC P0A81 is a Type B DTC.
DTC P0A81 is a Type B DTC.
Verify the BECM fan fuse is not open.
Hybrid Energy Storage Schematics
Control Module References for scan tool information
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. |
⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the generator battery vent fan relay. |
⇒ | If the voltage is not within the specified range, test the signal circuit for a short to voltage, short to ground, or an open/high resistance. If the circuit tests normal, replace the generator battery vent fan. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for drive motor generator battery control module replacement, setup and programming |