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 drive motor generator battery control module (GBCM) 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 V circuit is provided from the battery vent fan motor assembly, to the GBCM. The GBCM uses a pulse width modulated (PWM) signal on the 5 V circuit to control the battery vent fan motor duty cycle. The battery vent fan motor also supplies an additional 5 V signal that indicates vent fan speed back to the GBCM, the lower the voltage the greater the fan speed. The GBCM 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 fan speed control circuit is greater than 0.9 V for 1 second.

DTC P0BC1 is a type B DTC.

DTC P0BC1 is a type B DTC.

Schematic Reference

Hybrid Cooling Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Drive Motor Generator Battery Cooling Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48900 HEV Safety Kit

Ignition ON, engine OFF, with scan tool, command the battery pack vent fan speed to 60 percent duty cycle. The battery vent fan should turn ON and run at a medium-high speed.

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 drive motor generator battery case upper cover, front cover, and right side cover. Refer to Drive Motor Battery Case Upper Cover, Front Cover, and Right Side Cover Replacement.
3. Disconnect the X2 connector at the GBCM.
4. Ignition OFF, connect the 12 V battery.
5. Ignition ON, test for greater than 0.9 V between the fan speed control circuit terminal 2 and ground.

⇒	If less than the specified value, replace the drive motor generator battery control module.

6. Disconnect the harness connector at the vent fan relay.
7. Ignition OFF, connect a test lamp at the vent fan relay harness connector between terminals 1 and 2. The test lamp should not illuminate.

⇒	If the test lamp illuminates, test the vent fan relay control circuit for a short to ground. If the circuit tests normal, replace the drive motor generator battery control module.

8. Ignition ON, connect a test lamp at the vent fan relay harness connector terminal 4 and ground. The test lamp should not illuminate.

⇒	If the test lamp illuminates, repair the short to B+ on the supply voltage circuit between the battery fan relay and the battery vent motor. If the circuit tests normal, test or replace the relay.

9. Ignition OFF, disconnect the inline harness connector at the drive motor generator battery vent fan.
10. Ignition ON, connect a test lamp at the battery vent fan harness connector terminal 4. The test lamp should not illuminate.

⇒	If the test lamp illuminates, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the drive motor generator battery control module.

11. Test for infinite resistance between terminal 3 and 4 on the drive motor generator battery vent fan relay.

⇒	If less than the specified value, replace the drive motor generator battery vent fan relay.

12. If all circuits test normal, replace the drive motor generator battery vent fan.

Fan Relay Test

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. Ignition OFF, disconnect the drive motor generator battery vent fan relay.
3. Test for 85-110 Ω between terminals 1 and 2.

⇒	If not within the specified range, replace the relay.

4. Test for infinite resistance between the following terminals:

•

1 and 3

•

1 and 4

•

2 and 3

•

3 and 4

⇒	If not the specified value, replace the relay.

5. Install a 5 A fused jumper wire between relay terminal 2 and 12 V. Install a jumper wire between relay terminal 1 and ground. Test for less than 2 Ω between terminals 3 and 4.

⇒	If greater than the specified range, replace the relay.

Perform the Diagnostic Repair Verification after completing the repair.