DTC P0A81-11: Hybrid/EV Battery Cooling Fan 1 Circuit Short to Ground; DTC P0A814B: Hybrid/EV Battery Cooling Fan 1 Over Temperature [10/2018 - ]: Description

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The battery cooling blower assembly speed is controlled by the hybrid vehicle control ECU. Power is supplied to the battery cooling blower assembly when the MREL terminal of the hybrid vehicle control ECU turns on the IGCT relay. The hybrid vehicle control ECU sends command signals (SI0) to the battery cooling blower assembly to adjust the fan speed to an appropriate speed for the HV battery temperature. The frequency (FP0) of the battery cooling blower assembly is sent to the hybrid vehicle control ECU via the battery voltage sensor as a monitor signal using serial communication.

Fig 1: Battery Cooling Blower Assembly

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DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Warning Indicate
P0A8111	Hybrid/EV Battery Cooling Fan 1 Circuit Short to Ground	Both of the following conditions are met: The speed calculated based on the battery cooling blower assembly output frequency is not within the target control speed range. The battery cooling blower assembly speed is excessively low when a certain level of speed is requested (possibility of an open or short to ground in connected circuits, or motor locking). (2 trip detection logic)	Battery voltage sensor Hybrid vehicle control ECU Battery cooling blower assembly BATT FAN fuse Wire harness or connector	Comes on	Master Warning: Comes on
P0A814B	Hybrid/EV Battery Cooling Fan 1 Over Temperature	Both of the following conditions are met: The HV battery temperature is high and the speed calculated based on the battery cooling blower assembly output frequency is not within the target control speed range. The HV battery temperature is high and the battery cooling blower assembly speed is excessively low when a certain level of speed is requested (possibility of an open or short to ground in connected circuits, or motor locking). (1 trip detection logic)	Battery voltage sensor Hybrid vehicle control ECU Battery cooling blower assembly BATT FAN fuse Wire harness or connector	Comes on	Master Warning: Comes on

RELATED DATA LIST

DTC No.	Data List
P0A8111	Hybrid Battery Cooling Fan 1 Drive Request Hybrid Battery Cooling Fan 1 Drive Status Hybrid Battery Cooling Fan 1 Frequency
P0A814B

The following items can be helpful when performing repairs:

Data List

Hybrid Battery Temperature 1 to 3
BATT Voltage

HINT:

"Hybrid Battery Cooling Fan 1 Frequency" is detected when the battery cooling blower assembly is operating and its value changes in proportion to the battery cooling blower assembly speed.