DTC P0A81-11: Hybrid/EV Battery Cooling Fan 1 Circuit Short to Ground; DTC P0A81-4B: Hybrid/EV Battery Cooling Fan 1 Over Temperature [12/2022 - ]: Description

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The battery cooling blower assembly speed is controlled by the battery ECU assembly. 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 battery ECU assembly 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 battery ECU assembly as a monitor signal.

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DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Warning Indicate	DTC Output from	Priority	Note
P0A81-11	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 cooling blower assembly Battery ECU assembly BATT FAN fuse Wire harness or connector	Comes on	Master Warning: Comes on	HV Battery	A	SAE Code: P0A84
P0A81-4B	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 cooling blower assembly Battery ECU assembly BATT FAN fuse Wire harness or connector	Comes on	Master Warning: Comes on	HV Battery	A	SAE Code: P0A84

HINT:

"Hybrid/EV 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.