2079283-2079277-2079309-2079315-2079273

Component Location

General Description

The ABS ECU(Electronic Control Unit) checks the battery voltage to determine, as a safety issue, whether the ABS system can operate normally or not. The normal battery voltage range is essential for controlling the ABS system as instended.

DTC Description

The ABS ECU monitors the battery voltage by reading the value of voltage. When the voltage is lower than the expected normal value, this code is set. The ABS function is prohibited and the EBD function is allowed on LOW VOLTAGE CONDITION, both the ABS and the EBD function are prohibited on UNDER VOLTAGE CONDITION. If the voltage recovers, to within normal operating ranges, then the controller returns to normal operations as well.

DTC Detecting Condition

Item		Detecting Condition	Possible cause
DTC Strategy		● Battery Voltage Monitoring.	● Poor connection in power supply circuit (IGN+) ● Faulty HECU
Detect Mode		● Initial Check ● Outside the ABS control cycle ● Inside the ABS control cycle ● Diagnosis mode ● Failure mode
Case1 (Low voltage)	Enable Conditions	● When Vign<9.5V±0.5V is continued for 500msec during Vref >= 7Km/h. ● When Vign<8.5V±0.5V is continued for 500msec during Vref < 7Km/h or ABS/BTCS control. - If IGN voltage is recovered to normal operating voltage, the system recovers to normal state.
	Fail Safe	● Outside the ABS control cycle : inhibit the ABS/TCS control of front wheels and allow the ABS/TCS control of rear wheels, deactivating the motor and the ABS/TCS warning lamps are directly switched on. When the voltage recovers the normal operating range, enable ABS/TCS functions and warning lamps are switched off and erase the error code. ● Inside the ABS control cycle : inhibit the ABS/TCS control of front wheels and allow the ABS/TCS control of rear wheels, deactivating the motor. The ABS/TCS warning lamps are directly switched on and the state keeps continuously. The error code is always stored.
Case2 (Under voltage)	Enable Conditions	● When Vign<7.2V±0.5V is continued for 56msec. - If IGN voltage is recovered to normal operating voltage, the system recovers to normal state.
	Fail Safe	● System down. The ABS/EBD/TCS functions are inhibited. - The valve relay and all solenoids are prevented from being switched on. ● The ABS/EBD/TCS warning lamps are activated.

Schematic Diagram