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.
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.
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<9.4V is continued for 500msec. - If the voltage reachs to more than 9.6V, the controller returns to normal state. | |
Fail Safe | ● Outside the ABS control cycle : inhibit the ABS(TCS) control of front wheels and allow the ABS control of rear wheels, deactivating the motor and the ABS(TCS) warning lamp is directly switched on. When the voltage returns to the normal operating range, enable ABS function and ABS(TCS) warning lamp is switched off and erase the error code of low voltage. ● Inside the ABS control cycle : inhibit the ABS control of front wheels and allow the ABS control of rear wheels, deactivating the motor. The ABS(TCS) warning lamp is directly switched on and the state keeps continuously. the error code is always stored. | ||
Case2(Under voltage) | Enable Conditions | ● When Vign<7.2V is detected while Vign<9.4V is continued for 500msec. - If the voltage reach to more than 7.5V, the controller returns to case1. | |
Fail Safe | ● System down. Both the ABS(TCS) and the EBD function are inhibited. - The valve relay and all solenoids are prevented from being switched on. ● The ABS(TCS) and the EBD warning lamps are activated. | ||
