The ABS ECU(Electronic Control Unit) checks the battery voltage and alternator output 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 intended.
The HECU 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/ESP functions are prohibited and the EBD function is allowed on LOW VOLTAGE CONDITION, the ABS/EBD/ESP functions 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 Alternator ● Faulty HECU | ||
Monitoring Period | ● Continuous | |||
Case1 (Low voltage) | Enable Conditions | ● When Vign is lower than 9.3V outside ABS/ESP control. ● When Vign is lower than 9.2V inside ABS/ESP control. - If IGN voltage is recovered to 9.6V, the system recovers to normal state. - The monitored supply voltage is filtered and limited to a rise time of 4 volts per second. | ||
Fail Safe | ● The ABS/ESP functions are inhibited. ● The ABS/ESP warning lamps are activated. | |||
Case2 (Under voltage) | Enable Conditions | ● When Vign is lower than 7.7V. -The system remains in this condition until IGN voltage is recovered to 7.8V. ● When Vign is lower than 8.2V for more than 20ms - ESP Only. - The system remains in this condition until IGN voltage is recovered to 8.3V for more than 500ms. - The monitored supply voltage is filtered and limited to a rise time of 4 volts per second. Note. Under voltage faults are only entered in the EEPROM if the vehicle speed is > 6km/h. Remark: If FSA test detect under voltage. this will ve entered, because no vehicle speed is available during test. ※ FSA test : fail save circuit test | ||
Fail Safe | ● The ABS/EBD/ESP functions are inhibited. ● The ABS/EBD/ESP warning lamps are activated. | |||
