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 functions are prohibited and the EBD function is allowed on LOW VOLTAGE CONDITION, the ABS/EBD 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.
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 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 control of front wheels and allow the ABS control of rear wheels, deactivating the motor and the ABS warning lamps are directly switched on. When the voltage recovers the normal operating range, enable ABS functions and warning lamps are switched off and erase the error code.
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 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 functions are inhibited. - The valve relay and all solenoids are prevented from being switched on.
The ABS/EBD warning lamps are activated.
|
Specification
Normal Voltage Range | ENG "ON" |
9±0.5V ~ 17±0.5V |
Diagnostic Circuit Diagram