The ABS ECU supplies battery power to all solonid valves by way of a valve relay which is controlled by the Electronic Control UNIT(ECU). The valve relay and all solenoid valves are installed inside the HECU ( Hydraulic and Electronic Control Unit ).
ABS ECU monitors voltage of the valve relay to check if ABS ECU can perform ABS control normally. When the valve relay is switched to ON, the HECU will set this code if the solenoid drive voltage is below permissible voltage ranges for a period of time. When the valve relay is switched to OFF, the HECU sets this code if the solenoid drive voltage is over the permissible voltage range for a period of time.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Battery Voltage Monitoring | ● Open or short of power supply circuit (ABS2) ● Faulty HECU |
Case1 (Open) | Detect Mode | ● Initial Check ● Outside the ABS control cycle ● Inside the ABS control cycle ● Diagnosis mode |
Enable Conditions | ● If the valve relay is switched on and the reference voltage of valve relay < 5±0.5V continuously for 56ms, the failure is detected. | |
Case2 (Short or Leakage) | Detect Mode | ● Initial Check ● Failure mode |
Enable Conditions | ● If the valve relay is switched off and Vvr > 6±0.5V or Vvr < 2.5±0.5V continuously for 56ms, the failure is detected. | |
Fail Safe | ● System down. The ABS/EBD/TCS/ESP functions are inhibited. - The valve relay and all solenoids are prevented from being switched on. ● The ABS/EBD/TCS/ESP warning lamps are activated. |
