The ABS HECU is composed of a ECU (Electronic Control Unit ) and an HCU( Hydraulic Control Unit), so the HECU hardware includes all solenoid valves inside the unit as well as the ECU.
Solenoid valves are switched to ON, OFF by HECU when the ABS is activated. Solenoid valves function is to increase, decrease or maintain the hydralic pressure supplied to a wheel cylinder.
The HECU monitors the operation of the valves by checking the solenoid circuit voltage and sets this code if an incorrect voltage is detected.
Item
Detecting Condition
Possible cause
DTC Strategy
Internal Monitoring
Faulty HECU
Enable Conditions
If the valve relay is switched ON and corresponding solenoid driver OFF and the voltage of solenoid < 3.5±0.5V continuously for 56ms, the failure is detected.
If the valve relay is switched ON and corresponding solenoid driver ON and the voltage of solenoid > 1.5±0.5V continuously for 56ms, the failure is detected.
Fail Safe
Inhibit the ESP/DBC control and allow the ABS/EBD control.
The ESP/DBC warning lamp is activated.