The ABS ECU supplies battery power to the electric motor by way of a motor relay which is controlled by the Electronic Control Unit(ECU). The electric motor pump supplies hydraulic pressure to all wheel brake calipers by operating the piston inside the pump.
The ABS ECU monitors the pump motor relay or fuse open, open or short in motor or motor lock and then sets this code if a malfunction is detected.
Warning lamp is turned OFF unless fault is detected any more when the IG KEY is turned ON again, and wheel speed is more than 12km/h.
Item
Detecting Condition
Possible cause
Case1
DTC Strategy
? Start-up monitoring
? Open or short of power supply circuit
? Faulty HECU
Monitoring Period
? Valve and pump motor test
? Inside the ABS control cycle
Enable Conditions
? The pump motor voltage must be present within a time of 60ms after actuation of the motor relay.
Fail Safe
? Pressure decrease (outlet valve) is no longer possible (wheels block). ABS is switched off immediately.
? The ABS warning lamp is activated and the EBD warning lamp is not activated.
Case2
? Long-term monitoring
? Continuous if no ABS control.
? A high level of pump motor voltage with no actuation of the motor relay for more than 2.5sec.
? The return pump runs continuously. ABS is switched off immediately.
Case3
? Pump slow down monitoring
? After the actuation of the motor relay has elapsed, the pump motor voltage is monitored for a certain time on high level. The time depends on the supply voltage and is in the range of 70ms to 140ms. During that time a low level of pump motor voltage up to 40 ms is tolerated. If the run-on conditions are not met, the pump is activated for 700 ms again. This behavior is repeated for maximum 3 times. If, after the last pump activation, the pump motor run-on is still to short, a failure is detected.
? Pressure decrease (outlet valve) is no longer possible (wheels lock). ABS is switched off immediately.
Case4
? Pump Motor Relay voltage drop monitor
? If the Pump relay is turned on
? The valve relay does not turn on completely. The voltage drop at the semiconductor switch remains more than 2V.
? It may not be possible to run the pump. ABS is switched off.