4.
Inspect opearating status of inlet valve with Actuation Test.
Specification : It's normal if operating sound is heard.
The HECU supplies battery power to the electric motor with 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.
Item | Detecting Condition | Possible cause | |
DTC Strategy | ● Battery Voltage Monitoring | ● Open or short of power supply circuit (ABS2) ● Inoperative HECU | |
Case1(Motor Relay Open orMotor Short to GND) | Detect Mode | ● Outside the ABS control cycle ● Inside the ABS control cycle ● Diagnosis mode | |
Enable Conditions | ● If the motor relay is switched ON and motor voltage ＜ (IGN voltage – 4V±0.5V) continued for 49msec, the failure is detected. | ||
Case2 (Motor Lock) | Detect Mode | ● Outside the ABS control cycle ● Diagnosis mode | |
Enable Conditions | ● After motor relay is switched OFF, VMR is measured. If the time which VMR ＞ 1±0.1V is less than evaluation time, recheck is performed again for a maximum of three times. When VMR is not normal even on the third recheck, the controller recognizes it as failure. | ||
Case3(Motor Open, Motor Short to BATT) | Detect Mode | ● Initial Check ● Outside the ABS control cycle ● Diagnosis mode ● Failure mode | |
Enable Conditions | ● After 1.8sec from the time that motor relay is switched OFF, VMR ＞ 4±0.5V continued for 1.8sec, the failure is detected. | ||
Case4(Motor Fuse Open) | Detect Mode | ● Initial Check ● Outside the ABS control cycle ● Inside the ABS control cycle ● Diagnosis mode ● Failure mode | |
Enable Conditions | ● If the motor relay is switched OFF and VMRP (Motor power supply voltage) ＜ 4±0.5V continued for 1sec, the failure is detected. | ||
Fail Safe | ● The ABS/ESP functions are inhibited. ● The ABS/ESP warning lamps are activated and the EBD warning lamp is not activated. ● Motor failure during the ABS control cycle (Case 1, 4) :Inhibit the ABS/ESP control of front wheels, allow the ABS/ESP control of rear wheels, and ABS/ESP warning lamps are switched on at the end of ABS control. | ||
Connect scantool to Data Link Connector(DLC)
Ignition "ON" ＆ Engine "OFF".
Select the "Actuation Test" mode on the scantool.
Inspect opearating status of inlet valve with Actuation Test.
Specification : It's normal if operating sound is heard.
Does a inlet valve operate normally?
▶ Fault is intermittent caused by poor connection in motor circuit or was repaired and HECU memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification Of Vehicle Repair" procedure.
▶ Go to "W/Harness Inspection" procedure.
Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
▶ Repair as necessary and then go to "Verification Of Vehicle Repair" procedure.
▶ Go to "Power Circuit Inspection" procedure.
Ignition "OFF".
Disconnect HECU connector.
Ignition "ON".
Measure voltage between terminal "2" of the HECU harness connector and chassis ground.
Specification : Approx. B+
Is the measured voltage within specifications?
▶ Go to "Ground Circuit Inspection" procedure.
▶ Check for damaged harness and open or short to GND between the battery terminal(+) and terminal "2" of the HECU harness connector. Check for open or blown 40A ABS fuse referring to "Circuit Diagram". Repair as necessary and then go to "Verification Of vehicle Repair" procedure.
Ignition "OFF".
Disconnect HECU connector.
Measure resistance between terminal "1" of the HECU harness connector and chassis ground.
Specification : Approx. below 1 Ω
Is the measured resistance within specifications?
▶ Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification Of Vehicle Repair" procedure.
▶ Check for damaged harness and poor connection between terminal "1" of the HECU harness connectorand chassis ground. Repair as necessary and then go to "Verification Of vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode
Using a scantool, Clear DTC.
Operate the vehicle within DTC Detecting Condition in General Information
Are any DTCs present?
▶ Go to the applicable troubleshooting procedure.
▶ System performing to specification at this time.
