4.
Inspect opearating status of motor Actuation Test.
Specification : It's normal if operating sound is heard.
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. The ABS ECU monitors the pump motor continuously. (Self check by actuating the pump motor at 15km/h isn't performed)
Item | Detecting Condition | Possible cause | |
DTC Strategy | ● Voltage Monitoring | ● Open or short of power supply circuit (ABS1) ● Faulty HECU | |
Case 1 | Monitoring Period | ● Once per loop when pump motor is deactivated, but not check during detected high, low voltage or when the controller is switched off. | |
Enable Conditions | ● A failure is detected if pump motor voltage ＞ 0.93V continued for 1.8sec. | ||
Case 2 | Monitoring Period | ● Once per loop when pump motor is activated. | |
Enable Conditions | ● A failure is detected if pump motor voltage ＜ 7.3V continued for 1.8sec. | ||
Case 3 | Monitoring Period | ● Once per loop when pump motor is activated. | |
Enable Conditions | ● A failure is detected if the short circuit event has continuously occurred 3 times. - The short circuit event is counted if pump switch voltage ＞ 0.5V continued for about 1ms when the pump motor is activated. ● In case no electrical pump motor short circuit has been detected, a failure is detected if the mechanically locked pump event has continuously occurred 10 times. - A mechanically locked pump event is counted if pump switch voltage > 0.5V continued for about 20ms when the pump motor is activated. | ||
Case4 | Monitoring Period | ● The active test is initiated by the controller once per IGN cycle in following conditions.
● The test is always done after the end of a pump activation by ABS/TCS/ESP functions. | |
Enable Conditions | ● A defect of the pump is assumed if an insufficient alternator voltage is detected within 14 or 21 ms after the deactivation. The pump motor will then be activated again for about 1.8 s (2nd pump test) and the alternator voltage is evaluated again after deactivation. A failure is detected if this second evaluation also does not show sufficient alternator voltage. | ||
Fail Safe | ● When ABS is inactive Inhibit pump motor activation, deactivate all control functions but EBD. ● During active ABS control Inhibit pump motor activation, deactivate all control functions but EBD on completion of ABS cycle. ● The ABS/TCS/ESP warning lamps are activated. | ||
Connect scantool to Data Link Connector(DLC)
Ignition "ON" ＆ Engine "OFF".
Select the "Actuation Test" mode on the scantool.
Inspect opearating status of motor Actuation Test.
Specification : It's normal if operating sound is heard.
Does a motor 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 "Terminal and Connector Inspection" procedure.
Many malfunctions in the electrical system are caused by poor harness(es) and terminal condition. 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" ＆ Engine "OFF".
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 ABS1 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 connector and 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.
