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.
Item
|
Detecting
Condition
|
Possible cause
|
DTC
Strategy
|
| •
|
Battery Voltage
Monitoring | |
| •
|
Open or short of power supply circuit
(ABS1) |
|
Case1
(Motor Relay Open
orMotor
Short to GND)
|
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)
|
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 V_MR is not normal even on the
third recheck, the controller recognizes it as
failure. | |
Case3
(Motor
Open, Motor Short
to
BATT)
|
Enable
Conditions
|
| •
|
After 1.8sec from the time that motor
relay is switched OFF, V_MR > 4±0.5V continued for 1.8sec,
the failure is
detected. | |
Case4
(Motor Fuse
Open)
|
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
|
| •
|
ABS/ESC functions are inhibited, EBD
function is allowed and the ABS/ESC warning lamps are
activated. | |
| 1. |
Connect scantool to Data Link
Connector(DLC). |
| 2. |
Ignition "ON" & Engine
"OFF". |
| 3. |
Select the "Actuation Test" mode on the
scantool. |
| 4. |
Inspect operating status of Motor with
Actuation Test.
Specification
: It's normal if operating sound is
heard.
|
|
| 5. |
Does motor operate normally?
|
|
▶ Fault is
intermittent caused by poor connection in power harness (ABS1)
and/or HECU's connector 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.
|
|
| Terminal and Connector
Inspection |
| 1. |
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. |
| 2. |
Thoroughly check connectors for looseness,
poor connection, bending, corrosion, contamination, deterioration,
or damage. |
| 3. |
Has a problem been found?
|
|
▶ Repair as
necessary and then go to "Verification Of Vehicle Repair"
procedure.
|
|
|
▶ Go to
"Power Circuit Inspection"
procedure.
|
|
Open or Short Check
| 1. |
Ignition "ON" & Engine
"OFF". |
| 2. |
Measure voltage between power(ABS1) terminal
of the HECU harness connector and chassis ground.
|
| 3. |
Is the measured value within
specifications?
|
|
▶ Go to
"Ground Circuit Inspection" procedure.
|
|
|
▶ Check for
open or blown 40A (ABS1) fuse referring to "Circuit
Diagram".
▶ Repair open or short in
power circuit between battery and HECU harness connector and
then, go to "Verification Of Vehicle Repair"
procedure.
|
|
| Ground Circuit
Inspection |
Open or Short Check
| 1. |
Ignition "OFF" & Engine
"OFF". |
| 2. |
Disconnect the HECU
connector. |
| 3. |
Measure resistance between ground terminal of
the HECU harness connector and chassis ground.
Specification
: Approx. below 1Ω
| |
| 4. |
Is the measured value 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.
|
|
|
▶ Repair
open or short in ground circuit between HECU harness connector
and chassis ground, and then go to "Verification Of Vehicle
Repair"
procedure.
|
|
| Verification of Vehicle
Repair |
After a repair, it is
essential to verify that the fault has been corrected.
| 1. |
Connect scantool and select "Diagnostic
Trouble Codes(DTCs)" mode. |
| 2. |
Using a scantool, Clear
DTC. |
| 3. |
Operate the vehicle within DTC Detecting
Condition in General Information. (Start and drive vehicle in gear
and maintain vehicle speed at or above 12kmh.
(7.5mph) |
| 4. |
Using a scantool, Check DTC
present. |
| 5. |
Are any DTCs present ?
|
|
▶ Go to the
applicable troubleshooting procedure.
|
|
|
▶ System
performing to specification at this
time.
|
|
