Page 849 of 3115

F02859
(-)
(+)
(-)
(+)
BM2
BM1EM1 EM2
- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEMDI-597
790 Author: Date:
2004 LAND CRUISER (RM1071U)
INSPECTION PROCEDURE
1 Check accumulator operation.
PREPARATION:
(a) Turn the ignition switch OFF, and depress the brake pedal 40 times or more.
HINT:
When pressure in the power supply system is released, reaction force becomes light and stroke becomes
longer.
(b) Install the LSPV gauge (SST) to the rear brake caliper and bleed air.
SST 09709-29018
CHECK:
Depress the brake pedal with a force of more than 294 N (30 kgf, 66 lbf) and turn the ignition switch ON, then
check the rear brake caliper pressure when an increase of pressure changes from acutely to mildly.
OK:
5,099 to 8,924 kPa (52 to 91 kgf/cm2, 740 to 1,294 psi) at 20°C (68°F)
HINT:
If the value is not within the standard, cool the engine room and check it again.
NG Replace accumulator.
OK
2 Check operation of hydraulic brake booster pump motor.
PREPARATION:
Disconnect the 2 connectors from the hydraulic brake booster.
CHECK:
Connect the battery positive lead to BM1 or BM2 terminal
and the battery negative lead to EM1 or EM2 terminal of the
hydraulic brake booster (pump motor) connector.
OK:
The operation sound of the pump motor should be
heard.
NG Go to step 7.
OK
Page 850 of 3115

F04506
LOCKON
PH
PHG
F06043
LOCK
PH
PHG
DI-598- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEM
791 Author: Date:
2004 LAND CRUISER (RM1071U)
3 Check pressure switch (PH) operation.
PREPARATION:
(a) Turn the ignition switch OFF, and depress the brake pedal
40 times or more.
HINT:
When pressure in the power supply system is released, reac-
tion force becomes light and stroke becomes longer.
(b) Install the LSPV gauge (SST) to the rear brake caliper
and bleed air.
SST 09709-29018
CHECK:
While checking the voltage between terminals PH and PHG of
the hydraulic brake booster, depress the brake pedal with a
force of more than 294 N (30 kgf, 66 lbf) and turn the ignition
switch ON, then check the rear wheel cylinder pressure when
voltage changes from 6 V to 0 V.
OK:
12,553 to 20,104 kpa (128 to 205 kgf´cm2, 1,820 to
2,916 psi)
PREPARATION:
Turn the ignition switch OFF and disconnect the connector (5P)
from the hydraulic brake booster.
CHECK:
While checking the resistance between terminals PH and PHG,
depress the brake pedal changing the force in a range of 197
N (20 kgf, 44 lbf) to 294 N (30 kgf, 66 lbf) and check the rear
wheel cylinder pressure when resistance changes from 0 kW to
1 kW between PH and PHG.
OK:
11,964 to 18,240 kpa (122 to 186 kgf´cm2, 1,735 to
2,645 psi)
HINT:
After inspection, connect the connector, fill brake reservoir with
brake fluid and clear the DTC (See page DI-505).
OK Go to step 5.
NG
Page 851 of 3115

F06042
LOCKON
PLG
PL
- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEMDI-599
792 Author: Date:
2004 LAND CRUISER (RM1071U)
4 Check for open circuit in harness and connector between pressure switch (PH)
and skid control ECU (See page IN-36).
NG Repair or replace harness or connector.
OK
Replace hydraulic brake booster assembly.
5 Check pressure switch (PL) operation.
PREPARATION:
(a) Turn the motor switch OFF, and depress the brake pedal
40 times or more.
HINT:
When pressure in the power supply system is released, reac-
tion force becomes light and stroke becomes longer.
(b) Install the LSPV gauge (SST) to the rear brake caliper
and bleed air.
SST 09709 -29018
(c) Disconnect the connector (8P) from the hydraulic brake
booster.
CHECK:
While checking the resistance between terminals PL and PLG
of the hydraulic brake booster, depress the brake pedal with a
force of more than 294 N (30 kgf, 66 lbf) and turn the ignition
switch ON, then check the rear wheel cylinder pressure when
the resistance changes from 5.7 kW to 1.0 kW.
OK:
9,022 to 15,102 kpa (92 to 154 kgf´cm2, 1,308 to 2,190
psi)
PREPARATION:
Turn the ignition switch OFF and disconnect the connector (8P)
from the hydraulic brake booster.
CHECK:
While checking the resistance between terminals PL and PLG
of the hydraulic brake booster, depress the brake pedal chang-
ing the force in a range of 197 N (20 kgf, 44 lbf) to 294 N (30 kgf,
66 lbf) and check the rear wheel cylinder pressure when resis-
tance changes from 1.0 kW to 5.7 kW.
OK:
8,532 to 13,337 kpa (87 to 136 kgf´cm2, 1,237 to 1,934
psi)
Page 852 of 3115

DI-600- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEM
793 Author: Date:
2004 LAND CRUISER (RM1071U)
HINT:
After inspection, connect the connector, fill brake reservoir with
brake fluid and clear the DTC (See page DI-505).
NG Replace hydraulic brake booster assembly.
OK
6 Check pressure switch (PH) and pressure switch (PL)
CHECK:
Compare the pressure value of the rear wheel cylinder measured in check pressure switch (PL) operation
with the one measured in check pressure switch (PH) operation.
OK:
Pressure when the voltage between PH and PHG becomes 6 to 0 V > pressure when the resis-
tance between PL and PLG becomes 5.7 kW to 1.0 kW.
Pressure when the resistance between PH and PHG becomes 0 kW to 1 kW > pressure when
the resistance between PL and PLG becomes 1.0 kW to 5.7 kW.
NG Replace hydraulic brake booster assembly.
OK
Check and replace skid control ECU.
7 Check for open or short circuit in harness and connector between hydraulic
brake booster pump motor and hydraulic brake booster (See page IN-36).
NG Replace wire harness.
OK
Page 853 of 3115
- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEMDI-601
794 Author: Date:
2004 LAND CRUISER (RM1071U)
8 Check hydraulic brake booster pump motor (See page BR-64).
NG Replace hydraulic brake booster pump motor.
OK
Replace
hydraulic brake booster.
Page 854 of 3115
F17758
Cowl Side J/B LH BatteryEngine Room J/B
Cowl Side J/B LH
Cowl Side J/B RH J4
J/C
Cowl Side J/B LH
IG1 No. 2 Relay
ECU-IG1
AM1
ALT
MAINFL Block
EE IFIG2
IG1
GND4
GND3
GND1
GND2 A44
A42
A42 A42
A41
A41 2A
2B3
13 J/B No. 2
IFF15 F16
2 12C1
2E 2E
2B
3918 37
12
533B 3E22 4IGN2A
2E41 10 1
1C 1B9 AM2
W-R
B-R B-R
B-R B-G
W-R
L-B
B-R
AA
B-G
W-B B-W
W-B
W-B 4
62
7 IG1
AM1
AM2 IG2
W-B
22
6
17
8
31
6 ABS & BA & TRAC
& VSC ECU
W-B
W-B
W-B
W-B
W-B I18
Ignition SW
DI-602- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEM
795 Author: Date:
2004 LAND CRUISER (RM1071U)
DTC C1257 / 57 Power Supply Drive Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
C1257 / 57When a malfunction inside ECU is detected.
Battery
Power source circuit
Skid control ECU
WIRING DIAGRAM
DIC9Y-01
Page 855 of 3115

F09165
GND1GND2
IG1 GND3
GND4
(-)(+) ON
- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEMDI-603
796 Author: Date:
2004 LAND CRUISER (RM1071U)
INSPECTION PROCEDURE
1 Check battery positive voltage.
OK:
Voltage: 10 to 14 V
NG Check and repair the charging system.
OK
2 Check voltage of the ECU IG power source.
In case of using the hand-held tester:
PREPARATION:
(a) Connect the hand-held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand-held tester main switch ON.
(c) Select the DATA LIST mode on the hand-held tester.
CHECK:
Check the voltage condition output from the ECU displayed on the hand-held tester.
OK:
ºNormalº is displayed.
In case of not using the hand-held tester:
PREPARATION:
Remove the skid control ECU with connectors still connected.
CHECK:
(a) Turn the ignition switch ON.
(b) Measure voltage between terminals IG1 and GND of the
skid control ECU connector.
OK:
Voltage: 10 to 14 V
OK Turn ignition switch OFF, check and replace
skid control ECU.
NG
Page 856 of 3115
F02836
GND1
GND2GND3
GND4
F04448
Driver Side J/B
ECU-IG
DI-604- DIAGNOSTICSABS & VEHICLE STABILITY CONTROL (VSC) &
BRAKE ASSIST (BA) SYSTEM
797 Author: Date:
2004 LAND CRUISER (RM1071U)
3 Check continuity between terminal GND of skid control ECU connector and body
ground.
CHECK:
Measure resistance between terminal GND of the skid control
ECU connector and body ground.
OK:
Resistance: 1 W or less
NG Repair or replace harness or connector.
OK
4 Check ECU-IG fuse.
PREPARATION:
Remove the ECU-IG fuse from the driver side J/B.
CHECK:
Check continuity of the ECU-IG fuse.
OK:
Continuity
NG Check for short circuit in all the harness and
components connected to ECU-IG fuse (See at-
tached wiring diagram).
OK
Check for open circuit in harness and connector between skid control ECU and battery (See page
IN-36).