1996 TOYOTA LAND CRUISER Ect

R14139
ContinuityOpen
Continuity
1
2
5
6
3
A6
A7
R14140
(−) (+)
Continuity
Open
36
51
2
A6 A7
−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
DI−203
1996 LAND CRUISER (RM451U)
3 Check ABS control (solenoid) relay.
CHECK:
Check the continuity between each terminal of the ABS control
(solenoid) relay.
OK:
Terminals A7 −1 and A6− 3Continuity
(Reference value aprox. 80 Ω)
Terminals A7 −5 and A7− 6Continuity
Terminals A7 −2 and A7− 5Open
CHECK:
(a) Apply battery positive voltage between terminals A7 −1
and A6−3.
(b) Check the continuity between each terminal of the ABS control (solenoid) relay.
OK:
Terminals A7 −5 and A7− 6Open
Terminals A7 −2 and A7− 5Continuity
NG Replace ABS control relay.
OK
4 Check for open and short in harness and connector between ABS control (\
sole- noid) relay and ABS ECU (See page IN−28).
NG Repair or replace harness or connector.
OK
If same code is still output after DTC is deleted, check contact condition of each connection.\
If
connections are normal, ECU may be defective.
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−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
DI−207
1996 LAND CRUISER (RM451U)
DTC 21, 22, 23 ABS Actuator Solenoid Circuit
CIRCUIT DESCRIPTION
This solenoid goes on when signals are received from the ECU and controls the pressure acting on the wheel
cylinders thus controlling the braking force.
DTC No.DTC Detecting ConditionTrouble Area
21
Conditions 1 through 3 continue for 0.05 sec. or more:
1. ABS control (solenoid) relay terminal (SR) voltage:
Battery positive voltage
2. Voltage of ABS ECU terminal AST: Battery positive voltage
3. When power transistor of ECU is ON, voltage of terminal SFR is 0 V or battery positive voltage
ABS actuator
 Open or short in SFR circuit
22
Conditions 1 through 3 continue for 0.05 sec. or more:
1. ABS control (solenoid) relay terminal (SR) voltage:
Battery positive voltage
2. Voltage of ABS ECU terminal AST: Battery positive volt- age
3. When power transistor of ECU is ON, voltage of terminal SFL is 0 V or battery positive voltage
ABS actuator
 Open or short in SFL circuit
23
Conditions 1 through 3 continue for 0.05 sec. or more:
1. ABS control (solenoid) relay terminal (SR) voltage:
Battery positive voltage
2. Voltage of ABS ECU terminal AST: Battery positive voltage
3. When power transistor of ECU is ON, voltage of terminal SRR is 0 V or battery positive voltage
ABS actuator
 Open or short in SRR circuit
Fail safe function:
If trouble occurs in the actuator solenoid circuit, the ECU cuts off current to the ABS control (solenoid) relay
and prohibits ABS control.
DI5M2−02
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W02193
2
2 1
3
ABS
Battery
W
B−W
W−BID
1
W−B 1
1
W−B 2
2
3 5
4
6
3
4
DLC1
ABS Actuator ABS Control Relay
Motor
Relay
Solenoid
Relay
ABS ECULG
L−R ABS ECU
ABS ECU
3
4
1
1
13
26
SFR
SFL
SRR
A6
A4 A5
A13
A7A6
A6 A6
A4 A4
A5
A5
A13
A13
F6
EA3
L
B−W
B−W
2
2
2
2
EA31
A7 A7
A7
B−RBL
4
1
B−L
AM1
Monitor
R/B
No. 2
B−W
B−W
R/B
No. 2
F00026
1
3
LOCK
7
4
A5
A4
4
DI−208
−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
1996 LAND CRUISER (RM451U)
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check ABS actuator solenoid.
PREPARATION:
Disconnect the 2 connectors from the ABS actuator.
CHECK:
Check the continuity between terminals A4 − 4 and A5−1, 3, 4
of the ABS actuator connector.
OK:
Continuity
HINT:
Resistance of each solenoid coil is 0.8 − 1.6 Ω
NG Replace ABS actuator.
OK
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−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
DI−209
1996 LAND CRUISER (RM451U)
2 Check for open and short in harness and connector between ABS ECU and ac-
tuator (See page IN−28 ).
NG Repair or replace harness or connector.
OK
If same code is still output after DTC is deleted, check contact condition of each connection.\
If
connector are normal, ECU may be defective.
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BR3583
BR3582F00010
RotorSpeed Sensor
Magnet
To ECU
+V
-V High Speed
Low Speed
Coil
N
S
-
DIAGNOSTICS ANTI-LOCK BRAKE SYSTEM
DI-210
1996 LAND CRUISER (RM451U)
DTC31, 32, 33, 34, 35, 36 Speed Sensor Circuit
CIRCUIT DESCRIPTION
The speed sensor detects wheel speed and sends the ap-
propriate signals to the ECU. These signals are used to control
the ABS system. The front and rear rotors each have 48 serra-
tions.
When the rotors rotate, the magnetic field emitted by the perma-
nent magnet in the speed sensor generates an AC voltage.
Since the frequency of this AC voltage changes in direct propor-
tion to the speed of the rotor, the frequency is used by the ECU
to detect the speed of each wheel.
DTC No.DTC Detecting ConditionTrouble Area
31, 32, 33, 34
Detection of any of conditions (1) through (3):
(1) At vehicle speed of 10 km/h (6 mph) or more, pulses are
not input for 5 sec.
(2) Momentary interruption of the speed sensor signal oc-
curs at least 7 times in the time between switching the igni-
tion switch ON and switching it OFF.
(3) Abnormal fluctuation of speed sensor signals with the
vehicle speed 20 km/h (12 mph) or more.

Right front, left front, right rear and left rear speed sensor

Open or short in each speed sensor circuit

Sensor rotor
35
Speed sensor signal is not input for about 1 sec. while
the left front and right rear speed sensor signals are being
checked with the IG switch ON.

Open in left front or right rear speed sensor circuit
36
Speed sensor signal is not input for about 1 sec. while
the right front and left rear speed sensor signals are being
checked with the IG switch ON.

Open in right front or left rear speed sensor circuit
HINT:

DTC No. 31 is for the right front speed sensor.

DTC No. 32 is for the left front speed sensor.

DTC No. 33 is for the right rear speed sensor.

DTC No. 34 is for the left rear speed sensor.
Fail safe function:
If trouble occurs in the speed sensor circuit, the ECU cuts off current to the ABS control (solenoid) relay and
prohibits ABS control.
DI5M3-02
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W02207W02208W02209
W02210
F00036
Front:
Rear:FL+
FL- FR-
FR+
RL+ RL-
RR+ RR-
-
DIAGNOSTICS ANTI-LOCK BRAKE SYSTEM
DI-212
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check speed sensor.
Front
PREPARATION:
Disconnect speed sensor connector.
CHECK:
Measure resistance between terminals 1 and 2, 3 and 4 of
speed sensor connector.
OK:
Resistance: 0.6 - 2.0 k W
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector and body ground.
OK:
Resistance: 1 M W or higher
Rear
PREPARATION:
Disconnect speed sensor connector.
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector.
OK:
Resistance: 0.5 - 1.6 k W
CHECK:
Measure resistance between terminals 1 and 2 of speed sensor
connector and body ground.
OK:
Resistance: 1 M W or higher
NG Replace speed sensor.
NOTICE:
Check the speed sensor signal last (See page DI-189).
OK
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W04200
Normal Signal WaveformGND
2 ms/Division
1V/Division
DI-213
-
DIAGNOSTICS ANTI-LOCK BRAKE SYSTEM
1996 LAND CRUISER (RM451U)
2 Check for open and short in harness and connector between each speed sensor and ECU (See page IN-27).
NG Repair or replace harness or connector.
OK
3 Check speed sensor and rotor serrations.
Reference: INSPECTION USING OSCILLOSCOPE
PREPARATION:
(a) Remove the ABS ECU with connector still connected.
(b) Connect the oscilloscope to the terminals FR+, FL+, RR+ or RL+ and GND of the ABS ECU.
CHECK:
Drive the vehicle at 30 km/h (19 mph), and check the signal wa-
veform.
OK Turn the IG swithch OFF, check and replace ABS ECU.
NG
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R04759
R04775
BR3795
OKNG
-
DIAGNOSTICS ANTI-LOCK BRAKE SYSTEM
DI-214
1996 LAND CRUISER (RM451U)
4 Check sensor rotor and sensor installation.
Front
PREPARATION:
Remove front axle hub and knuckle spindle (See page
SA-8).
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth.
CHECK:
Check the sensor tip and grease.
OK:
No scratches or foreign objects on the sensor tip and
grease.
Rear
PREPARATION:
Remove the rear brake caliper and disc.
CHECK:
Check the sensor rotor serrations.
OK:
No scratches or missing teeth.
CHECK:
Check the sensor tip.
OK:
No scratches or foreign objects on the sensor tip.
CHECK:
Check the speed sensor installation.
OK:
The installation bolt is tightened properly and there is
no clearance between the sensor and steering
knuckle or rear axle carrier.
NG Replace speed sensor or rotor.
NOTICE:
Check the speed sensor signal last (See page DI-189).
OK
Check and replace ABS ECU.
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