Page 643 of 1399

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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Page 644 of 1399
W02194
Right Front
Speed SensorLeft Front
Speed Sensor
Right Rear
Speed Sensor
Left Rear
Speed Sensor 2
1 2
2 2
1 1 1
GR
W
R
W
B B
B
W W RR
R
G G
G ABS ECU
Bd1
Bf1
Bg1 Bh1
ID3
BQ2
4 9
10
2
7
1
6
2
A13
A12
FR+
FR- FL+ FL-
RR+ RR-RL+
RL-
16
1 2
Bf1 Bd2
Bd1
Bd2
Bg1 Bh1
Bh1
Bh1
Bh1 BQ2
BQ2
BQ2
BQ2 ID3
ID3
ID3
ID3
L
W
WWW
B FSS
RSS
B
1 1
2
1
2 2
4 1
16
4
4
LLL
BR
BR-B
W-B
3
3 33
Y P
V
Y-G
A13
A13
A13
A13
A12
A12
A12
A12
5
5 11
5 22
9
8
DI-211
-
DIAGNOSTICS ANTI-LOCK BRAKE SYSTEM
1996 LAND CRUISER (RM451U)
WIRING DIAGRAM
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Page 645 of 1399
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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Page 647 of 1399

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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W02195
ECU−IG
Ignition Switch
GNDABS ECU
B−W
J6
Junction
Connector
W
B−L
6
EA2
AM1
IE
3 4
Deceleration
Sensor
2
2
2
2 2
2
2
A13
A13 A13
Battery
AM1
GND
B−W
B−Y
B
B
BB
B
BR BR
BR
F6 1
1
13
+B
12
15
4 R/B No. 2
R/B No. 2
−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
DI−215
1996 LAND CRUISER (RM451U)
DTC 41 IG Power Source Circuit
CIRCUIT DESCRIPTION
This is the power source for the ECU, hence the CPU and actuators.
DTC No.DTC Detecting ConditionTrouble Area
41
Vehicle speed is 3 km/h (1.9 mph) or more and voltage of
ECU terminal IG1 remains at more than 17 V or below 9.5
V for more than 10 sec.Battery
IC regulator
Open or short in power source circuit
Fail safe function:
If trouble occurs in the power source circuit, the ECU cuts off current to the ABS control (solenoid) relay and
prohibits ABS control.
WIRING DIAGRAM
DI5M4−02
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DI−218
−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
1996 LAND CRUISER (RM451U)
DTC 43 Malfunction in Deceleration Sensor
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
43
Either of the following 1 or 2 is detected:
1. After the battery terminal is connected, input from the deceleration sensor does not change at one cycle (0
km/h → more than 30 km/h → 0 km/h) for 16 times con-
tinuously
2. When the brake pedal is not depressed at vehicle speed of 5 km/h or more, forward and backward G (more than
0.4 G) is detected for 30 seconds or more
Deceleration sensor
Wire harness for deceleration sensor system
INSPECTION PROCEDURE
1 Check deceleration sensor (See page DI−190).
NG Replace deceleration sensor.
OK
2 Check for open or short in harness and connector between sensor and ECU \
(See page IN−28 ).
NG Repair or replace harness and connector.
OK
Check and replace ABS ECU.
DI5M6−02
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W01184
BR−BGR−R
31 6 15
13
Ts
Ts
DLC1 ABS ECU
12 V
E1IH1 A12
EC
GR−R
F00007
Ts
DLC1
E1
−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
DI−235
1996 LAND CRUISER (RM451U)
Ts Terminal Circuit
CIRCUIT DESCRIPTION
The sensor check circuit detects abnormalities in the speed sensor signal which cannot be detecte\
d with
the DTC check. Connecting terminals Ts and E
1 of the DLC1 in the engine compartment starts the check.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check voltage between terminals Ts and E1 of DLC1.
CHECK:
(a) Turn the ignition switch ON.
(b) Measure the voltage between terminals Ts and E
1 of the
DLC1.
OK:
Voltage: 10 − 14 V
OK If ABS warning light does not blink even after Ts and E
1 are connected, ECU may be defective.
NG
DI5MN−02
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