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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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W02197
Ignition
Switch
Battery
AM1
F61
B−L 2 2
3
4
W
2 12
AM1R/B No. 2
2
BB
EA2
6
B−Y
42
GAUGEY A
A
J1
Junction
Connector
CENTER DIFF. LOCK
Indicator Light Y
C10
P−B
P−B
P−B
C11
5
A1319
EXI
CENTER
DIFF. LOCK
DETECTION
Switch ABS ECU
2
1
3
R/B No. 2
−
DIAGNOSTICS ANTI−LOCK BRAKE SYSTEM
DI−221
1996 LAND CRUISER (RM451U)
DTC 48 Center Differential Lock Circuit
CIRCUIT DESCRIPTION
DTC No.DTC Detecting ConditionTrouble Area
48Open or short circuit in center differential lock circuit
Center differential is lockingCenter differential lock
Center differential lock circuit
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check the center differential is free (Transfer is in H position).
NG Repair the center differential lock system.
OK
DI5M9−02
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Page 729 of 1399

DI5OA−02
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
DI−295
1996 LAND CRUISER (RM451U)
PROBLEM SYMPTOMS TABLE
SymptomSuspect AreaSee page
SET not occourring or CANCEL occurring.
(DTC is Normal)
1. Main Switch Circuit (Cruise control switch)
2. Vehicle Speed Sensor
3. Control Switch Circuit (Cruise control switch)
4. Stop Light Switch Circuit
5. Park/Neutral Position Switch Circuit
6. Actuator Motor Circuit
7. Cruise Control Cable
8. Cruise Control ECUDI−330
DI−306
DI−311
DI−314
DI−322
DI−296
DI−336 IN−28
SET not occurring or CANCEL occurring.
(DTC does not output)1. ECU Power Source Circuit
2. Cruise Control ECUDI−325IN−28
Actual vehicle speed deviates above or below the set speed.
1. Cruise Control Cable
2. Vehicle Speed Signal Abnormal
3. Electronically Controlled Transmission Communication
Circuit
4. Actuator Motor Circuit
5. Idle Signal Circuit (main throttle position sensor)
6. Cruise Control ECUDI−336
DI−310
DI−319
DI−296
DI−316IN−28
Gear shifting frequent between 3rd O/D when driving on uphill
road. (Hurting)1. Electronically Controlled Transmission Communication
Circuit
2. Cruise Control ECUDI−319
IN−28
Cruise control not cancelled, even when brake pedal is de-
pressed.
1. Cruise Control Cable
2. Stop Light Switch Circuit
3. Actuator Motor Circuit
4. Cruise Control ECUDI−336
DI−314
DI−296IN−28
Cruise control not cancelled, even when transmission is shifted to
”N” postion.
1. Cruise Control Cable
2. Park/Neutral Position Switch Circuit
3. Actuator Motor Circuit
4. Cruise Control ECUDI−336
DI−322
DI−296IN−28
Control switch does not operate.
(SET/COAST, A CC/RES, CANCEL not possible)
1. Cruise Control Cable
2. Control Switch Circuit
3. Actuator Motor Circuit
4. Cruise Control ECUDI−336
DI−311
DI−296 IN−28
SET possible at 40 km/h (25 mph) or less, or CANCEL does not
operate at 40 km/h (25 mph) or less.
1. Cruise Control Cable
2. Vehicle Speed Signal Abnormal
3. Actuator Motor Circuit
4. Cruise Control ECUDI−336
DI−310
DI−296IN−28
Poor response is ACCEL and RESUME modes.
1. Cruise Control Cable
2. Electronically Controlled Transmission Communication
Circuit
3. Actuator Motor Circuit
4. Cruise Control ECUDI−336
DI−319
DI−296IN−28
O/D does not RESUME, even though the road is not uphill.
1. Electronically Controlled Transmission Communication
Circuit
2. Cruise Control ECUDI−319
IN−28
DTC memory is erased.1. Back− up Power Source Circuit
2. Cruise Control ECUDI−328 IN−28
DTC is not output, or is output when is should not be.1. Diagnosis Circuit
2. Cruise Control ECUDI−319IN−28
Cruise MAIN indicator light remains ON or fall to light up.1. Cruise MAIN Indicator Light Switch CircuitDI−332
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DI5OB−02
Duty Ratio =A + BA
x 100 (%)
ON
OFF A
B
1 cycle
I00488
Cruise Control ECU
MC
11
C17 MO
L
Cruise Control Actuator
L−RC17
7
6 12
C4
C4
DI−296
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
CIRCUIT INSPECTION
DTC 11 Actuator Motor Circuit
CIRCUIT DESCRIPTION
The actuator motor is operated by signals from the ECU. Acceleration and deceleration signals are trans-
mitted by changes in the Duty Ratio (See note below).
Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For e\
xample, if A is the period of continuity
in one cycle, and B is the period of non −continuity, then.
DTC No.Detection ItemTrouble Area
11Short in actuator motor circuit.
Actuator motor
Harness or connector between cruise control ECU and
actuator motor
Cruise control ECU
WIRING DIAGRAM
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I00414ECTOD/TRIP METER
Cruise Control ECU
4 pulse/
1 rotation
of rotor shaft 4 pulse/
1 rotation
of rotor shaft
Vehicle Speed Sensor
DI−306
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
DTC 21 Open in Vehicle Speed Sensor Circuit
CIRCUIT DESCRIPTION
The vehicle speed sensor circuit is sent to cruise control ECU as vehicle s\
peed signal.
The rotor shaft is driven by the gear of the transmission.
For each rotation of the shaft, the vehicle speed sensor sends a 4 pulse si\
gnal through the combination me-
ter to the cruise control ECU (See the following).
This signal is converted inside the combination meter and sent as a 4 −pulse signal to the cruise control ECU.
The ECU calculates the vehicle speed from this pulse frequency.
DTC No.Detection ItemTrouble Area
21 Speed signal is not input to the cruise control ECU while
cruise control is set.
Combination meter
Harness or connector between cruise control ECU and com-
bination meter, combination meter and vehicle speed sensor
Vehicle speed sensor
Cruise control ECU
DI5OF−02
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I00494
Cruise Control ECUECT
22 9
15
9
E4S2
R−Y
ECM
E7
OD1
ODC17
18
G−R
G−O
C17
R−Y
R−Y
2 EC2 IH2
Ellectronically Con trolled
Transmission Solenoid
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
DI−319
1996 LAND CRUISER (RM451U)
Electronically Controlled Transmission Communication Circuit
CIRCUIT DESCRIPTION
When driving uphill under cruise control, in order to reduce shifting due to ON− OFF overdrive operation and
to provide smooth driving, when down shifting in the electronically controlled transmission occurs, a si\
gnal
to prevent upshift until the end of the up hill slope is sent from the cru\
ise control ECU to the electronically
controlled transmission.
Terminal ECT of the cruise control ECU detects the shift change signal (\
output to electronically controlled
transmission No. 2 solenoid) from the ECM.
If vehicle speed down, also when terminal ECT of the cruise control ECU receives down shifting signal, it
sends a signal from terminal OD to ECM to cut overdrive until the end of the uph\
ill slope, and the gear shifts
are reduced and gear shift points in the electronically controlled transmis\
sion are changed.
WIRING DIAGRAM
DI5OK−02
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AB0119I00012 I00025
ON
OD
(−) (+)
DI−320
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check operation of overdrive.
PREPARATION:
Test drive after engine warms up.
CHECK:
Check that overdrive ON ↔ OFF occurs with operation of OD switch ON−OFF.
NG Check and repair electronically controlledtransmission (See page DI−129 ).
OK
2 Check voltage between terminal OD of harness side connector of cruise co\
ntrol ECU and body ground.
PREPARATION:
(a) Remove the ECU with connector still connected.
(b) Turn ignition switch ON.
(c) Disconnect the ECU connector.
CHECK:
Measure voltage between terminal OD of harness side connec-
tor of ECU and body ground.
OK:
Voltage: 10 − 14 V
NG Go to step 5.
OK
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I00019
ECT
(−) (+)
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
DI−321
1996 LAND CRUISER (RM451U)
3 Check voltage between terminal ECT of cruise control ECU connector and body
ground (On test drive).
PREPARATION:
(a) Connect the ECU connector.
(b) Test drive after engine warms up.
CHECK:
Check voltage between terminal ECT of ECU connector and
body ground when OD switch is ON and OFF.
OK:
OD switch positionVoltage
ON8 − 14 V
OFFBelow 0.5 V
OK Proceed to next circuit inspection shown on
problem symptoms table (See page DI−295 ).
NG
4 Check harness and connector between terminal ECT of cruise control ECU a\
nd electronically controlled transmission solenoid (See page IN−28).
NG Repair or replace harness or connector.
OK
Check and replace cruise control ECU.
5 Check harness and connector between terminal OD of cruise control ECU an\
d terminal OD1 of ECM (See page IN−28 ).
NG Repair or replace harness or connector.
OK
Check and replace cruise control ECU (See
page IN−28 ).
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