Page 484 of 1399

BE6653
P24460A00950
ON
HT1HT2
(−) (+)
−
DIAGNOSTICS ENGINE
DI−47
1996 LAND CRUISER (RM451U)
DTC P0135 Heated Oxygen Sensor Heater Circuit
Malfunction (Bank 1 Sensor 1)
DTC P0141 Heated Oxygen Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
CIRCUIT DESCRIPTION
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control) on page DI−40.
DTC No.DTC Detecting ConditionTrouble Area
P0135
P0141
When the heater operates, heater current exceeds 2 A
(2 trip detection logic)Open or short in heater circuit of heated oxygen sensor
Heated oxygen sensor heater
ECM
Heater current of 0.25 A or less when the heater operates
(2 trip detection logic)
HINT:
Sensor 1 refers to the sensor closer to the engine body.
Sensor 2 refers to the sensor farther away from the engine body.
WIRING DIAGRAM
Refer to DTC P0125 (Insufficient Coolant Temp. for Closed Loop Fuel Control) on page DI−40 for WIRING
DIAGRAM.
INSPECTION PROCEDURE
1 Check voltage between terminals HT1, HT2 of ECM connector and body ground.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals HT1, HT2 of ECM connec-
tor and body ground.
HINT:
Connect terminal HT1 to bank 1 sensor 1.
Connect terminal HT2 to bank 1 sensor 2.
OK:
Voltage: 9 − 14 V
OK Check and replace ECM (See page IN−28 ).
NG
DI5PC−02
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Page 525 of 1399

A00176
ONSPD
(+)
(−)
BE6653
P24668
AT7809
9 − 14 V
0
Turn the wheel
DI−88
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check operation of speedometer.
CHECK:
Drive the vehicle and check if the operation of the speedmeter in the co\
mbination meter is normal.
HINT:
The vehicle speed sensor is operating normally if the speedometer displa\
y is normal.
NG Check speedometer circuit (See page BE−2 ).
OK
2 Check voltage between terminal SPD of ECM connector and body ground.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page SF−65 ).
(b) Disconnect cruise control ECU connector.
(c) Shift the shift lever to neutral.
(d) Jack up a rear wheels on one side.
(e) Turn ignition switch ON.
CHECK:
Measure voltage between terminal SPD of ECM connector and
body ground when the wheel is turned slowly.
OK:
Voltage is generated intermittently.
NG Check and repair harness and connector between combination meter and ECM.
OK
Check and replace ECM (See page IN−28 ).
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Page 536 of 1399
A00184
STARTIGT
(+)(−)
BE6653
P24674
FI6605
IGT signal waveform
5 m sec/Division (Idling)
IGT
IGF
2 V/Div.
0V 0V
−
DIAGNOSTICS ENGINE
DI−99
1996 LAND CRUISER (RM451U)
4 Check for open and short in harness and connector in IGT signal circuit betwe\
en
ECM and igniter (See page IN−28).
NG Repair or replace harness or connector.
OK
5 Check voltage between terminals IGT of ECM connector and body ground.
PREPARATION:
Remove instrument panel speaker No.1 panel (See page
SF−65 ).
CHECK:
Measure voltage between terminal IGT of ECM connector and
body ground when engine is cranked.
OK:
Voltage: More than 0.1 V and less than 4.5 V
Reference: INSPECTION USING OSCILLOSCOPE
During cranking or idling, check waveforms between terminals
IGT and E1 of engine control module.
HINT:
The correct regulator waveforms are as shown.
NG Check and replace ECM (See page IN−28 ).
NG
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Page 563 of 1399
A00197
ONON
OFF
BE6653
P22965
P22966
G
E
G E Air Filter
Air Filter
DI−126
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
TOYOTA hand −held tester
1 Connect the TOYOTA hand−held tester and check operation of VSV for fuel
pressure control.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the TOYOTA hand−held tester to the DLC3.
(c) Turn ignition switch ON and TOYOTA hand −held tester
main switch ON.
(d) Select the ACTIVE TEST mode on the TOYOTA hand −
held tester.
CHECK:
Check operation of VSV when VSV is operated by the T OYOTA
hand −held tester.
OK:
VSV is ON:
Air from pipe E is flowing out through the air filter.
VSV is OFF:
Air from pipe E is flowing out through pipe G.
OK Check and repair fuel pressure regulator (See page SF−19 ).
NG
2 Check VSV for fuel pressure control (See page SF−59).
NG Replace VSV for fuel pressure control.
OK
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Page 564 of 1399
A00198
ONFPU
(+)
(−)
BE6653
P24688
−
DIAGNOSTICS ENGINE
DI−127
1996 LAND CRUISER (RM451U)
3 Check for open and short in harness and connector between EFI main relay
(Marking: EFI) and ECM (See page IN−28).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN−28 ).
OBD II scan tool (excluding TOYOTA hand −held tester)
1 Check VSV for fuel pressure control (See page SF−59 ).
NG Replace VSV for fuel pressure control.
OK
2 Check voltage between terminal FPU of ECM connector and body ground.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel (See page
SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal FPU of ECM connector and
body ground.
OK:
Voltage: 9 − 14 V
NG Check for open and short in harness and con- nector between EFI main relay (Marking: EFI)
and ECM (See page IN−28 ).
OK
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Page 568 of 1399

DI5K9−03
Q08225
Q08634
TOYOTA Hand−held Tester
DLC3
−
DIAGNOSTICS AUTOMATIC TRANSMISSION
DI−131
1996 LAND CRUISER (RM451U)
PRE−CHECK
1. DIAGNOSIS SYSTEM
(a) Description
When troubleshooting OBD II vehicles, the only dif-
ference from the usual troubleshooting procedure
is that you connect to the vehicle the OBD II scan
tool complying with SAE J1978 or TOYOTA hand −
held tester, and read off various data output from
the vehicle’s ECM.
OBD II regulations require that the vehicle’s on −
board computer lights up the Malfunction Indicator
Lamp (MIL) on the instrument panel when the com-
puter detects a malfunction in the computer itself or
in drive system components which affect vehicle
emissions. In addition to the MIL lighting up when
a malfunction is detected, the applicable DTCs pre-
scribed by SAE J2012 are recorded in the ECM
memory (See page DI−13).
If the malfunction does not occurs in 3 trips, the MIL goes off but
the DTCs remain recorded in the ECM memory.
To check the DTCs, connect an OBD II scan tool or
TOYOTA hand−held tester to the DLC3 on the ve-
hicle. The OBD II scan tool or TOYOTA hand−held
tester also enables you to erase the DTCs and
check freeze frame data and various forms of en-
gine data (For operating instructions, see the OBDII
scan tool’s instruction book).
DTCs include SAE controlled codes and Manufac-
turer controlled codes.
SAE controlled codes must be set as prescribed by
the SAE, while Manufacturer controlled codes can
be set freely by the manufacturer within the pre-
scribed limits (See page DI−143).
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Page 721 of 1399

BE4032
BE4033I00021
Normal Code
0.25 sec.
0.25 sec.
ON
OFF
ON
OFF
4 sec. 1.5 sec.
0.5 sec.
2.5 sec.0.5 sec.1.5 sec.
Malfunction codes 11 and 21
Code 11 Code 21
N09348
TOYOTA hand-held tester
TOYOTA Break-out-box
N18670
Instrument Panel Junction Block ECU- B
Fuse
DI-287
-
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
HINT:
If the DTC is not output, inspect the diagnosis circuit (See page
DI-333 )
As an example, the blinking patterns for codes; normal, 11 and
21 are shown in the illustration.
2. ECU TERMINAL VALUES MEASUREMENT BY USING TOYOTA BREAK-OUT-BOX AND TOYOTA HAND-
HELD TESTER
(a) Hook up the TOYOTA break- out- box and TOYOTA hand-held tester to the vehicle.
(b) Read the ECU input/output values by following the prompts on the tester screen.
(c) Please refer to the TOYOTA hand-held tester has a ºSnapshotº function. This records the measured data and
is effective in the diagnosis of intermittent problems.
3. DTC CLEARANCE
(a) After completing repairs, the diagnostic trouble code re- tained in memory can be cleared by removing the ECU-B
fuse for 10 seconds or more, with the ignition switch off.
(b) Check that the normal code is displayed after connecting the fuse.
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Page 726 of 1399
DI5O8−02
I00756
DLC1
Cruise Control Actuator
Actuator Motor
Actuator Magnetic Clutch
Actuator Position Sensor
Cruise Control ECU
Cruise Control Switch
Main Switch
Control Switch
Stop Light Switch
No.1 V ehicle Speed Sensor
Park/Neutral Position Switch
Instrument Panel Fuse Block
GAUGE Fuse
ECU−IG Fuse
ECU− B Fuse
DI−292
−
DIAGNOSTICS CRUISE CONTROL SYSTEM
1996 LAND CRUISER (RM451U)
PARTS LOCATION
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