1996 TOYOTA LAND CRUISER Instrument

A00156
ON
Engine Coolant
Temp. Sensor ECM
5V
4
9
2
1
E2
E1
THW
E5
E5
BE6653
FI7055
−
DIAGNOSTICS ENGINE
DI−31
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
HINT:
If DTC is P0110 (Intake Air Temp. Circuit Malfunction), P0115 (Engine Coolant Temp. Circuit Malfunction),
P0120 (Throttle/Pedal Position Sensor/Switch ”A” Circuit Malfunction)\
are output simultaneously, E2 (Sen-
sor Ground) may be open.
1 Connect the OBD II scan tool or TOYOTA hand −held tester, and read value of
engine coolant temperature.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(c) Turn ignition switch ON and push the OBD II scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA hand −held tester.
OK:
Same as actual engine coolant temperature.
HINT:
If there is open circuit, OBD II scan tool or TOYOTA hand−held tester indicates − 40°C (− 40 °F).
If there is short circuit, OBD II scan tool or T OYOTA hand−held tester indicates 140 °C (284 °F) or more.
NG −40°C ( −40° F) ... Go to step 2.
140 °C (284° F) or more ... Go to step 4.
OK
Check for intermittent problems
(See page DI−3 ).
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Connect sensor wire harness terminals together.
(c) Turn ignition switch ON.
CHECK:
Read temp. value on the OBD II scan tool or TOYOTA hand −
held tester.
OK:
Temp. value: 140° C (284°F) or more
OK Confirm good connection at sensor. If OK, replace engine coolant temp. sensor.
NG
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A00157
ONECM
Engine Coolant
Temp. Sensor
5V
E2 E1
2
1
THW E2
THW
E5
E54
9
BE6653
FI7057
P24656
A00158
ON
Engine Coolant
Temp. Sensor ECM
5V
4
9 E2
E1
THW
BE6653
FI7054 E5
E5
DI−32
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
3 Check for open in harness or ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Connect between terminals THW and E2 of ECM connec-
tor.
HINT:
Engine coolant temp. sensor connector is disconnected. Be-
fore checking, do a visual and contact pressure check for the
ECM connector (See page IN−28).
(c) Turn ignition switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA
hand −held tester.
OK:
Temperature value: 140° C (284°F) or more
OK Open in harness between terminals E2 or THW, repair or replace harness.
NG
Confirm good connection at ECM.
If OK, replace ECM (See page IN−28).
4 Check for short in harness or ECM.
PREPARATION:
(a) Disconnect the engine coolant temp. sensor connector.
(b) Turn ignition switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA
hand−held tester.
OK:
Temperature value: − 40° C (− 40°F)
OK Replace engine coolant temp. sensor.
NG
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A00159
ON
Engine Coolant
Temp. Sensor ECM
5V
E2 E1
E5 connector
THW
BE6653
FI7056
P19798
−
DIAGNOSTICS ENGINE
DI−33
1996 LAND CRUISER (RM451U)
5 Check for short in harness or ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Disconnect the E5 connector of ECM.
HINT:
Engine coolant temp. sensor connector is disconnected.
(c) Turn ignition switch ON.
CHECK:
Read temperature value on the OBD II scan tool or TOYOTA
hand −held tester.
OK:
Temperature value: − 40° C (− 40°F)
OK Repair or replace harness or connector.
NG
Check and replace ECM (See page IN−28 ).
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A00483
2
1 3 4R−G
G−B
G−W
BR−B
Throttle Position Sensor
* Closed Throttle
Position Switch
* E5 E5
E5 E5
10 1
11 9 VTA
E2 VCC
IDL 5V
E1 B+
P22422
ECM
FI7052
DI−36
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
If DTCs P0110 (Intake Air Temp. Circuit Malfunction), P0115 (Engine Coolant Temp. Circuit Malfunction),
P0120 (Throttle/Pedal Position Sensor/Switch ”A” Circuit Malfunction)\
are output simultaneously, E2 (Sen-
sor Ground) may be open.
1 Connect the OBD II scan tool or TOYOTA hand −held tester and read the throttle
valve opening percentage.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand−held tester to DLC3.
(c) Turn ignition switch ON and push the OBD II scan tool or TOYOTA hand−held tester main switch ON.
CHECK:
Read the throttle valve opening percentage.
OK:
Throttle valveThrottle valve opening positionexpressed as percentage
Fully openApprox. 75 %
Fully closedApprox. 10 %
OK Check for intermittent problems (See page DI−3 ).
NG
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A00161
ON
BE6653
P24658
(+) (−)
VTA
E2
A00162
ON
VCC E2
(+) (−)
BE6653
P24659
DI−38
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
4 Check voltage between terminals VTA and E2 of ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals VTA and E2 of ECM.
OK:
Throttle valveVoltage
Fully closed0.3 − 0.8 V
Fully open3.2 − 4.9 V
NG Check for open and short in harness and
connector between ECM and throttle
position sensor (VTA line) (See page IN−28).
OK
Check and replace ECM (See page IN−28 ).
5 Check voltage between terminals VCC and E2 of ECM.
PREPARATION:
(a) Remove instrument panel speaker No.1 panel
(See page SF−65 ).
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminals VCC and E2 of ECM con-
nector.
OK:
Voltage: 4.5 − 5.5 V
NG Check and replace ECM (See page IN−28 ).
OK
Check for open in harness and connector
between ECM and sensor (VCC line)
(See page IN−28 ).
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DI−42
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Connect the OBD II scan tool or TOYOTA hand −held tester and read value for
voltage output of heated oxygen sensor).
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(c) Warm up engine to normal operating temp.
CHECK:
Read voltage output of heated oxygen sensor (bank 1 sensor 1) when eng\
ine is suddenly raced.
HINT:
Perform quick racing to 4,000 rpm 3 times using accelerator pedal.
OK:
Heated oxygen sensor (bank 1 sensor 1) output a RICH signal (0.45 V o\
r more) at least once.
OK Check and replace ECM (See page IN−28 ).
NG
2 Check for open and short in harness and connector between ECM and heated\
oxygen sensor (bank1 sensor 1) (See page IN−28 ).
NG Repair or replace harness or connector.
OK
Replace heated oxygen sensor
(bank 1 sensor 1).
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DI−44
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Check for open and short in harness and connector between ECM and heated
oxygen sensor (bank 1 sensor 1) (See page IN−28 ).
NG Repair or replace harness or connector
(See page IN−28 ).
OK
2 Check for heated oxygen sensor (bank 1 sensor 1) data.
PREPARATION:
(a) Remove the fuse cover on the instrument panel.
(b) Connect the OBD II scan tool or TOYOTA hand−held tester to the DLC3.
(c) Warm up engine to normal operating temp.
CHECK:
Read the heated oxygen sensor (bank 1 sensor 1) output voltage and sho\
rt −term fuel trim.
RESULT:
PatternHeated o xygen sensor (bank 1 sensor 1) output voltageShort−term fuel trim
1Lean condition (Changes at 0.55 V or less)Changes at about +20 %
2Rich condition (Changes at 0.4 V or more)Changes at about −20 %
3Except 1 and 2
1, 2 Check fuel trim system (See page DI−51 ).
3
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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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