1996 TOYOTA LAND CRUISER Ect

A00174
ON
EGR Gas Temp.
Sensor 1
2 ECM
5V
E2
19
9
E4
E5 THG
BE6653
FI7054
A00175
ON
EGR Gas Temp.
Sensor ECM
5V
E2
E4 connector
THG
BE6653
FI7099
P22261
−
DIAGNOSTICS ENGINE
DI−81
1996 LAND CRUISER (RM451U)
2 Check for short in harness and ECM.
PREPARATION:
Disconnect the EGR gas temp. sensor connector.
CHECK:
Read EGR gas temp. on the TOYOTA hand−held tester.
OK:
EGR gas temp.: 3.1° C (37.6°F)
OK Replace EGR gas temp. sensor.
NG
3 Check for short in harness or ECM.
PREPARATION:
(a) Remove the instrument panel speaker No.1 panel. (See page SF−65 ).
(b) Disconnect the E4 connector of ECM.
HINT:
EGR gas temp. sensor is disconnected.
CHECK:
Read EGR gas temp. on the TOYOTA hand−held tester.
OK:
EGR gas temp.: 3.1° C (37.6°F)
OK Repair or replace harness or connector.
NG
Check and replace ECM (See page IN−28 ).
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P24665
DI−82
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
4 Check the VSV for EGR (See page DI−69 ).
OK Check EGR valve (See page EC−11).
NG
5 Check operation of the VSV for EGR (See page SF−60).
NG Replace VSV for EGR.
OK
Check for short in harness and connector
between VSV and ECM (See page IN−28).
OBD II scan tool (excluding TOYOTA hand −held tester)
1 Check resistance of EGR gas temp. sensor (See page DI−105).
PREPARATION:
Disconnect EGR gas temp. sensor connector.
CHECK:
Measure resistance between terminals of EGR gas temp. sen-
sor connector.
OK:
Resistance: 2.5 k Ω or more
(Not immediately after driving)
HINT:
If there is short circuit, ohmmeter indicates 200 Ω or less.
NG Replace EGR gas temp. sensor.
OK
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−
DIAGNOSTICS ENGINE
DI−83
1996 LAND CRUISER (RM451U)
2 Check for short in harness and connector between EGR gas temp. sensor and
ECM (See page IN−28 ).
NG Repair or replace harness or connector.
OK
3 Check the VSV for EGR (See page DI−69 , step 5).
OK Check EGR valve (See page EC−11).
NG
4 Check operation of the VSV for EGR (See page SF−60).
NG Replace VSV for EGR.
OK
5 Check for short in harness and connector between VSV and ECM (See page IN−28 ).
NG Repair or replace harness or connector.
OK
Check and replace ECM (See page IN−28 ).
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P23431
Waveform of Oxygen Sensor
Before CatalystNormal
CatalystWaveform of Oxygen Sensor
After Catalyst
DI−84
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0420 Catalyst System Efficiency Below Threshold
CIRCUIT DESCRIPTION
The ECM compares the waveform of the oxygen sensor located before the catal\
yst with the waveform of
the oxygen sensor located after the catalyst to determine whether or not ca\
talyst performance has deterio-
rated.
Air−fuel ratio feedback compensation keeps the waveform of the oxygen sensor\
before the catalyst repeat-
edly changing back and forth from rich to lean.
If the catalyst is functioning normally, the waveform of the oxygen sensor after the catalyst switches back
and forth between rich and lean much more slowly than the waveform of the o\
xygen sensor before the cata-
lyst.
But when both waveforms change at a similar rate, it indicates that catalyst perf\
ormance has deteriorated.


DTC No.DTC Detecting ConditionTrouble Area
P0420
After the engine is warmed up and the vehicle driven for 6
mins. at 30 − 83 km/h (19 − 52 mph), the waveforms of the
heated oxygen sensors, bank 1 sensor 1 and bank1 sensor 2,
have the same amplitude Front exhaust pipe (front catalyst) and rear TWC (rear cata-
lyst)
 Heated oxygen sensor
DI5PM−02
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A00560
Vehicle Speed50 − 65 km/h
Idling
IG SW OFF (1)(2) (3)
Warmed up 5 − 10 mins.
Time
(31 −
40mph)
−
DIAGNOSTICS ENGINE
DI−85
1996 LAND CRUISER (RM451U)
CONFIRMATION ENGINE RACING PATTERN
(1) Connect the OBDII scan tool or TOYOTA hand−held tester to the DLC 3.
(2) Start and warm up the engine with all accessories switched OFF.
(3) Run the vehicle at 50 − 65 km/h (31 − 40 mph) for 5 − 10 mins.
HINT:
If a malfunction exists, the MIL will light up during step (3).
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DI−86
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
INSPECTION PROCEDURE
1 Are there any other codes (besides DTC P0420) being output?
YES Go to relevant DTC chart.
NO
2 Check heated oxygen sensor (bank 1 sensor 1) (See page SF−64 ).
NG Repair or replace.
OK
3 Check heated oxygen sensor (bank 1 sensor 2) (See page SF−64 ).
NG Repair or replace.
OK
Replace front exhaust pipe (front catalyst)
and rear TWC (rear catalyst) (See page
EM−11 0 ).
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P22487
No.1 Vehicle
Speed SensorCombination
Meter ECM
4−pulse
4−pulse
P22473
Combination Meter
3
C13 L−WL
−W8
E7 SPD ECM
5V
E1
From Cruise Control ECU
−
DIAGNOSTICS ENGINE
DI−87
1996 LAND CRUISER (RM451U)
DTC P0500 Vehicle Speed Sensor Malfunction
CIRCUIT DESCRIPTION
The vehicle speed sensor outputs a 4 − pulse signal for every revolution of the rotor shaft, which is rotated
by the transmission output shaft via the driven gear. After this signal is converted into a more precise rectan-
gular wavefrom by the waveform shaping circuit inside the combination meter, it is then transmitted to the
ECM. The ECM determines the vehicle speed based on the frequency of thes\
e pulse signals.
DTC No.DTC Detecting ConditionTrouble Area
P0500
No vehicle speed sensor signal to ECM under conditions (a)
and (b):
(2 trip detection logic)
(a) Park/neutral position switch is OFF.
(b) Vehicle is being driven. Open or short in No.1 vehicle speed sensor circuit
 No.1 vehicle speed sensor
 Combination meter
 ECM
WIRING DIAGRAM
DI5PN−02
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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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