1996 TOYOTA LAND CRUISER Cruise control

FI0534
DI5OU−02
P22892DLC3TOYOTA
−Hand− Held Tester
−
DIAGNOSTICS ENGINE
DI−3
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 Diagnostic
Trouble Codes (DTC) prescribed by SAE J2012 are
recorded in the ECM memory (See page DI−13).
If the malfunction does not reoccur in 3 trips, the MIL goes off
but the DTC remain recorded in the ECM memory.
To check the DTC, connect the OBD II scan tool or
TOYOTA hand−held tester to Data Link Connector
3 (DLC3) on the vehicle. The OBD II scan tool or
TOYOTA hand−held tester also enables you to
erase the DTCs and check freezed frame data and
various forms of engine data (For operating instruc-
tions, see the OBD II scan tool’s instruction book.).
DTC include SAE controlled codes and manufac-
turer controlled codes. SAE controlled codes must
be set as prescribed by the SAE, while manufactur-
er controlled codes can be set freely by the
manufacturer within the prescribed limits (See DTC
chart on page DI−13).
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DI−12
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
(b) TOYOTA Enhanced Signals.
TOYOTA hand−held tester displayMeasurement ItemNormal Condition*
MISFIRE RPMEngine RPM for first misfire rangeMisfire 0: 0 rpm
MISFIRE LOADEngine load for first misfire rangeMisfire 0: 0 g/r
INJECTORFuel injection time for cylinder No.1Idling: 2.0 − 3.5 ms
IAC STEP POSIntake Air Control Valve step position
Opening position step motor type IAC valveIdling: 10 − 50 step
STARTER SIGStarter SignalCranking: ON
CTP SWClosed Throttle Position Switch SignalThrottle Fully Closed: ON
A/C SIGA/C Switch SignalA/C ON: ON
PNP SWPark/Neutral Position Switch SignalP or N Position: ON
STOP LIGHT SWStop Light Switch SignalStop light switch ON: ON
FC IDLFuel Cut Idle: Fuel cut when throttle valve fully
closed, during decelerationFuel cut operating: ON
FC TAUFuel Cut TAU: Fuel cut during very light loadFuel cut operating: ON
CYL#1 − CYL#6Ratio of revolution variation for each cylinder
when variation is large0%
IGNITIONIgnition rate for all cylinders every 1,000 revolu-
tions0 − 3,000 rpm
EGRT GASEGR Gas Temp. Sensor V alueEGR not operating: Temp. between intake air
temp. and engine coolant temp.
EGR SYSTEMEGR System Operating ConditionIdling: OFF
FUEL PRES UP VSVFuel Pressure Up VSV SignalHigh temp. restarting: ON
FUEL PUMPFuel Pump SignalIdling: ON
TOTAL FT B1Total Fuel Trim Bank 1: Average value for fuel
trim system of bank 1Idling: 0.8 − 1.2 V
O2 LR B1, S1
Oxygen Sensor Lean Rich Bank 1, Sensor 1
Response time for oxygen sensor output to
switch from lean to rich
Idling after warmed up: 0 − 1,000 msec.
O2 RL B1, S1
Oxygen Sensor Rich Lean Bank 1, Sensor 1
Response time for oxygen sensor output to
switch from rich to lean
Idling after warmed up: 0 − 1,000 msec.
∗: If no conditions are specifically stated for ”ldling”, it means t\
he shift lever is at N or P position, the A/C switch
is OFF and all accessory switches are OFF.
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DI5OV−03
−
DIAGNOSTICS ENGINE
DI−13
1996 LAND CRUISER (RM451U)
DIAGNOSTIC TROUBLE CODE CHART
HINT:
Parameters listed in the chart may not be exactly the same as your reading due to \
the type of instrument
or other factors.
If a malfunction code is displayed during the DTC check in check mode, che\
ck the circuit for that code listed
in the table below. For details of each code, turn to the page referred to under the ’’See page ’’ for the respe-
cire ’’DTC No.’’ in the DTC chart.
DTC No.
(See Page)Detection ItemTrouble AreaMILMemory
P0100
( DI−20 )Mass Air Flow Circuit
MalfunctionOpen or short in mass air flow meter circuit
 Mass air flow meter
 ECM
 *1
P0101
( DI−25 )Mass Air Flow Circuit
Range/Performance
Problem
Mass air flow meter *1
P0110
( DI−26 )Intake Air Temp. Circuit
MalfunctionOpen or short in intake air temp. sensor circuit
 Intake air temp. sensor
 ECM
 *1
P0115
( DI−30 )Engine Coolant Temp. Circuit
MalfunctionOpen or short in engine coolant temp. sensor circuit
 Engine coolant temp. sensor
 ECM
 *1
P0116
( DI−34 )Engine Coolant Temp. Circuit
Range/Performance ProblemEngine coolant temp. sensor
 Cooling system *1
P0120
( DI−35 )Throttle/Pedal Position
Sensor/Switch ”A” Circuit
MalfunctionOpen or short in throttle position sensor circuit
 Throttle position sensor
 ECM
 *1
P0121
( DI−39 )Throttle/Pedal Position
Sensor/Switch ”A” Circuit
Range/Performance Problem
Throttle position sensor *1
P0125
( DI−40 )Insufficient Coolant Temp. for
Closed Loop Fuel Control Open or short in heated oxygen sensor circuit
 Heated oxygen sensor *1
P0130
( DI−43 )Heated Oxygen Sensor Circuit
Malfunction (Bank 1 Sensor 1)Heated oxygen sensor
 Fuel trim malfunction *1
P0133
( DI−46 ) Heated Oxygen Sensor Circuit
Slow Response
(Bank 1 Sensor 1)
Heated oxygen sensor *1
P0135
( DI−47 ) Heated Oxygen Sensor Heater
Circuit Malfunction
(Bank 1 Sensor 1)Open or short in heater circuit of heated oxygen sensor
 Heated oxygen sensor heater
 ECM
 *1
P0136
( DI−49 )Heated Oxygen Sensor Circuit
Malfunction
(Bank 1 Sensor 2)
Heated oxygen sensor *1
P0141
( DI−47 ) Heated Oxygen Sensor Heater
Circuit Malfunction
(Bank 1 Sensor 2)
Same as DTC No. P0135 *1
*1: MIL lights up
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−
DIAGNOSTICS ENGINE
DI−15
1996 LAND CRUISER (RM451U)
DTC No.
(See Page)
Detection ItemTrouble Area*MILMemory
P0420
( DI−84 )Catalyst System Efficiency
Below Threshold Three− way catalytic convertor
 Open or short in heated oxygen sensor circuit
 Heated oxygen sensor

P0500
( DI−87 )Vehicle Speed Sensor
Malfunction
Combination meter
 Open or short in speed sensor circuit
 ECM
 Vehicle speed sensor

P0505
( DI−89 )Idle Control System
Malfunction
IAC valve is stuck or closed
 Open or short in IAC valve circuit
 Open or short A/C signal circuit
 Air intake (hose loose)

P0510
( DI−93 )Closed Throttle Position
Switch MalfunctionOpen in closed throttle position switch circuit
 Closed throttle position switch
 ECM

P1300
( DI−97 )Igniter Circuit Malfunction
Open or short in IGF or IGT circuit from igniter to ECM
 Igniter
 ECM

P1335
( DI−102 )Crankshaft Position Sensor
Circuit Malfunction
(during engine running)
Open or short in crankshaft position sensor circuit for NE sig-
nal
 Crankshaft position sensor for NE signal
 Starter
 ECM
−
P1500
( DI−103 )Stater signal circuit MalfunctionOpen or short in starter signal circuit
 ECM−
P1600
( DI−105 )ECM BATT MalfunctionOpen in back up power source circuit
 ECM
P1605
( DI−107 )Knock Control CPU MalfunctionECM
P1780
( DI−108 )Park/Neutral Position Switch
MalfunctionShort in park/neutral position switch circuit
 Park/neutral position switch
 ECM

*: −  MIL does not light up,   MIL lights up
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DI5OY−03
−
DIAGNOSTICS ENGINE
DI−19
1996 LAND CRUISER (RM451U)
PROBLEM SYMPTOMS TABLE
When the malfunction code is not confirmed in the DTC check and the problem \
still can not be confirmed
in the basic inspection, then proceed to this step and perform troubleshooting according to the numbered
order given in the table below.
SymptomSuspect AreaSee page
Engine does not crank (Does not start)1. Starting systemST−16
No initial combustion (Does not start)1. ECM power source circuit
2. Fuel pump control circuitDI−11 0
DI−11 5
No complete combustion (Does not start)1. Fuel pump control circuitDI−11 5
Engine cranks normally (Difficult to start)
1. Starter signal circuit
2. Fuel pump control circuit
3. CompressionDI−103
DI−11 5 EM−3
Cold engine (Difficult to start)1. Starter signal circuit
2. Fuel pump control circuitDI−103DI−11 5
Hot engine (Difficult to start)
1. Starter signal circuit
2. Fuel pressure control circuit
3. Fuel pump control circuitDI−103
DI−125DI−11 5
High engine idle speed (Poor idling)1. A/C signal circuit
2. ECM power source circuitAC−5
DI−11 0
Low engine idle speed (Poor idling)1. A/C signal circuit
2. Fuel pump control circuitAC−5
DI−11 5
Rough idling (Poor idling)1. Compression
2. Fuel pump control circuitEM−3
DI−11 5
Hunting (Poor idling)1. ECM power source circuit
2. Fuel pump control circuitDI−11 0
DI−11 5
Hesitation/Poor acceleration (Poor driveability)1. Fuel pump control circuit
2. A/T faultyDI−11 5
DI−147
Surging (Poor driveability)1. Fuel pump control circuitDI−11 5
Soon after starting (Engine stall)1. Fuel pump control circuitDI−11 5
During A/C operation (Engine stall)1. A/C signal circuit
2. Engine control module (ECM)AC−5
IN−18
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DI5OZ−02
A00152
Output Voltage
Power Transistor
B+
Thermistor
Platinum Hot Wire
A B
Thermistor Platinum Hot Wire
FI6929 P22263
DI−20
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
CIRCUIT INSPECTION
DTC P0100 Mass Air Flow Circuit Malfunction
CIRCUIT DESCRIPTION
The mass air flow meter uses a platinum hot wire. The hot wire air flow met\
er consists of a platinum hot wire,
thermistor and a control circuit installed in a plastic housing. The hot wire air f\
low meter works on the principle
that the hot wire and thermistor located in the intake air bypass of the hou\
sing detect any changes in the
intake air temperature.
The hot wire is maintained at the set temperature by controlling the curren\
t flow through the hot wire. This
current flow is then measured as the output voltage of the air flow mete\
r.
The circuit is constructed so that the platinum hot wire and thermistor pro\
vide a bridge circuit, with the power
transistor controlled so that the potential of ”A” and ”B” remains equ\
al to maintain the set temperature.
DTC No.DTC Detecting ConditionTrouble Area
P0100Open or short in mass air flow meter circuit with engine
speed 4,000 rpm or less. Open or short in mass air flow meter circuit
 Mass air flow meter
 ECM
If the ECM detects DTC” P0100” it operates the fail safe function, k\
eeping the ignition timing and injection
volume constant and marking it possible to drive the vehicle.
HINT:
After confirming DTC P0100 use the OBD II scan tool or TOYOTA hand −held tester to confirm the mass air
flow ratio from ”CURRENT DATA”.
Mass Air Flow Value (gm/sec.)Malfunction
Approx. 0Mass air flow meter power source open
 VG circuit open or short
439.0 or moreE21 circuit open
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FI6571
Throttle Position
SensorVCCVTA
IDLE2 ECM
5V
B+
−
DIAGNOSTICS ENGINE
DI−35
1996 LAND CRUISER (RM451U)
DTC P0120 Throttle/Pedal Position Sensor/Switch ”A”
Circuit Malfunction
CIRCUIT DESCRIPTION
The throttle position sensor is mounted in the throttle body and
detects the throttle valve opening angle.
When the throttle valve is fully closed, the IDL contacts in the
throttle position sensor are on, so the voltage at the terminal IDL
of the ECM becomes 0 V. At this time, a voltage of approximate-
ly 0.3 − 0.8 V is applied to terminal VTA of the ECM. When the
throttle valve is opened, the IDL contacts go off and thus the
power source voltage of approximately 12 V in the ECM is ap-
plied to the terminal IDL of the ECM. The voltage applied to the
terminal VTA of the ECM increases in proportion to the opening
angle of the throttle valve and becomes approximately 3.2 − 4.9
V when the throttle valve is fully opened. The ECM judges the
vehicle driving conditions from these signals input from termi-
nals VTA and IDL, and uses them as one of the conditions for
deciding the air− fuel ratio correction, power increase correction
and fuel −cut control etc.
DTC No.DTC Detecting ConditionTrouble Area
P0120
Condition (a) or (b) continues
(a) VTA < 0.1 V, and closed throttle position switch is OFF
(b) VTA > 4.9 VOpen or short in throttle position sensor circuit
 Throttle position sensor
 ECM
HINT:
If there is open circuit in IDL line, DTC P0120 does not indicate.
After confirming DTC P0120 use the OBD II scan tool or TOYOTA hand−held tester to confirm the
throttle valve opening percentage and closed throttle position switch condition\
.
Throttle valve opening position
expressed as percentage
Trouble Area
Throttle valve fully closedThrottle valve fully open
0 %0 %VCC line open
VTA line open or short
Approx. 99 %Approx. 100 %E2 line open
DI5P7−02
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P21242 FI7210A00027
Atmosphere
Flange
Platinum Electrode
Solid Electrolyte
(Zirconia Element)
Platinum Electrode
Heater
Coating (Ceramic)
Exhaust GasCover Ideal Air−
Fuel Mixture
Output Voltage
Richer − Air Fuel Ratio − Leaner
DI−40
−
DIAGNOSTICS ENGINE
1996 LAND CRUISER (RM451U)
DTC P0125 Insufficient Coolant Temp. for Closed Loop
Fuel Control
CIRCUIT DESCRIPTION
To obtain a high purification rate for the CO, HC and NOx components of th\
e exhaust gas, a three −way cata-
lytic converter is used, but for the most efficient use of the three −way catalytic converter, the air−fuel ratio
must be precisely controlled so that it is always close to the stoichiom\
etric air −fuel ratio.
The oxygen sensor has the characteristic where by its output voltage change\
s suddenly in the vicinity of the
stoichiometric air −fuel ratio. This characteristic is used to detect the oxygen concentrati\
on in the exhaust
gas and provide feedback to the computer for control of the air −fuel ratio.
When the air −fuel ratio becomes LEAN, the oxygen concentration in the exhaust increas\
es and the oxygen
sensor informs the ECM of the LEAN condition (small electromotive force: 0 V)\
.
When the air −fuel ratio is RICHER than the stoichiometric air −fuel ratio the oxygen concentration in the ex-
haust gas in reduced and the oxygen sensor informs the ECM of the RICH condit\
ion (large electromotive
force: 1 V). The ECM judges by the electromotive force from the oxygen \
sensor whether the air −fuel ratio
is RICH or LEAN and controls the injection time accordingly. However, if malfunction of the oxygen sensor
causes output of abnormal electromotive force, the ECM is unable to perform acc\
urate air −fuel ratio control.
The heated oxygen sensors include a heater which heats the zirconia element\
. The heater is controlled by
the ECM. When the intake air volume is low (the temp. of the exhaust gas i\
s low) current flows to the heater
to heat the sensor for accurate oxygen concentration detection.
DTC No.DTC Detecting ConditionTrouble Area
P0125
After the engine is warmed up, heated oxygen sensor (bank 1
sensor 2) output does not indicate RICH even once when
conditions (a), (b) and (c) continue for at least 1.5 min.
(a) Engine speed: 1,500 rpm or more
(b) Vehicle speed: 40 − 100 km/h (25 − 62 mph)
(c) Closed throttle position switch: OFF
 Open or short in heated oxygen sensor (bank 1 sensor 1)
circuit
 Heated oxygen sensor (bank1 sensor 1)
DI5P9−02
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