1998 TOYOTA LAND CRUISER engine air intake

- DIAGNOSTICSENGINE
DI-69
262 Author
: Date
:
2004 LAND CRUISER (RM1071U)
MONITOR DESCRIPTION
The ECM monitors the sensor voltage and uses this value to calculate the intake air temperature. When the
sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the IAT
(Intake Air Temperature) sensor and sets a DTC.
Example:
When the sensor voltage output equal to -40C (-40F), or more than 140C (284F).
MONITOR STRATEGY
P0110Intake air temperature sensor range check
(Fluttering)
Related DTCsP0112Intake air temperature sensor range check
(Low resistance)
P0113Intake air temperature sensor range check
(High resistance)
Required sensors/componentsIntake air temperature sensor
Frequency of operationContinuous
Duration0.5 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever the follow-
ing DTCs are not presentSee ºList of disable a monitorº (on page DI-3)
The typical enabling condition is not avail-
able-
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P0110:
Intake air temperature sensor resistance
(Intake air temperature)Less than 98.5 W, or more than 156 kW
(More than 140C (284F), or less than -40C (-40F)
P0112:
Intake air temperature sensor resistance
(Intake air temperature)Less than 98.5 W
(More than 140C (284F))
P0113:
Intake air temperature sensor resistance
(Intake air temperature)More than 156 kW
(Less than -40C (-40F))
COMPONENT OPERATING RANGE
ParameterStandard Value
Intake air temperature sensor resistance98.5 W (140C (284F)) to 156 kW (-40C (-40F))

- DIAGNOSTICSENGINE
DI-71
264 Author
: Date
:
2004 LAND CRUISER (RM1071U)
1 Connect OBD II scan tool or hand-held tester, and read value of intake air tem-
perature.
PREPARATION:
(a) Connect the OBD II scan tool or the hand-held tester to the DLC3.
(b) Turn the ignition switch ON and push the OBD II scan tool or the hand-held tester main switch ON.
(c) When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / ALL / INTAKE AIR.
CHECK:
Read the temperature value on the OBD II scan tool or the hand-held tester.
OK:
Same as actual intake air temperature.
RESULT:
Temperature DisplayedProceed to
-40°C (-40°F)A
140°C (284°F) or moreB
OK (Same as present temperature)C
HINT:

If there is an open circuit, the OBD II scan tool or the hand-held tester indicates -40°C (-40°F).

If there is a short circuit, the OBD II scan tool or the hand-held tester indicates 140°C (284°F) or more.
B Go to step 4.
C Check for intermittent problems
(See page DI-3).
A

- DIAGNOSTICSENGINE
DI-75
268 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0115 Engine Coolant Temperature Circuit
DTC P0117 Engine Coolant Temperature Circuit Low
Input
DTC P0118 Engine Coolant Temperature Circuit High
Input
CIRCUIT DESCRIPTION
A thermistor is built in the Engine Coolant Temperature (ECT) sensor and changes the resistance value ac-
cording to the engine coolant temperature.
The structure of the sensor and connection to the ECM is the same the Intake Air Temperature (IAT) sensor.
HINT:
If the ECM detects the DTC ºP0115, P0117 or P0118º, it operates the fail-safe function in which the ECT
is assumed to be 80 C (176 F).
DTC No.Proceed toDTC Detection ConditionTrouble Area
P0115Step 1
Open or short in engine cool-
ant temperature sensor circuit
for 0.5 sec.
P0117Step 4
Short in engine coolant tem-
perature sensor circuit for 0.5
sec.
Open or short in engine coolant temperature sensor circuit

Engine coolant temperature sensor

ECM
P0118Step 2
Open in engine coolant tem-
perature sensor circuit for 0.5
sec.
HINT:
After confirming DTC ºP0115, P0117 or P0118,º use the OBD II scan tool or the hand-held tester to confirm
the engine coolant temperature from the DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL.
Temperature DisplayedMalfunction
-40°C (-40°F)Open circuit
140°C (284°F) or moreShort circuit
MONITOR DESCRIPTION
The ECT (Engine Coolant Temperature) sensor is used to monitor the engine coolant temperature. The ECT
sensor has a thermistor that varies its resistance depending on the temperature of the engine coolant. When
the coolant temperature is low, the resistance in the thermistor increases. When the temperature is high, the
resistance drops. The variations in resistance are reflected in the voltage output from the sensor.
The ECM monitors the sensor voltage and uses this value to calculate the engine coolant temperature.
When the sensor output voltage deviates from the normal operating range, the ECM interprets this as a fault
in the ECT sensor and sets a DTC.
Example:
When the ECM calculates that the ECT is less than -40C (-40F), or more than 140C (284F), and if either
the condition continues for 0.5 sec. or more, the ECM will set a DTC.
DI1LF-13

DI-82
- DIAGNOSTICSENGINE
275 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0116 Engine Coolant Temperature Circuit Range/
Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI-75.
DTC No.DTC Detecting ConditionTrouble Area
P0116
If the engine coolant temperature was 35°C (95°F) or more but
less than 60°C (140°F) when the engine is started, and if
conditions (a) and (b) are met:
(a) Vehicle has accelerated and decelerated.
(b) Engine coolant temperature remains within 3°C (5.4°F) of
the initial engine coolant temperature (2 trip detection logic)

Engine coolant temperature sensorP0116
If the engine coolant temperature is more than 60°C (140°F)
when the engine is started and the vehicle has accelerated
and decelerated

If the engine coolant temperature sensor records a tempera-
ture variation below 1°C (1.8°F) successively 6 times (6 trip
detection logic)
Engine coolant temperature sensor
MONITOR DESCRIPTION
The ECT (Engine Coolant Temperature) sensor is used to monitor the engine coolant temperature. The ECT
sensor has a thermistor that varies its resistance depending on the temperature of the engine coolant. When
the coolant temperature is low, the resistance in the thermistor increases. When the temperature is high, the
resistance drops. The variations in resistance are reflected in the voltage output from the sensor. The ECM
monitors the sensor voltage and uses this value to calculate the engine coolant temperature. When the sen-
sor output voltage deviates from the normal operating range, the ECM interprets this as a fault in the ECT
sensor and sets a DTC.
Examples:
(1) Upon starting the engine, the ECT is between 35°C (95°F) and 60°C (140°F). If after driving for 250 sec.,
the ECT still remains within 3°C (5.4°F) of the starting temperature, a DTC will be set (2 trip detection logic).
(2) Upon starting the engine, the ECT is over 60°C (140°F). If after driving for 250 sec., the ECT still remains
within 1°C (1.8°F) of the starting temperature, a DTC will be set (6 trip detection logic).
MONITOR STRATEGY
Related DTCsP0116Engine coolant temperature sensor range check
(Stuck)
Main sensors/componentsEngine coolant temperature sensor
Required sensors/componentsRelated sensors/componentsIntake air temperature sensor, Crankshaft
position sensor, Mass air flow meter
Frequency of operationContinuous
Duration250 sec.
MIL operation2 driving cycles (When temperature is fixed between 35C (95F) and 60C (140F))
6 driving cycles (When temperature is fixed at 60C (140F) or more)
Sequence of operationNone
DI1LG-15

- DIAGNOSTICSENGINE
DI-83
276 Author
: Date
:
2004 LAND CRUISER (RM1071U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever the follow-
ing DTCs are not presentSee ºList of disable a monitorº (on page DI-3)
Case 1 (When temperature is fixed between 35C (95F) and 60C (140F)):
Cumulative idle off period250 sec.-
Speed increase 30 km/h (19 mph) or more10 times-
Engine coolant temperature35C (95F)60C (140F)
Intake air temperature-6.7C (20F)-
Case 2 (When temperature is fixed at 60C (140F) or more):
Engine coolant temperature at engine
start60C (140F)-
Intake air temperature-6.7C (20F)-
Stop and goOnce or more (Stop for 20 sec. or more and accelerate to more than 70 km/h (43 mph)
with in 40 sec.)
Steady driving and stop *Once or more
*: Vehicle is driven by 65 km/h (40 mph) or more for 30 sec. or more and the vehicle speed reaches 70 km/h
(44 mph). The vehicle is decelerated from 65 km/h (40 mph) to 3 km/h (2 mph) or less within 35 sec. and
stopped for 10 sec.
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Case1 (When temperature is fixed between 35C (95F) and 60C (140F)):
Change of engine coolant temperature valueLess than 3C (5.4F)
Case2 (When temperature is fixed at 60C (140F) or more):
Change of engine coolant temperature value1C (1.8F) or less
COMPONENT OPERATING RANGE
Standard Value
Engine coolant temperature changes with the actual engine coolant temperature.
INSPECTION PROCEDURE
HINT:

If DTC P0115, P0116, P0117, P0118 and P0125 are output simultaneously, ECT sensor circuit may
be open or shorted. Perform the troubleshooting of DTC P0115, P0117 or P0118 first.

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records
the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can
help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel
ratio was lean or rich, as well as other data from the time when a malfunction occurred.
Replace engine coolant temperature sensor.

- DIAGNOSTICSENGINE
DI-99
292 Author
: Date
:
2004 LAND CRUISER (RM1071U)
DTC P0125 Insufficient Coolant Temperature
for Closed Loop Fuel Control
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI-75.
DTC No.DTC Detection ConditionTrouble Area
If THW or THA is less than -6.6°C (20°F) at engine start
and 20 min. or more after starting engine, engine coolant
temp. sensor value is 20°C (68°F) or less (2 trip detection
logic)
P0125
If THW and THA is between -6.6°C (20°F) and 10°C
(50°F)
at engine start, 5 min. or more after starting engine and
engine coolant temp. sensor value is 20°C (68°F) or less (2
trip detection logic)

Cooling system

Engine coolant temperature sensor

Thermostat
If THW and THA greater than 10°C (50°F) at engine start
and 2 min. or more after starting engine, engine coolant
temp. sensor value is 20°C (68°F) or less (2 trip detection
logic)
MONITOR DESCRIPTION
The ECT (Engine Coolant Temperature) sensor is used to monitor the temperature of the engine coolant.
The resistance of the sensor varies with the actual coolant temperature. The ECM applies a voltage to the
sensor and the varying resistance of the sensor causes the signal voltage to vary. The ECM monitors the
ECT signal voltage after engine start-up.
If, after sufficient time has passed, the sensor still reports that the
engine is not warmed up enough for closed-loop fuel control after sufficient time has passed, the ECM inter-
prets this as a fault in the sensor or cooling system and sets a DTC.
Example:
The engine coolant temperature was 0C (32F) at engine start. After 5 min. running time, the ECT sensor
still indicates that the engine is not warmed up enough to begin air fuel ratio feedback control of the air-fuel
ratio. The ECM interprets this as a fault in the sensor or cooling system and will set a DTC.
MONITOR STRATEGY
Related DTCsP0125Insufficient coolant temperature for closed loop
fuel control
Required sensors/componentsMain sensors/componentsEngine coolant temperature sensor, Cooling sys-
tem, Thermostat
Required sensors/com onents
Related sensors/componentsMass air flow meter
Frequency of operationContinuous
2 min. (at engine start, engine coolant or intake air temperature of 10°C (50°F) or more)
Duration
2 min. (at engine start, engine coolant or intake air tem erature of 10C (50F) or more)
5 min. (at engine start, engine coolant or intake air temperature of -6.6°C (20°F) to 10°C (50°F))Duration5 min. (at engine start, engine coolant or intake air tem erature of 6.6C (20F) to 10C (50F))
20 min. (at engine start, engine coolant or intake air temperature of less than -6.6°C (20°F))
MIL operation2 driving cycles
Sequence of operationNone
DIBSS-02

- DIAGNOSTICSENGINE
DI-103
296 Author
: Date
:
MONITOR STRATEGY
Related DTCsP0128Thermostat
Rid / t
Main sensors/componentsEngine coolant temperature sensor, Engine
cooling system, Thermostat
Required sensors/components
Related sensors/componentsIntake air temperature sensor, Vehicle speed
sensor
Frequency of operationOnce per drive cycle
Duration15 min.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever the follow-
ing DTCs are not presentSee ºList of disable a monitorº (on page DI-3)
Battery voltage11.0 V-
Intake air temperature (at engine start)-10C (14F)35C (95F)
Engine coolant temperature
(at engine start)-10C (14F)35C (95F)
Difference between intake air temperature
and engine coolant temperature (at engine
start)
-15C (-27F)7C (12.6F)
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Duration period of both A and B5 sec. or more
A Estimated engine coolant temperature75C (167F) or more
B Engine coolant temperature sensor output valueLess than 75C (167F)
MONITOR RESULT
The detailed information is described in CHECKING MONITOR STATUSº (see page DI-3).

TID (Test Identification) is assigned to each emission-related component.

TLT (Test Limit Type):
If TLT is 0, the component is malfunctioning when the test value is higher than the test limit.
If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.

CID (Component Identification) is assigned to each test value.

Unit Conversion is used to calculate the test value indicated on generic OBD scan tools.
TID $08: Thermostat
TLTCIDUnit ConversionDescription of Test ValueDescription of Test Limit
1$01Multiply by 0.625 and sub-
tract 40 (C)ECT sensor output when estimated ECT reaches malfunction criteri-
onMalfunction criterion

- DIAGNOSTICSENGINE
DI-1 19
312 Author
: Date
:
2004 LAND CRUISER (RM1071U)
MONITOR STRATEGY
RltdDTC
P0133Front heated oxygen sensor response monitor
(Bank 1)
Related DTCs
P0153Front heated oxygen sensor response monitor
(Bank 2)
Main sensors/componentsFront heated oxygen sensor
Required sensors/componentsRelated sensors/componentsCrank position sensor, Vehicle speed sensor,
Mass air flow meter
Frequency of operationOnce per drive cycle
DurationWithin 60 sec.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever the follow-
ing DTCs are not presentSee ºList of disable a monitorº (on page DI-3)
Frequency idle condition:
There is history that the following condi-
tions were met for 20 sec.A and B
A. Vehicle speed40 km/h (25 mph)-
B. Engine speed900 rpm-
IdleON
Vehicle speed-5 km/h (3 mph)
Fuel system statusClosed loop
Time after engine start120 sec.-
Engine coolant temperature40°C (104°F)-
Frequency cruise condition:
There is history that the following condi-
tions were met for 20 sec.A and B
A. Vehicle speed40 km/h (25 mph)-
B. Engine speed900 rpm-
Intake air amount3 g/sec.13 g/sec.
Time after engine start120 sec.-
IdleOFF
Fuel system statusClosed loop
Engine speed1,000 rpm3,500 rpm
Engine coolant temperature70°C (158°F)-
Slow slope condition:
Both of the following condition were met
for 20 sec.A and B
A. Vehicle speed40 km/h (25 mph)-
B. Engine speed900 rpm-
Time after engine start120 sec.-
IdleON
Vehicle speed-5 km/h (3 mph)