1998 TOYOTA LAND CRUISER coolant temperature
[x] Cancel search: coolant temperaturePage 1149 of 3115
DI-100
- DIAGNOSTICSENGINE
293 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 table (on page DI-3)
Fuel cutOFF
EngineRunning
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Time until ºengine coolant temperatureº detection temperature reaches feedback start temperature
When the temperature at the time of engine starting is
10°C (50°F) or moreEngine coolant temperature is less than ºclosed-loop enable temperatureº
when 2 min. or more after engine start
When the temperature at the time of engine starting is
º-6.6°C (20°F)º to º10°C (50°F)ºEngine coolant temperature is less than ºclosed-loop enable temperatureº
when 5 min. or more after engine start
When the temperature at the time of engine starting is
-6.6°C (20°F) or lessEngine coolant temperature is less than ºclosed-loop enable temperatureº
when 20 min. or more after engine start
INSPECTION PROCEDURE
HINT:
If DTC P0115, P0116, P0117, P0118 and P0125 are output simultaneously, engine coolant tempera-
ture sensor circuit may be open or short. 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.
1 Are there any other codes (besides DTC P0125) being output?
PREPARATION:
(a) Connect the hand-held tester or the OBD II scan tool to the DLC3.
(b) Turn the ignition switch ON and push the hand-held tester or OBD II scan tool main switch ON.
(c) When using hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / CURRENT CODES.
CHECK:
Read the DTCs using the hand-held tester or the OBD II scan tool.
RESULT:
Display (DTC output)Proceed to
P0125A
ºP0125º and other DTCsB
HINT:
If any other codes besides ºP0125º are output, perform the troubleshooting for those DTCs first.
B Go to relevant DTC chart (See page DI-36).
A
Page 1150 of 3115
- DIAGNOSTICSENGINE
DI-101
294 Author: Date:
2004 LAND CRUISER (RM1071U)
2 Inspect thermostat (See page CO-12).
NG Replace thermostat
(See page CO-1 1).
OK
3 Check cooling system.
CHECK:
Check that there is detect cooling system which causes overcool, such as abnormal radiator fan operation,
modified cooling system and so on.
NG Repair or replace cooling system.
OK
Replace engine coolant temperature sensor.
Page 1151 of 3115
A20488A21045
Threshold
(75C (167F))Estimated ECT
5 sec.
Indicated coolant temp. reading
DTC set (after 2 driving cycle) ECT
Time DI-102
- DIAGNOSTICSENGINE
295 Author: Date:
DTC P0128 Coolant Thermostat (Coolant Temperature
Below Thermostat Regulating Temperature)
HINT:
This is the purpose of ºthermostatº malfunction detection.
CIRCUIT DESCRIPTION
If the engine coolant temperature does not reach 75°C (167°F) despite sufficient warm-up time has
elapsed.
DTC No.DTC Detection conditionTrouble Area
P0128
Condition (a), (b) and (c) are met:
(a) Cold start
(b) After sufficient warm-up time has elapsed
(c) Engine coolant temperature greater than 75°C (167°F)Thermostat
Cooling system
Engine coolant temperature sensor
ECM
MONITOR DESCRIPTION
The ECM estimates the coolant temperature based on starting temperature, engine loads, and engine
speeds. The ECM then compares the estimated temperature with the actual ECT (Engine Coolant Tempera-
ture). When the estimated coolant temperature reaches 75C (167F), the ECM checks the actual ECT. If
the actual ECT is less than 75C (167F), the ECM will interpret this as a fault in the thermostat or engine
cooling system and set a DTC.
DIC25-01
Page 1152 of 3115
- 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
Page 1168 of 3115
- 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)
Page 1169 of 3115
DI-120
- DIAGNOSTICSENGINE
313 Author: Date:
2004 LAND CRUISER (RM1071U) Fuel system status
Closed loop
Engine coolant temperature40°C (104°F)-
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Frequency idle condition
Time required by the sensor's output voltage to change in
one RICH-LEAN cycle5.6 sec. or more
Frequency cruise condition
Time required by the sensor's output voltage to change in
one RICH-LEAN cyclea specific time or more
Slow slope condition
Both of the following conditions were metA and B
A. Number of judgment made3 times
B. Following conditions were met(a) or (b)
(a) Average lean to rich response time0.9 sec. or more
(b) Average rich to lean response time0.9 sec. or more
COMPONENT OPERATING RANGE
ParameterStandard value
Voltage output from heated oxygen sensorQuickly fluctuates between 0.4 and 0.55 V
O2S TEST RESULT
Refer to page DI-3 for detailed information.
Front HO2S slow slope monitor
If the HO2S sensor voltage is out of the standard value, the ECM interprets this as a malfunction.
TEST IDDescription of TEST DATAConversion FactorUnit
$03
(Test constant)
Low sensor voltage for response
time calculation
N/AV
$04
(Test constant)
High sensor voltage for response
time calculation
N/AV
If the time required to change is out of the standard value, the ECM interprets this as a malfunction.
TEST IDDescription of TEST DATAConversion FactorUnit
$31Time to change from Lean (0.4
V) to Rich (0.55 V)N/Asec.
$32Time to change from Rich (0.55
V) to Lean (0.4 V)N/Asec.
Front HO2S frequency monitor (idling)
If the $38 is out of the standard value, the ECM interprets this as a malfunction.
TEST IDDescription of TEST DATAConversion FactorUnit
$38
Response time of heated oxygen
sensor's output voltage in one
RICH-LEAN cycle
N/Asec.
Page 1178 of 3115
- DIAGNOSTICSENGINE
DI-129
322 Author: Date:
2004 LAND CRUISER (RM1071U)
DTC P0134 Oxygen Sensor Circuit No Activity Detected
(Bank 1 Sensor 1)
DTC P0154 Oxygen Sensor Circuit No Activity Detected
(Bank 2 Sensor 1)
CIRCUIT DESCRIPTION
Refer to DTC P0031 on page DI-49.
DTC No.DTC Detecting ConditionTrouble Area
P0134
P0154
After the engine is warmed up, heated oxygen sensor (bank 1,
sensor 1) output does not indicate RICH (more than 0.45 V)
even once when the following conditions continue for 65 sec.
or more:
(a) Engine speed: 1,400 rpm or more
(b) Vehicle speed: 25 to 81 mph (40 to 130 km/h) or more
(c) Throttle valve does not fully closed
(d) 180 sec. or more after starting engine
(e) Engine coolant temperature more than 40°C (104°F)
Open or short in heated oxygen sensor circuit
Heated oxygen sensor
Heated oxygen sensor heater
EFI or ECD relay
Air induction system
Fuel pressure
PCV hose connection
PCV valve and hose
Injector
Gas leakage on exhaust system
PCV piping
ECM
HINT:
Bank 1 refers to bank that includes cylinder No. 1.
Bank 2 refers to bank that does not includes cylinder No. 1.
Sensor 1 refers to the sensor closer to the engine assembly.
After confirming DTC P0134 and P0154, check the output voltage of the heated oxygen sensor in the
"DIAGNOSIS / ENHANCE OBD II / DATA LIST / ALL" using the OBD II scan tool or the hand-held tester.
If output voltage of the heated oxygen sensor is always less than 0.1 V, heated oxygen sensor circuit
may be open or short.
MONITOR DESCRIPTION
The ECM uses the heated oxygen sensor to optimize the air-fuel mixture in closed-loop fuel control. This
control helps decrease exhaust emissions by providing the catalyst with a nearly stoichiometric mixture.
The sensor detects the oxygen level in the exhaust gas and the ECM uses this data to control the air-fuel
ratio. The sensor output voltage ranges from 0 V to 1 V. If the signal voltage is less than 0.4 V, the air-fuel
ratio is LEAN. If the signal voltage is more than 0.55 V, the air-fuel ratio is RICH. If the conditions for the
closed-loop fuel control are met and after a specified time-period, the sensor's output signal never indicates
RICH, the ECM will conclude that the closed-loop fuel control is malfunctioning. The ECM will illuminate the
MIL and a DTC is set.
DIC28-01
Page 1179 of 3115
DI-130
- DIAGNOSTICSENGINE
323 Author: Date:
2004 LAND CRUISER (RM1071U)
MONITOR STRATEGY
RltdDTCP0134Excessive time to enter closed loop (Bank 1)Related DTCsP0154Excessive time to enter closed loop (Bank 2)
Main sensors/componentsFront heated oxygen sensor
Required sensors/componentsRelated sensors/componentsCrank position sensor, Engine coolant tempera-
ture sensor, Vehicle speed sensor
Frequency of operationOnce per drive cycle
Duration65 sec.
MIL operation1 driving cycle
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)
Both of the following conditions were metA and B
A. Time after following conditions met for
50 sec.(a), (b), (c), (d), (e) and (f)
(a) Engine coolant temperature40C (104°F)-
(b) Engine speed1,400 rpm-
(c) Vehicle speed40 km/h (25 mph)-
(d) IdleOFF
(e) Time after engine start180 sec.-
(f) Fuel enrichment correction factor163.998
B. Neither fail nor pass is determined yet in the present drive cycle
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Front heated oxygen sensor voltageLess than 0.45 V
COMPONENT OPERATING RANGE
ParameterStandard value
In the normal condition, the front heated oxygen sensor
voltage0 to 1 V
WIRING DIAGRAM
Refer to DTC P0031 on page DI-49.