2001 TOYOTA SEQUOIA Page 18

DI±114
± DIAGNOSTICSENGINE
308 Author: Date:
2005 SEQUOIA (RM1146U)
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 is 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 these
DTCs are not presentSee page DI±18
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))

DI±116
± DIAGNOSTICSENGINE
310 Author: Date:
2005 SEQUOIA (RM1146U)
1 Connect hand±held tester, and read value of intake air temperature.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main switch ON.
(c) When using hand±held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / ALL / INTAKE AIR.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Same as actual intake air temperature.
RESULT:
Displayed TemperatureProceed 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 hand±held tester indicates ±40°C (±40°F).

If there is a short circuit, the hand±held tester indicates 140°C (284°F) or more.
B Go to step 4.
C Check for intermittent problems
(See page DI±11).
A

A19549
THA
E2ECM
2
1
Mass Air
Flow Meter Mass Air
Flow Meter
45
M1
THA E2
M1
B17441THA
E2
THA
E2ECM Mass Air Flow Meter
M1
E8
± DIAGNOSTICSENGINE
DI±117
311 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the M1 mass air flow meter connector.
(b) Connect terminals 4 and 5 of the mass air flow meter wire
harness side connector.
(c) Turn the ignition switch ON.
(d) When using hand±held tester, enter the following menu:
DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / IN-
TAKE AIR.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Standard: Temperature value: 1405C (2845F) or more
OK Confirm good connection at sensor. If OK, re-
place mass air flow meter.
NG
3 Check for open in harness or ECM.
PREPARATION:
(a) Connect terminals THA and E2 of the E8 ECM connector.
HINT:
Before checking, do a visual and contact pressure check for the
ECM connector.
(b) Turn the ignition switch ON.
(c) When using hand±held tester, enter the following menu:
DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / IN-
TAKE AIR.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Standard: Temperature value: 1405C (2845F) or more
OK Repair or replace harness or connector.
NG
Confirm good connection at ECM. If OK, re-
place ECM (See page SF±80).

A19550
THA
E2ECM Mass Air Flow
Meter
M1
B17442
ECM Mass Air Flow Meter
THA
E2 M1
E8
DI±118
± DIAGNOSTICSENGINE
312 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the M1 mass air flow meter connector.
(b) Turn the ignition switch ON.
(c) When using hand±held tester, enter the following menu:
DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / IN-
TAKE AIR.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Standard: Temperature value: ±405C (±405F)
OK Replace mass air flow meter.
NG
5 Check for short in harness or ECM.
PREPARATION:
(a) Disconnect the E8 ECM connector.
(b) Turn the ignition switch ON.
(c) When using hand±held tester, enter the following menu:
DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / IN-
TAKE AIR.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Standard: Temperature value: ±405C (±405F)
OK Repair or replace harness or connector.
NG
Replace ECM (See page SF±80).

DI±120
± DIAGNOSTICSENGINE
314 Author: Date:
2005 SEQUOIA (RM1146U)
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.
MONITOR STRATEGY
P0115Engine coolant temperature sensor range check
(Fluttering)
Related DTCsP0117Engine coolant temperature sensor range check
(Low resistance)
P0118Engine coolant temperature sensor range check
(High resistance)
Required sensors/componentsEngine coolant temperature sensor
Frequency of operationContinuous
Duration0.5 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever these
DTCs are not presentSee page DI±18
The typical enabling condition is not avail-
able±
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P0115:
Engine coolant temperature sensor resistance
(Coolant temperature)Less than 79 W, or more than 156 kW
(More than 140C (284F), or less than ±40C (±40F))
P0117:
Engine coolant temperature sensor resistance
(Coolant temperature)Less than 79 W
(More than 140C (284F))
P0118:
Engine coolant temperature sensor resistance
(Coolant temperature)More than 156 kW
(Less than ±40C (±40F))
COMPONENT OPERATING RANGE
ParameterStandard Value
Engine coolant temperature sensor resistance79 W (140C (284F)) to 156 kW (±40C (±40F))

DI±122
± DIAGNOSTICSENGINE
316 Author: Date:
2005 SEQUOIA (RM1146U)
1 Connect hand±held tester, and read value of engine coolant temperature.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main switch ON.
(c) When using hand±held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / ALL / COOLANT TEMP.
CHECK:
Read the temperature value on the the hand±held tester.
OK:
Same value as actual engine coolant temperature.
RESULT:
Displayed TemperatureProceed 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, hand±held tester indicates ±40°C (±40°F).

If there is a short circuit, hand±held tester indicates 140°C (284°F) or more.
B Go to step 4.
C Check for intermittent problems
(See page DI±11).
A

A19550
Engine Coolant
Temp. Sensor
ECM
2
1
E2 THW E2
B17442
ECM Engine Coolant
Temp. Sensor
E2 THW E2
ECM Connector E8
DI±124
± DIAGNOSTICSENGINE
318 Author: Date:
2005 SEQUOIA (RM1146U)
Confirm good connection at ECM. If OK, re-
place ECM (See page SF±80).
4 Check for short in harness and ECM.
PREPARATION:
(a) Disconnect the E2 engine coolant temperature sensor
connector.
(b) Turn the ignition switch ON.
(c) When using hand±held tester, enter the following menu:
DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL /
COOLANT TEMP.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Standard: Temperature value: ±405C (±405F)
OK Replace engine coolant temperature sensor.
NG
5 Check for short in harness or ECM.
PREPARATION:
(a) Disconnect the E8 ECM connector.
(b) Turn the ignition switch ON.
(c) When using hand±held tester, enter the following menu:
DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL /
COOLANT TEMP.
CHECK:
Read the temperature value on the hand±held tester.
OK:
Standard: Temperature value: ±405C (±405F)
OK Repair or replace harness or connector.
NG
Replace ECM (See page SF±80).

± DIAGNOSTICSENGINE
DI±125
319 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0116 Engine Coolant Temperature Circuit Range/
Performance Problem
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page DI-119.
DTC No.DTC Detecting ConditionTrouble Area
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)
P0116If the engine coolant temperature is more 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) If the engine coolant temperature sensor records a temper-
ature 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
DI3HP±11