2001 TOYOTA SEQUOIA engine

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

DI±126
± DIAGNOSTICSENGINE
320 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
Case 1 (When temperature is fixed between 35C (95F) and 60C (140F)):
Cumulative idle off period250 sec.±
Speed increase 30 km/h (18.6 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 (43.5 mph)
with in 40 sec.)
Steady driving and stop *Once or more
*: Vehicle is driven by 65 km/h (40.4 mph) or more for 30 sec. or more and the vehicle speed reaches 70
km/h (43.5 mph). The vehicle is decelerated from 65 km/h (40.4 mph) to 3 km/h (1.86 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. 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±127
321 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0120 Throttle/Pedal Position Sensor/Switch ºAº
Circuit
DTC P0122 Throttle/Pedal Position Sensor/Switch ºAº
Circuit Low Input
DTC P0123 Throttle/Pedal Position Sensor/Switch ºAº
Circuit High Input
DTC P0220 Throttle/Pedal Position Sensor/Switch ºBº
Circuit
DTC P0222 Throttle/Pedal Position Sensor/Switch ºBº
Circuit Low Input
DTC P0223 Throttle/Pedal Position Sensor/Switch ºBº
Circuit High Input
DTC P2135 Throttle/Pedal Position Sensor/Switch
ºAº/ºBº Voltage Correction
HINT:
This is the purpose for the ºthrottle position sensorº.
DID84±01

A19755A21037
Throttle Position Sensor ECM
Magnet
Magnet
IC No.2 IC No.1
VC
VTA1
E2 VTA2Throttle Position Sensor Output Voltage (V)
Fail Safe Angle
*1
Usable Range
Throttle Valve Opening Angle (deg)84 6
0 5
2.60
2.25
0.97
0.69
Throttle Valve Fully Opened
(Throttle Position expressed as percentage
(VTA1) 64 to 96%)
Fail Safe Angle 7°
(Throttle Position expressed as percentage
(VTA1) about 10 to 24%) Throttle Valve Fully Closed
(Throttle Position expressed as percentage
(VTA1) 10 to 20%)
*1:
VTA1 VTA2 DI±128
± DIAGNOSTICSENGINE
322 Author: Date:
2005 SEQUOIA (RM1146U)
CIRCUIT DESCRIPTION
HINT:

This Electrical Throttle Control System (ETCS) does not use a throttle cable.

This throttle position sensor is a non±contact type.
The throttle position sensor is mounted on the throttle body. It detects the opening angle of the throttle valve.
This sensor is electronically controlled and uses Hall±effect elements, so that accurate control and reliability
can be obtained. The throttle position sensor has 2 sensor elements / signal outputs: VTA1 and VTA2. VTA1
used to detect the throttle opening angle and VTA2 is used to detect malfunctions in VTA1. Voltage applied
to VTA1 and VTA2 change between 0 V and 5 V in proportion to the opening angle of the throttle valve. There
are several checks that the ECM performs to confirm proper operation of the throttle position sensor and
VTA1.
The ECM judges the current opening angle of the throttle valve from these signals input from terminals VTA1
and VTA2, and the ECM controls the throttle motor to make the throttle valve angle properly in response to
driver inputs.

± DIAGNOSTICSENGINE
DI±129
323 Author: Date:
2005 SEQUOIA (RM1146U)DTC No.
DTC Detection Condition
Condition (a) of DTC P0120, P0122, P0123, P0220, P0222 or P0223 continues
for 2 sec.
(Open or short in the throttle control motor and sensor circuit)Trouble Area
P0120
Detection conditions for DTCs P0122 and P0123 are not satis-
fied but condition (a) is satisfied
(a) VTA1 is º0.2 V or lessº or VTA1 is º4.8 V or moreº
Open or short in throttle control motor and sensor circuit

Throttle control motor and sensor

ECM
P0122(a) VTA1 is 0.2 V or less

Short in throttle control motor and sensor circuit

Throttle control motor and sensor

Short in VTA1 circuit

Open in VC circuit

ECM
P0123(a) VTA1 is 4.8 V or more

Open in throttle control motor and sensor circuit

Throttle control motor and sensor

Open in VTA1 circuit

Open in E2 circuit

VC and VTA1 circuit are short±circuited

ECM
P0220
Detection conditions for DTCs P0222 and P0223 are not satis-
fied but condition (a) is satisfied
(a) VTA2 is º0.5 V or lessº or VTA2 is º4.8 V or moreº
Throttle control motor and sensor

ECM
P0222(a) VTA2 is 0.5 V or less

Throttle control motor and sensor

Short in VTA2 circuit

Open in VC circuit

ECM
P0223(a) VTA2 is º4.8 V or moreº and
VTA1 is º0.2 V or moreº and VTA1 is º1.8 V or lessº

Throttle control motor and sensor

Open in VTA2 circuit

Open in E2 circuit

VC and VTA2 circuit are short±circuited

ECM
P2135
Condition (a) continues for 0.5 sec. or more, or
condition (b) continues for 0.4 sec. or more:
(a) Difference between VTA1 and VTA2 is 0.02 V or less
(b) VTA1 is º0.2 V or lessº and VTA2 is º0.5 V or lessº
VTA1 and VTA2 circuit are short±circuited

Throttle control motor and sensor

ECM
HINT:

After confirming DTCs, use the hand±held tester or the OBD II scan tool to confirm the throttle valve
opening percentage and closed throttle position switch condition.

THROTTLE POS means the VTA1 signal and the THROTTLE POS #2 means the VTA2 signal.
Reference (Normal condition):
Tester displayAccelerator pedal fully releasedAccelerator pedal fully depressed
THROTTLE POS10 to 24%66 to 98%
THROTTLE POS #22.1 to 3.1 V4.5 to 5.5 V

DI±130
± DIAGNOSTICSENGINE
324 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR DESCRIPTION
The ECM uses throttle position sensor to monitor the throttle valve opening angle.
(a) There is an expected specific voltage difference between VTA1 and VTA2 for each throttle opening
angle.

If the difference between VTA1 and VTA2 is incorrect the ECM interprets this as a fault and will set a
DTC.
(b) VTA1 and VTA2 each have a specific voltage operating range.

If VTA1 or VTA2 is out of the normal operating range the ECM interprets this as a fault and will set a
DTC.
(c) VTA1 and VTA2 should never be close to the same voltage levels.

If VTA1 is within the range of ± 0.02 V of VTA2 the ECM interprets this as a short circuit in the throttle
position sensor system and will set a DTC.
FAIL SAFE
If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle
control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by
the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (inter-
mittent fuel±cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the
vehicle to continue at a minimum speed.
If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.
If a ºpassº condition is detected and then the ignition switch is turned OFF, the fail±safe operation will stop
and the system will return to normal condition.
MONITOR STRATEGY
P0120Throttle position sensor (sensor 1) range check
(Fluttering)
P0122Throttle position sensor (sensor 1) range check
(Low voltage)
P0123Throttle position sensor (sensor 1) range check
(High voltage)
Related DTCsP0220Throttle position sensor (sensor 2) range check
(Fluttering)
P0222Throttle position sensor (sensor 2) range check
(Low voltage)
P0223Throttle position sensor (sensor 2) range check
(High voltage)
P2135Throttle position sensor range check (Correla-
tion)
Required sensors/componentsThrottle position sensor
Frequency of operationContinuous
Duration
Accelerator pedal ON: 2 sec.
Accelerator pedal OFF: 10 sec.
P2135: 0.5 sec. or 0.4 sec.
MIL operationImmediate
Sequence of operationNone

± DIAGNOSTICSENGINE
DI±131
325 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
The monitor will run whenever these
DTCs are not presentSee page DI±18
Throttle control motor powerON
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
P0120:
VTA1 voltage0.2 V or less, or 4.8 V or more
P0122:
VTA1 voltage0.2 V or less
P0123:
VTA1 voltage4.8 V or more
P0220:
VTA2 voltage0.5 V or less, or 4.8 V or more
P0222:
VTA2 voltage0.5 V or less
P0223:
Both of the following conditions are met for 2 sec. or more:Condition 1 and 2
1. VTA1 voltage0.2 to 1.8 V
2. VTA2 voltage4.8 V or more
P2135:
Different between VTA1 and VTA2 voltage0.02 V or less
Both of the following conditions are met:Condition 1 and 2
1. VTA1 voltage0.2 V or less
2. VTA2 voltage0.5 V or less
COMPONENT OPERATING RANGE
ParameterStandard Value
Throttle position sensor VTA1 voltage0.6 to 3.96 V
Throttle position sensor VTA2 voltage2.25 to 5.0 V