2001 TOYOTA SEQUOIA check engine

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

A19552
Engine Coolant
Temp. Sensor
2
1THW
E2ECM
E2
B17441
Engine Coolant
Temp. Sensor
ECM
E2 THW
E2
THW
E2
E8ECM Connector
± DIAGNOSTICSENGINE
DI±123
317 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the E2 engine coolant temperature (ECT)
sensor connector.
(b) Connect terminals 1 and 2 of the engine coolant tempera-
ture sensor 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 /
COOLANT TEMP.
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 engine coolant temperature sensor.
NG
3 Check for open in harness or ECM.
PREPARATION:
(a) Disconnect the E2 engine coolant temperature sensor
connector.
(b) Connect terminals THW and E2 of the E8 ECM connector.
HINT:
Before checking, do a visual and contact pressure checks for
the ECM connector.
(c) Turn the ignition switch ON.
(d) 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 OBD II scan tool or the
hand±held tester.
OK:
Standard: Temperature value: 1405C (2845F) or more
OK Repair or replace harness or connector.
NG

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

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.

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±133
327 Author: Date:
2005 SEQUOIA (RM1146U)
1 Connect hand±held tester, and read the voltage for throttle position sensor data.
PREPARATION:
(a) Enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / THROTTLE POS
and THROTTLE POS #2.
CHECK:
Read voltage value displayed on the hand±held tester.
OK:
RESULT:
Throttle position expressed as percentage and voltage
Accelerator pedal releasedAccelerator pedal depressedTrouble areaProceed toTHROTTLE POS
(VTA1)THROTTLE POS #2
(VTA2)THROTTLE POS
(VTA1)THROTTLE POS #2
(VTA2)Trouble areaProceed to
0 %0 to 0.2 V0 %0 to 0.2 VVC circuit open
100 %4.5 to 5.5 V100 %4.5 to 5.5 VE2 circuit open
0 % or 100 %2.1 to 3.1 V
(Fail safe)0 % or 100 %2.1 to 3.1 V
(Fail safe)VTA1 circuit open or
ground shortA
about 16 %
(Fail safe)0 to 0.2 or 4.5 to 5.5 Vabout 16 %
(Fail safe)0 to 0.2 or 4.5 to 5.5 VVTA2 circuit open or
ground short
10 to 24 %2.15 to 3.05 V64 to 96 %
(Does not fail safe)4.5 to 5.5 V
(Does not fail safe)Throttle position sen-
sor circuit is normalB
B Go to step 5.
A

A21022
Throttle Control Motor and Sensor
VC VTA2VTA1
E2 Wire Harness Side
T14
Front View
B17412VC
E2
E8ECM Connector
VTA2
VTA1
DI±134
± DIAGNOSTICSENGINE
328 Author: Date:
2005 SEQUOIA (RM1146U)
2 Check for open and short in harness and connector between ECM and throttle
position sensor.
PREPARATION:
(a) Disconnect the T14 throttle control motor and sensor con-
nector.
(b) Disconnect the E8 ECM connector.
CHECK:
Check the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
VC (T14±5) ± VC (E8±18)Below 1 W
VTA1 (T14±6) ± VTA1 (E8±21)Below 1 W
VTA2 (T14±4) ± VTA2 (E8±31)Below 1 W
E2 (T14±3) ± E2 (E8±28)Below 1 W
VC (T14±5) or VC (E8±18) ±
Body ground10 kW or higher
VTA1 (T14±6) or VTA1 (E8±21) ±
Body ground10 kW or higher
VTA2 (T14±4) or VTA2 (E8±31) ±
Body ground10 kW or higher
NG Repair or replace harness or connector.
OK