TOYOTA HIGHLANDER 2001 Service Repair Manual

Y
B53781
A81699A85510
Wire Harness Side
T13
Throttle Position Sensor
VC VTA2VTA1
E2
VC
VTA1
VTA2 E2 E7
ECM
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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297 Author
: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
Hand-held tester:
1 READ VALUE OF HAND-HELD TESTER (THROTTLE POS AND THROTTLE POS
#2)
(a) On the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST
/ ALL / THROTTLE POS and THROTTLE POS #2. Read the values.
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 %2.1 to 3.1 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
2 CHECK WIRE HARNESS (THROTTLE POSITION SENSOR - ECM)
(a) Disconnect the T13 throttle position sensor connector.
(b) Disconnect the E7 ECM connector.
(c) Measure the resistance of the wire harness side connec-
tors.
Standard:
Tester ConnectionSpecified Condition
T13-5 (VC) - E7-18 (VC)
T13-6 (VTA1) - E7-21 (VTA1)
T13-4 (VTA2) - E7-31 (VTA2)
T13-3 (E2) - E7-28 (E2)
Below 1 W
T13-5 (VC) or E7-18 (VC) - Body ground
T13-6 (VTA1) or E7-21 (VTA1) - Body ground
T13-4 (VTA2) or E7-31 (VTA2) - Body ground
10 kW or higher
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR
OK

A76903
E2 (-)VC (+)
E7
ECM
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3 INSPECT ECM (VC VOLTAGE)
(a) Disconnect the T13 throttle position sensor connector.
(b) Turn the ignition switch ON.
(c) Measure the voltage of the ECM connector.
Standard:
Tester ConnectionSpecified Condition
E7-18 (VC) - E7-28 (E2)4.5 to 5.5 V
NG REPLACE ECM (See page 10-9)
OK
4 REPLACE THROTTLE BODY ASSY (See page 10-6)
GO
5 READ OUTPUT DTC (THROTTLE POSITION SENSOR DTCS ARE OUTPUT AGAIN)
(a) Clear the DTC (see page 05-38).
(b) Start the engine.
(c) Run the engine at idle for 15 seconds or more.
(d) Read the DTC.
Result:
Display (DTC Output)Proceed to
P0120, P0122, P0123, P0220, P0222, P0223 and/or P2135 are output againA
No DTC outputB
B SYSTEM OK
A
REPLACE ECM (See page 10-9)

Y
B53781
A81699A85510
Wire Harness Side
T13
Throttle Position Sensor
VC VTA2VTA1
E2
VC
VTA1
VTA2 E2 E7
ECM
A76903
VC (+)
E2 E7
ECM
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
OBD II scan tool (excluding hand-held tester):
1 CHECK WIRE HARNESS (THROTTLE POSITION SENSOR - ECM)
(a) Disconnect the T13 throttle position sensor connector.
(b) Disconnect the E7 ECM connector.
(c) Measure the resistance of the wire harness side connec-
tors.
Standard:
Tester ConnectionSpecified Condition
T13-5 (VC) - E7-18 (VC)
T13-6 (VTA1) - E7-21 (VTA1)
T13-4 (VTA2) - E7-31 (VTA2)
T13-3 (E2) - E7-28 (E2)
Below 1 W
T13-5 (VC) or E7-18 (VC) - Body ground
T13-6 (VTA1) or E7-21 (VTA1) - Body ground
T13-4 (VTA2) or E7-31 (VTA2) - Body ground
10 kW or higher
NG REPAIR OR REPLACE HARNESS AND
CONNECTOR
OK
2 INSPECT ECM (VC VOLTAGE)
(a) Disconnect the T13 throttle position sensor connector.
(b) Turn the ignition switch ON.
(c) Measure the voltage of the ECM connector.
Standard:
Tester ConnectionSpecified Condition
E7-18 (VC) - E7-28 (E2)4.5 to 5.5 V
NG REPLACE ECM (See page 10-9)
OK
3 REPLACE THROTTLE BODY ASSY (See page 10-6)
G0

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4 READ OUTPUT DTC (THROTTLE POSITION SENSOR DTCS ARE OUTPUT AGAIN)
(a) Clear the DTC (see page 05-38).
(b) Start the engine.
(c) Run the engine at idle for 15 seconds or more.
(d) Read the DTC.
Result:
Display (DTC Output)Proceed to
P0120, P0122, P0123, P0220, P0222, P0223 and/or P2135 are output againA
No DTC outputB
B SYSTEM OK
A
REPLACE ECM (See page 10-9)

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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
DTC P0121 THROTTLE/PEDAL POSITION
SENSOR/SWITCH ºAº CIRCUIT
RANGE/PERFORMANCE PROBLEM
HINT:
This is the purpose of the ºthrottle position sensorº.
CIRCUIT DESCRIPTION
Refer to DTC P0120 on page 05-102.
DTC No.DTC Detection ConditionTrouble Area
P0121
Condition (a) continues for 2.0 seconds:
(a) Difference between VTA1 and VTA2 deviates from thresh-
old
Throttle position sensor
MONITOR DESCRIPTION
The ECM uses the throttle position sensor to monitor the throttle valve opening angle.
This sensor includes 2 signals: VTA1 and VTA2. VTA1 is used to detect the throttle opening angle and VTA2
is used to detect malfunctions in VTA1. There are several checks that the ECM performs to confirm proper
operation of the throttle position sensor and VTA1.
There is a specific voltage difference between VTA1 and VTA2 for each throttle opening angle.
If the voltage output difference between the VTA1 and VTA2 deviates from the normal operating range, the
ECM interprets this as a malfunction of the throttle position sensor. The ECM will turn on the MIL and will
set a DTC.
FAIL-SAFE
If the Electronic Throttle Control System (ETCS) 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 injection (inter-
mittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the
vehicle to continue at a minimal 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
Related DTCsP0121: TP (Throttle position) sensor rationality
Required sensors / components (Main)TP sensor
Required sensors / components (Related)-
Frequency of operationContinuous
Duration2 sec.
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever this DTC is not presentSee page 05-16
052NE-53

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TYPICAL MALFUNCTION THRESHOLDS
Difference in learning voltage value of (VTA1 - VTA2 y0.8)Less than 0.8 V, or more than 1.6 V
INSPECTION PROCEDURE
HINT:
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 deter-
mine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean
or rich, and other data from the time the malfunction occurred.
REPLACE THROTTLE POSITION SENSOR (See page 10-6)

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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DTC P0125 INSUFFICIENT COOLANT TEMPERATURE
FOR CLOSED LOOP FUEL CONTROL
CIRCUIT DESCRIPTION
Refer to DTC P0115 on page 05-95.
DTC No.DTC Detection ConditionTrouble Area

If ECT (engine coolant temperature) or IAT (intake air temper-
ature) is less than -19.45°C (-3°F) at engine start; 20 min-
utes or more after starting engine, ECT sensor value is 20°C
(68°F) or less (2 tripdetection logic)
P0125
(68°F) or less (2 trip detection logic)

If ECT and IAT are between -19.45°C (-3°F) and -8.34°C
(17°F) at engine start; 5 minutes or more after starting en-
gine, ECT sensor value is 20°C (68°F) or less (2 trip detec-
ti l i )

Cooling system

ECT sensor

Thermostat
tion logic)

If ECT and IAT greater than -8.34°C (17°F) at engine start; 2
minutes or more after starting engine, ECT sensor value is
20°C (68°F) or less (2 trip detection logic)
MONITOR DESCRIPTION
The Engine Coolant Temperature (ECT) 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 warm enough for closed-loop fuel control, the ECM interprets this as a fault in the sensor or
cooling system and sets a DTC.
Example:
The ECT is 0C (32F) at engine start. After 5 minutes running time, the ECT sensor still indicates that the
engine is not warm enough to begin active feedback control of the air-fuel ratio. The ECM interprets this as
a fault in the sensor or cooling system and sets a DTC.
MONITOR STRATEGY
Related DTCsP0125: Insufficient ECT (Engine coolant temperature) for closed loop
Required sensors/components (Main)Thermostat, cooling sysem
Required sensors/components (Related)ECT sensor, MAF meter
Frequency of operationContinuous
Duration
2 minutes: Engine start ECT is -8.34C (17F) or more
5 minutes: Engine start ECT is -19.45 to -8.34C (-3 to 17F)
20 minutes: Engine start ECT is less than -19.45C (-3F)
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever the following DTCs are not
presentSee page 05-16
Fuel cutOFF
EngineRunning
IdleOFF
TYPICAL MALFUNCTION THRESHOLDS
Time until ºactual ECTº reaches ºClosed Loop ECTº
2 minutes: Engine start ECT is -8.34C (17F) or more
5 minutes: Engine start ECT is -19.45 to -8.34C (-3 to 17F)
20 minutes: Engine start ECT is less than -19.45C (-3F)
05ESW-05

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INSPECTION PROCEDURE
HINT:

If DTCs 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, and other data from the time the malfunction occurred.
1 CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0125)
(a) Read the DTC using the hand-held tester or the OBD II scan tool.
Result:
Display (DTC Output)Proceed to
Only P0125 are outputA
P0125 and other DTCs are outputB
HINT:
If any other codes besides P0125 is output, perform the troubleshooting for those codes first.
B GO TO RELEVANT DTC CHART
(See page 05-48)
A
2 INSPECT THERMOSTAT (See page 16-2)
(a) Check the valve opening temperature of the thermostat.
OK:
Valve opening temperature: 80 to 84C (176 to 183F)
HINT:
Also check that the valve is completely closed under opening temperature as above.
NG REPLACE THERMOSTAT (See page 16-1 1)
OK
3 CHECK COOLING SYSTEM
(a) Check the cooling system for excessive cooling, such as abnormal radiator fan operation, modified
cooling system and other defects.
OK:
There is no modification of cooling system.
NG REPAIR OR REPLACE COOLING SYSTEM
OK
REPLACE ENGINE COOLANT TEMPERATURE SENSOR

A82385
ECTEstimated ECT
Threshold
(75C (167F))5 seconds
Indicated coolant temperature reading
Time
DTC set (after 2 driving cycles)
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DTC P0128 COOLANT THERMOSTAT (COOLANT
TEMPERATURE BELOW THERMOSTAT
REGULATING TEMPERATURE)
CIRCUIT DESCRIPTION
This DTC is output when the Engine Coolant Temperature (ECT) does not reach 75°C (167°F) despite suffi-
cient engine warm-up time.
DTC No.DTC Detection ConditionTrouble Area
P0128
Conditions (a), (b) and (c) are met:
(a) Cold start
(b) Sufficient warm-up time has elapsed
(c) ECT is less than 75°C (167°F)
Thermostat

Cooling system

ECT 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. When the estimated cool-
ant 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 the engine cooling system and set a DTC.
05ETK-05

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MONITOR STRATEGY
Related DTCsP0128: Coolant thermostat
Required sensors/components (Main)Thermostat
Required sensors/components (Related)ECT sensor, IAT sensor, VSS
Frequency of operationOnce per driving cycle
Duration500 sec.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever this DTC is not presentSee page 05-16
Battery voltage11 V or more
Throttle position learningCompleted
Either of the following conditions is met:Condition 1 or 2
1. All of the following conditions are met:Condition (a), (b) and (c)
(a) ECT at engine start - IAT at engine start-15 to 7C (-27 to 12.6F)
(b) ECT at engine start-10 to 56C (14 to 132.8F)
(c) IAT at engine start-10 to 56C (14 to 132.8F)
2. All of the following conditions are met:Condition (a), (b) and (c)
(a) ECT at engine start - IAT at engine startMore than 7C (12.6F)
(b) ECT at engine start56C (132.8F) or less
(c) IAT at engine start-10C (14F) or more
Accumulated time that vehicle speed is 80 mph (128 km/h)
or moreLess than 20 seconds
TYPICAL MALFUNCTION THRESHOLDS
Duration that both of the following conditions 1 and 2 are
met:5 seconds or more
1. Estimated ECT120.5C (248.9F) or more
2. ECT sensor outputLess than 120.5C (248.9F)
MONITOR RESULT
Refer to page 05-24 for detailed information.
The test value and test limit information are described as shown in the following table. Check the monitor
result and test values after performing the monitor drive pattern (see page 05-26).

TID (Test Identification Data) is assigned to each emissions-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 Data) is assigned to each test value.

Unit Conversion is used to calculate the test value indicated on generic OBD ll scan tools.
TID $08: Thermostat
TLTCIDUnit ConversionDescription of Test DataDescription of Test Limit
1$01
Multiply by 0.625 and subtract
40
(C)ECT sensor output when estimated ECT
has reached to malfunction criterionMalfunction criteria for thermostat