o2 sensor TOYOTA HIGHLANDER 2001 Service Repair Manual

05-104
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
294 Author
: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)DTC No.
DTC Detection Condition
Condition (a) of DTC P0120, P0122, P0123, P0220, P0222 or P0223 continues
for 2 seconds
(open or short in the throttle position sensor circuit)Trouble Area
P0120
Detection conditions for DTCs P0122 and P0123 are not satis-
fied but condition (a) is satisfied
(a) VTA1 is 0.2 V or less or VTA1 is 4.8 V or more
Throttle position sensor

ECM
P0122(a) VTA1 is 0.2 V or less

Throttle position sensor

Short in VTA1 circuit

Open in VC circuit

ECM
P0123(a) VTA1 is 4.8 V or more

Throttle position sensor

Open in VTA1 circuit

Open in E2 circuit

Short in VC and VTA1 circuits

ECM
P0220
Detection conditions for DTCs P0222 and P0223 are not satis-
fied but condition (a) is satisfied
(a) VTA2 is 0.5 V or less or VTA2 is 4.8 V or more and
VTA1 is 0.2 V or more and VTA1 is 1.8 V or less

Throttle position sensor

ECM
P0222(a) VTA2 is 0.5 V or less

Throttle position sensor

Short in VTA2 circuit

Open in VC circuit

ECM
P0223(a) VTA2 is 4.8 V or more and
VTA1 is 0.2 V or more and VTA1 is 1.8 V or less

Throttle position sensor

Open in VTA2 circuit

Open in E2 circuit

Short in VC and VTA2 circuits

ECM
P2135
Condition (a) continues for 0.5 seconds or more, or
condition (b) continues for 0.4 seconds or more:
(a) Difference between VTA1 and VTA2 is 0.02 V or less
(b) VTA1 is 0.2 V or less and VTA2 is 0.5 V or less
Short in VTA1 and VTA2 circuits

Throttle position 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.

ºTHROTTLE POSº is the VTA1 signal. ºTHROTTLE POS #2º is the VTA2 signal.
Reference (Normal condition):
Tester displayAccelerator pedal releasedAccelerator pedal fully depressed
THROTTLE POS10 to 24 %64 to 96 %
THROTTLE POS #22.1 to 3.1 V4.5 to 5.5 V

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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295 Author
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
MONITOR DESCRIPTION
The ECM uses the throttle position sensor to monitor the throttle valve opening angle.
(a) There is a specific voltage difference between VTA1 and VTA2 for each throttle opening angle.

If the difference between VTA1 and VTA2 deviates from the specified range, the ECM interprets this
as a fault and will set a DTC.
(b) VTA1 and VTA2 have each 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 the difference between VTA1 and VTA2 is within 0.02 V, the ECM interprets this as a short circuit
in the throttle position sensor system 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 DTCs
P0120: TP sensor 1 range check (Chattering)
P0122: TP sensor 1 range check (Low voltage)
P0123: TP sensor 1 range check (High voltage)
P0220: TP sensor 2 range check (Chattering)
P0222: TP sensor 2 range check (Low voltage)
P0223: TP sensor 2 range check (High voltage)
P2135: TP sensor range check (Correlation)
Required sensors/components (Main)TP (Throttle position) sensor
Required sensors/components (Related)-
Frequency of operationContinuous
Duration
Accelerator pedal ON: 2 seconds
Accelerator pedal OFF: 10 seconds
0.5 seconds or 0.4 seconds (P2135)
MIL operationImmediate
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
The monitor will run whenever these DTCs are not presentSee page 05-16
TYPICAL MALFUNCTION THRESHOLDS
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:

A90295
T13
Throttle Position Sensor ECM
5
VTA1
E2 VTA2VC
VTA1
E2 VTA2VC5 V
E7
4
3E7
E7
E7 2831 21 18
Y
B-R
BR 6B-W
BRBR
S28 S295
5 Short
Connector 05-106
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
296 Author
: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U) VTA2 voltage
0.5 V or less
P0223:
VTA2 voltage when the VTA1 is 0.2 to 1.8 V4.8 V or more
P2135:
Either of the following condition(s) is met:Condition A or B
Condition A-
Difference between VTA1 and VTA2 voltages0.02 V or less
Condition B-
VTA1 voltage0.2 V or less
VTA2 voltage0.5 V or less
COMPONENT OPERATING RANGE
VTA1 voltage0.6 to 3.96 V
VTA2 voltage2.25 to 4.8 V
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:

If DTCs that are related to different systems are output simultaneously while terminal E2 is used as
a ground terminal, terminal E2 may have an open circuit.

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.

Y
B53781
A81699A85510
Wire Harness Side
T13
Throttle Position Sensor
VC VTA2VTA1
E2
VC
VTA1
VTA2 E2 E7
ECM
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-107
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
05-108
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
298 Author
: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
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
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
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: Date
:
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

05-1 10
- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
300 Author
: Date
:
2005 HIGHLANDER REPAIR MANUAL (RM1144U)
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)

- DIAGNOSTICSSFI SYSTEM (2AZ-FE)
05-1 11
301 Author
: Date
:
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

05-1 12
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: Date
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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
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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2005 HIGHLANDER REPAIR MANUAL (RM1144U)
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