Toyota Tundra. Manual — part 1347

e. Read the value displayed on the Techstream.

OK: The difference between the coolant temperature and the actual outside air temperature
is within 10°C (18°F).

HINT:

If the result is not as specified, check that there are heat sources such as a block heater in the engine
compartment.

NG : REPLACE ENGINE COOLANT TEMPERATURE SENSOR (See REMOVAL )

OK : REPLACE ECM (See REMOVAL )

DTC P0120 THROTTLE/PEDAL POSITION SENSOR/SWITCH "A" CIRCUIT MALFUNCTION;
DTC P0122 THROTTLE/PEDAL POSITION SENSOR/SWITCH "A" CIRCUIT LOW INPUT; DTC
P0123 THROTTLE/PEDAL POSITION SENSOR/SWITCH "A" CIRCUIT HIGH INPUT; DTC P0220
THROTTLE/PEDAL POSITION SENSOR/SWITCH "B" CIRCUIT; DTC P0222 THROTTLE/PEDAL
POSITION SENSOR/SWITCH "B" CIRCUIT LOW INPUT; DTC P0223 THROTTLE/PEDAL
POSITION SENSOR/SWITCH "B" CIRCUIT HIGH INPUT; DTC P2135 THROTTLE/PEDAL
POSITION SENSOR/SWITCH "A"/"B" VOLTAGE CORRELATION

DESCRIPTION

The TP sensor is mounted on the throttle body, and detects the opening angle of the throttle valve. This sensor is
a non-contact type. It uses Hall-effect elements in order to yield accurate signals even in extreme driving
conditions, such as at high speeds as well as very low speeds.

The TP sensor has 2 sensor circuits, each of which transmits a signal, VTA1 and VTA2. VTA1 is used to detect
the throttle valve angle and VTA2 is used to detect malfunctions in VTA1. The sensor signal voltages vary
between 0 V and 5 V in proportion to the throttle valve opening angle, and are transmitted to the VTA terminals
of the ECM.

As the valve closes, the sensor output voltage decreases and as the valve opens, the sensor output voltage
increases. The ECM calculates the throttle valve opening angle according to these signals and controls the
throttle actuator in response to driver inputs. These signals are also used in calculations such as air-fuel ratio
correction, power increase correction and fuel-cut control.

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

Fig. 76: Throttle / Pedal Position Sensor / Switch "A" Circuit Diagram

DTC DETECTION CONDITION AND TROUBLE AREA

DTC

Code

DTC Detection Condition

Trouble Area

P0120

Output voltage of VTA1 quickly fluctuates beyond lower and
upper malfunction thresholds for 2 seconds when accelerator
pedal depressed
(1 trip detection logic)



Throttle Position (TP)
sensor (built into throttle
body)



ECM

P0122

Output voltage of VTA1 0.2 V or less for 2 seconds when
accelerator pedal depressed
(1 trip detection logic)



TP sensor (built into
throttle body)



Short in VTA1 circuit



Open in VC circuit



ECM



TP sensor (built into
throttle body)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

HINT:



When any of these DTCs are set, check the throttle valve opening angle by entering the following menus:
Powertrain/Engine and ECT/Data List/ETCS/Throttle Position No. 1 and Throttle Position No. 2.



Throttle Position No. 1 is the VTA1 signal, and Throttle Position No. 2 is the VTA2 signal.

Reference (Normal Condition)

ACCELERATOR PEDAL POSITION

MONITOR DESCRIPTION

P0123

Output voltage of VTA1 4.535 V or higher for 2 seconds when
accelerator pedal depressed
(1 trip detection logic)



Open in VTA1 circuit



Open in E2 circuit



Short between VC and
VTA1 circuits



ECM

P0220

Output voltage of VTA2 quickly fluctuates beyond lower and
upper malfunction thresholds for 2 seconds when accelerator
pedal depressed
(1 trip detection logic)



TP sensor (built into
throttle body)



ECM

P0222

Output voltage of VTA2 1.75 V or less for 2 seconds when
accelerator pedal depressed
(1 trip detection logic)



TP sensor (built into
throttle body)



Short in VTA2 circuit



Open in VC circuit



ECM

P0223

Output voltage of VTA2 4.8 V or higher, and VTA1 between
0.2 V and 2.02 V for 2 seconds when accelerator pedal
depressed
(1 trip detection logic)



TP sensor (built into
throttle body)



Open in VTA2 circuit



Open in E2 circuit



Short between VC and
VTA2 circuits



ECM

P2135

Either condition (a) or (b) met (1 trip detection logic):

a. Difference between output voltages of VTA1 and VTA2

0.02 V or less for 0.5 seconds or more

b. Output voltage of VTA1 0.2 V or less, and VTA2 1.75 V

or less, for 0.4 seconds or more



Short between VTA1 and
VTA2 circuits



TP sensor (built into
throttle body)



ECM

Tester Display

Accelerator Pedal Fully Released

Accelerator Pedal Fully Depressed

Throttle Position No. 1

0.5 to 1.1 V

3.3 to 4.9 V

Throttle Position No. 2

2.1 to 3.1 V

4.6 to 5.0 V

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

The ECM uses the Throttle Position (TP) sensor to monitor the throttle valve opening angle. There are several
checks that the ECM performs to confirm the proper operation of the TP sensor.



A specific voltage difference is expected between the sensor terminals, VTA1 and VTA2, for each
throttle valve opening angle. If the difference between VTA1 and VTA2 is incorrect, the ECM interprets
this as a malfunction in the sensor, and sets a DTC.



VTA1 and VTA2 each have a specific voltage range. If VTA1 or VTA2 is outside the normal operating
range, the ECM interprets this as a malfunction in the sensor, and sets a DTC.



VTA1 and VTA2 should never be close to the same voltage level. If VTA1 is within 0.02 V of VTA2, the
ECM determines that there is a short circuit in the sensor, and sets a DTC.

If the malfunction is not repaired successfully, a DTC is set 10 seconds after the engine is next started.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

Related DTCs

P0120: Throttle position sensor 1 range check (Fluctuating)
P0122: Throttle position sensor 1 range check (Low voltage)
P0123: Throttle position sensor 1 range check (High voltage)
P0220: Throttle position sensor 2 range check (Fluctuating)
P0222: Throttle position sensor 2 range check (Low voltage)
P0223: Throttle position sensor 2 range check (High voltage)
P2135: Throttle position sensor range check (Correlation)

Required Sensors/Components
(Main)

Throttle position sensor

Required Sensors/Components
(Related)

-

Frequency of Operation

Continuous

Duration

2 seconds: P0120, P0122, P0123, P0220, P0222 and P0223
(Accelerator pedal ON)
10 seconds: P0120, P0122, P0123, P0220, P0222 and P0223
(Accelerator pedal OFF)
0.5 seconds: P2135 Case 1
0.4 seconds: P2135 Case 2

MIL Operation

Immediate

Sequence of Operation

None

Monitor runs whenever following DTCs not present

None

Either of following conditions A or B met

-

A. Ignition switch ON

0.012 seconds or more

B. Electronic throttle actuator power

ON

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra