Toyota Tundra. Manual — part 1603

HINT

When any of these DTCs are stored, check the APP sensor voltage by entering the following menus
Powertrain/Engine and ECT/Data List/ETCS/Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

APP SENSOR VOLTAGE REFERENCE

HINT

P2125

upper and lower malfunction
thresholds for 0.5 seconds or more
(1 trip detection logic)



ECM

P2127

VPA2 1.2 V or less for 0.5 seconds
or more when accelerator pedal
fully released (1 trip detection
logic)



APP sensor



Open in VCP2 circuit



Open or ground short in
VPA2 circuit



ECM

P2128

Conditions (a) and (b) continue for
2.0 seconds or more (1 trip
detection logic)

a. VPA2 4.8 V or more

b. VPA between 0.4 V and 3.45

V



APP sensor



Open in EPA2 circuit



ECM

P2138

Condition (a) or (b) continues for
2.0 seconds or more (1 trip
detection logic)

a. Difference between VPA

and VPA2 0.02 V or less

b. VPA 0.4 V or less and VPA2

1.2 V or less



Short between VPA and
VPA2 circuits



APP sensor



ECM

Trouble Area

Accel Sensor Out

No. 1 When AP

Released

Accel Sensor Out

No. 2 When AP

Released

Accel Sensor Out

No. 1 When AP

Depressed

Accel Sensor Out

No. 2 When AP

Depressed

VCP circuit open

0 to 0.2 V

0 to 0.2 V

0 to 0.2 V

0 to 0.2 V

Open or ground

short in VPA

circuit

0 to 0.2 V

1.2 to 2.0 V

0 to 0.2 V

3.4 to 4.7 V

Open or ground

short in VPA2

circuit

0.5 to 1.1 V

0 to 0.2 V

2.6 to 4.5 V

0 to 0.2 V

EPA circuit open

4.5 to 5.0 V

4.5 to 5.0 V

4.5 to 5.0 V

4.5 to 5.0 V

Normal condition

0.5 to 1.1 V

1.2 to 2.0 V

2.6 to 4.5 V

3.4 to 4.7 V

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra



Accelerator pedal positions are expressed as voltages.



AP stands for Accelerator Pedal.

MONITOR DESCRIPTION

When either output voltage of VPA or VPA2 deviates from the standard range, or the difference between the
output voltages of the 2 sensor circuits is less than the threshold, the ECM determines that there is a malfunction
in the APP sensor. The ECM then illuminates the MIL and stores a DTC.

Example

When the output voltage of VPA drops below 0.4 V for more than 0.5 seconds when the accelerator pedal is
fully depressed, DTC P2122 is stored.

If the malfunction is not repaired successfully, a DTC is stored 2 seconds after the engine is next started.

MONITOR STRATEGY

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

P2120:

Related DTCs

P2120 APP sensor 1 range check (fluctuating)
P2122 APP sensor 1 range check (low voltage)
P2123 APP sensor 1 range check (high voltage)
P2125 APP sensor 2 range check (fluctuating)
P2127 APP sensor 2 range check (low voltage)
P2128 APP sensor 2 range check (high voltage)
P2138 APP sensor range check (con-elation)

Required Sensors/Components (Main)

APP sensor

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.5 seconds P2120, P2122, P2125 and P2127
2.0 seconds P2123, P2128 and P2138

MIL Operation

Immediate

Sequence of Operation

None

Monitor runs whenever following DTCs not present

None

Either of following conditions 1 or 2 met

-

1. Ignition switch

ON

2. Throttle actuator power

ON

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS - P2120

P2122:

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS - P2122

P2123:

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS - P2123

P2125:

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS - P2125

P2127:

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS - P2127

P2128:

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS - P2128

P2138:

TYPICAL MALFUNCTION THRESHOLDS CONDITIONS - P2138

COMPONENT OPERATING RANGE

Either of following conditions 1 or 2 met
1. VPA voltage when VPA2 voltage 0.04 V or more

0.4 V or less

2. VPA voltage

4.8 V or more

VPA voltage when VPA2 voltage 0.04 V or more

0.4 V or less

VPA voltage

4.8 V or more

Either of following conditions 1 or 2 met
1. VPA2 voltage when VPA voltage 0.04 V or more

1.2 V or less

2. VPA2 voltage when VPA voltage 0.4 to 3.45 V

4.8 V or more

VPA2 voltage when VPA voltage 0.04 V or more

1.2 V or less

VPA2 voltage when VPA voltage 0.4 to 3.45 V

4.8 V or more

Either of following conditions A or B met

-

Condition A

-

Difference between VPA and VPA 2 voltages

0.02 V or less

Condition B

-

VPA voltage

0.4 V or less

VPA2 voltage

1.2 V or less

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra

COMPONENT OPERATING RANGE

FAIL-SAFE

When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are stored, the ECM enters
fail-safe mode. If either of the 2 sensor circuits malfunctions, the ECM uses the remaining circuit to calculate
the accelerator pedal position to allow the vehicle to continue driving. If both of the circuits malfunction, the
ECM regards the accelerator pedal as being released. As a result, the throttle valve is closed and the engine
idles.

Fail-safe mode continues until a pass condition is detected, and the ignition switch is turned off.

WIRING DIAGRAM

Fig. 229: Acclerator Pedal Position Sensor - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

HINT



These DTCs relate to the Accelerator Pedal Position (APP) sensor.



Read freeze frame data using the Techstream. Freeze frame data records the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was
moving or stationary, 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. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION SENSOR)

a. Connect the Techstream to the DLC3.

b. Turn the ignition switch to ON and turn the Techstream ON.

c. Enter the following menus Powertrain/Engine and ECT/Data List/ETCS/Accel Sensor Out No. 1

and Accel Sensor Out No. 2.

d. Read the value displayed on the Techstream.

VPA voltage

0.5 to 4.7 V

VPA2 voltage

1.2 to 4.7 V

Difference between VPA and VPA2 voltages

More than 0.02 V

2009 Toyota Tundra

2009 ENGINE PERFORMANCE Engine Control System (3UR-FBE) - Tundra