Toyota Tundra. Manual — part 1414

HINT:

When any of these DTCs are set, check the APP sensor voltage by entering the following menus:

Powertrain/Engine and ECT/Data List/ETCS/Accelerator Position No. 1 and Accelerator Position No. 2.

ACCELERATOR PEDAL POSITION

Code

P2120

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



APP sensor



ECM

P2122

VPA 0.4 V or less for 0.5 seconds or more when accelerator pedal
fully released (1 trip detection logic)



APP sensor



Open in VCP1 circuit



Open or ground short
in VPA circuit



ECM

P2123

VPA 4.8 V or higher for 2.0 seconds or more (1 trip detection
logic)



APP sensor



Open in EPA circuit



ECM

P2125

VPA2 fluctuates rapidly beyond upper and lower malfunction
thresholds for 0.5 seconds or more (1 trip detection logic)



APP sensor



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 higher

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

Accelerator

Position No. 1

When AP Released

Accelerator

Position No. 2

When AP Released

Accelerator Position

No. 1 When AP

Depressed

Accelerator Position

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

2008 Toyota Tundra

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

HINT:



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 sets 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 set.

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

MONITOR STRATEGY

MONITOR STRATEGY

Open or ground

short in VPA

circuit

0 to 0.2V

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 1.1V

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

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 (correlation)

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

2008 Toyota Tundra

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

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

P2120:

TYPICAL MALFUNCTION THRESHOLDS - P2120

P2122:

TYPICAL MALFUNCTION THRESHOLDS - P2122

P2123:

TYPICAL MALFUNCTION THRESHOLDS - P2123

P2125:

TYPICAL MALFUNCTION THRESHOLDS - P2125

P2127:

TYPICAL MALFUNCTION THRESHOLDS - P2127

P2128:

TYPICAL MALFUNCTION THRESHOLDS - P2128

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

Either of following conditions 1 or 2 met:

-

1. VPA voltage when VPA2 voltage 0.04 V or higher

0.4 V or less

2. VPA voltage

4.8 V or higher

VPA voltage when VPA2 voltage 0.04 V or higher

0.4 V or less

VPA voltage

4.8 V or higher

Either of following conditions 1 or 2 met:

-

1. VPA2 voltage when VPA voltage 0.04 V or higher

1.2 V or less

2. VPA2 voltage when VPA voltage 0.4 to 3.45 V

4.8 V or higher

VPA2 voltage when VPA voltage 0.04 V or higher

1.2 V or less

VPA2 voltage when VPA voltage 0.4 to 3.45 V

4.8 V or higher

2008 Toyota Tundra

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

P2138:

TYPICAL MALFUNCTION THRESHOLDS - P2138

COMPONENT OPERATING RANGE

COMPONENT OPERATING RANGE

FAIL-SAFE

When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are set, 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. 212: Throttle / Pedal Position Sensor - Wiring Diagram

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

VPA voltage

0.5 to 4.7 V

VPA2 voltage

1.2 to 4.7 V

Difference between VPA and VPA2 voltages

Higher than 0.02 V

2008 Toyota Tundra

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