Toyota Tundra. Manual — part 1238

OK : Go to next step.

3. CHECK ECM (VCPA AND VCP2 VOLTAGE)

a. Disconnect the A14 APP sensor connector.

b. Measure the voltage according to the value (s) in the table below.

Standard voltage

TESTER CONNECTION SPECIFIED CONDITION

NG : REPLACE ECM (See REMOVAL )

Fig. 199: Identifying A14 APP Sensor Connector Terminals

OK : Go to next step.

4. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

a. Replace the accelerator pedal rod assembly (See REMOVAL ).

5. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR

DTCS)

a. Connect the Techstream to the DLC3.

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

c. Clear DTCs (See DTC CHECK/CLEAR ).

d. Start the engine.

e. Allow the engine to idle for 15 seconds.

f. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.

Tester Connection

Switch Condition Specified Condition

A14-4 (VCPA) - A14-5 (EPA) Ignition switch ON

4.5 to 5.5 V

A14-1 (VCP2) - A14-2 (EPA2) Ignition switch ON

4.5 to 5.5 V

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

g. Read DTCs.

Result

RESULT CHART

B : SYSTEM OK

A : REPLACE ECM (See REMOVAL )

DTC P2121 THROTTLE/PEDAL POSITION SENSOR/SWITCH "D" CIRCUIT
RANGE/PERFORMANCE

DESCRIPTION

Refer to DTC P2120 .

DTC TROUBLE DETECTION CONDITION CHART

MONITOR DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal
position sensor has 2 sensor elements and 2 signal outputs: VPA and VPA2. VPA is used to detect the actual
accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA. When the
difference between the output voltages of VPA and VPA2 deviates from the standard, the ECM determines that
the accelerator pedal position sensor is malfunctioning. The ECM turns on the MIL and the DTC is set.

MONITOR STRATEGY

MONITOR STRATEGY

Display (DTC Output)

Proceed To

P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138

A

No output

B

DTC

No.

DTC Detection Condition

Trouble Area

P2121

Difference between VPA and VPA2 less than 0.4 V, or more
than 1.2 V for 0.5 seconds (1 trip detection logic)



Accelerator Pedal Position
(APP) sensor



ECM

Related DTCs

P2121: Accelerator pedal position (APP) sensor rationality

Required Sensors/Components (Main)

APP sensor

Required Sensors/Components (Related)

-

Frequency of Operation

Continuous

Duration

0.5 seconds

MIL Operation

Immediate

Sequence of Operation

None

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

FAIL-SAFE

The accelerator pedal position sensor has two (main and sub) sensor circuits. If a malfunction occurs in either of
the sensor circuits, the ECM detects the abnormal signal voltage difference between the two sensor circuits and
switches to limp mode. In limp mode, the functioning circuit is used to calculate the accelerator pedal opening
angle to allow the vehicle to continue driving. If both circuits malfunction, the ECM regards the opening angle
of the accelerator pedal as being fully closed. In this case, the throttle valve remains closed as if the engine is
idling.

If a pass condition is detected and then the ignition switch is turned OFF, the fail-safe operation stops and the
system returns to a normal condition.

WIRING DIAGRAM

Refer to DTC P2120 .

INSPECTION PROCEDURE

HINT:



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.



This DTC relates to the Accelerator Pedal Position (APP) sensor.

1. READ VALUE USING TECHSTREAM (ACCELERATOR POSITION SENSOR) (See

INSPECTION PROCEDURE )

A : Go to step 3

B : Go to next step.

Monitor runs whenever following DTCs are not present

None

Either of following conditions 1 or 2 met:

-

1. Ignition switch

ON

2. Electronic throttle actuator power

ON

Difference between VPA voltage (learned value) and VPA2 voltage
(learned value)

Less than 0.4 V, or more than
1.2 V

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

2. CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR -

ECM) (See INSPECTION PROCEDURE )

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go to next step.

3. REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

a. Replace the accelerator pedal rod assembly (See REMOVAL ).

4. CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR

DTCS)

a. Connect the Techstream to the DLC3.

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

c. Clear DTCs (See DIAGNOSTIC TROUBLE CODE CHART ).

d. Start the engine.

e. Allow the engine to idle for 15 seconds.

f. Enter the following menus: Powertrain/Engine and ECT/Trouble Codes.

g. Read the DTCs.

Result

RESULT CHART

B : SYSTEM OK

A : REPLACE ECM (See REMOVAL )

DTC P2195 OXYGEN (A/F) SENSOR SIGNAL STUCK LEAN (BANK 1 SENSOR 1); DTC P2196
OXYGEN (A/F) SENSOR SIGNAL STUCK RICH (BANK 1 SENSOR 1); DTC P2197 OXYGEN (A/F)
SENSOR SIGNAL STUCK LEAN (BANK 2 SENSOR 1); DTC P2198 OXYGEN (A/F) SENSOR
SIGNAL STUCK RICH (BANK 2 SENSOR 1)

DESCRIPTION

HINT:



Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.



Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located
near the engine assembly.

The A/F sensor generates a voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to

Display (DTC Output) Proceed To

P2121

A

No output

B

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra