Toyota Tundra Service Manual: Throttle / Pedal Position Sensor / Switch "D" Circuit (P2120,P2122,P2123,P2125,P2127,P2128,P2138)

Toyota Tundra Service Manual / Engine, Hybrid System / 1ur-fe Engine Control / Sfi System / Throttle / Pedal Position Sensor / Switch "D" Circuit (P2120,P2122,P2123,P2125,P2127,P2128,P2138)

DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type and 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 voltage, which is applied to terminals VPA and VPA2 of the ECM, varies between 0.5 V and 4.75 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the APP sensor itself.

The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

HINT:

This ETCS (Electronic Throttle Control System) does not use a throttle cable.

DTC No.

DTC Detection Condition

Trouble Area

P2120

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

  • Accelerator pedal sensor assembly
  • ECM

P2122

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

  • Accelerator pedal sensor assembly
  • Open in VCP1 circuit
  • Open or ground short in VPA circuit
  • ECM

P2123

VPA 4.8 V or more for 2.0 seconds or more

(1 trip detection logic)

  • Accelerator pedal sensor assembly
  • 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)

  • Accelerator pedal sensor assembly
  • ECM

P2127

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

  • Accelerator pedal sensor assembly
  • 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

  • Accelerator pedal sensor assembly
  • 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
  • Accelerator pedal sensor assembly
  • ECM

HINT:

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

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 4.75 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 4.98 V

4.5 to 4.98 V

4.5 to 4.98 V

4.5 to 4.98 V

Normal condition

0.5 to 1.1 V

1.2 to 2.0 V

2.6 to 4.5 V

3.4 to 4.75 V

HINT:

  • Accelerator pedal positions are expressed as voltages.
  • AP stands for Accelerator Pedal.

MONITOR DESCRIPTION

When the output voltage of either 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 accelerator pedal position 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

Related DTCs

P2120: Accelerator pedal position (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

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs not present

None

Either of following conditions 1 or 2 met:

-

1. Ignition switch off to ON

0.012 seconds or more

2. Throttle actuator power

ON

TYPICAL MALFUNCTION THRESHOLDS

P2120

Either of the following conditions is met:

1 or 2

1. All of following conditions met:

(a) and (b)

(a) VPA voltage

0.4 V or less

(b) VPA2 voltage - Learned VPA2 accelerator off position voltage

0.04 V or more

2. VPA voltage

4.8 V or more

P2122

All of following conditions met:

(a) and (b)

(a) VPA voltage

0.4 V or less

(b) VPA2 voltage - Learned VPA2 accelerator off position voltage

0.04 V or more

P2123

VPA voltage

4.8 V or more

P2125

Either of the following conditions is met:

1 or 2

1. All of following conditions met:

(a) and (b)

(a) VPA2 voltage

1.2 V or less

(b) VPA voltage - Learned VPA accelerator off position voltage

0.04 V or more

2. VPA2 voltage when VPA voltage 0.4 V or more, and 3.45 V or less

4.8 V or more

P2127

All of following conditions met:

(a) and (b)

(a) VPA2 voltage

1.2 V or less

(b) VPA voltage - Learned VPA accelerator off position voltage

0.04 V or more

P2128

VPA2 voltage when VPA voltage 0.4 V or more, and 3.45 V or less

4.8 V or more

P2138

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

COMPONENT OPERATING RANGE

VPA voltage

0.4 to 4.8 V

VPA2 voltage

1.2 to 4.8 V

Difference between VPA and VPA2 voltages

More than 0.02 V

CONFIRMATION DRIVING PATTERN

  1. Connect the Techstream to the DLC3.
  2. Turn the ignition switch to ON and turn the Techstream on.
  3. Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
  4. Turn the ignition switch off and wait for at least 30 seconds.
  5. Turn the ignition switch to ON and turn the Techstream on [A].
  6. Fully depress and release the accelerator pedal [B].
  7. Check that 5 seconds or more have elapsed since the ignition switch was turned to ON.
  8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
  9. Read the pending DTCs.

    HINT:

    • If a pending DTC is output, the system is malfunctioning.
    • If a pending DTC is not output, perform the following procedure.
  10. Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
  11. Input the DTC: P2120, P2122, P2123, P2125, P2127, P2128 or P2138.
  12. Check the DTC judgment result.

    Tester Display

    Description

    NORMAL

    • DTC judgment completed
    • System normal

    ABNORMAL

    • DTC judgment completed
    • System abnormal

    INCOMPLETE

    • DTC judgment not completed
    • Perform driving pattern after confirming DTC enabling conditions

    N/A

    • Unable to perform DTC judgment
    • Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    • If the judgment result shows ABNORMAL, the system has a malfunction.
    • If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [C] again.
  13. If no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    HINT:

    • If a permanent DTC is output, the system is malfunctioning.
    • If no permanent DTC is output, the system is normal.

FAIL-SAFE

When DTC P2120, P2121, P2122, P2123, P2125, P2127, P2128 or P2138 is stored, the ECM enters failsafe mode. If either of the 2 sensor circuits malfunctions, the ECM limits the engine output. 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

CAUTION / NOTICE / HINT

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.

PROCEDURE

1.

READ VALUE USING TECHSTREAM (ACCELERATOR PEDAL POSITION SENSOR)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

(e) Read the value displayed on the Techstream.

Standard Voltage:

Accelerator Pedal Operation

Accel Sensor Out No. 1

Accel Sensor Out No. 2

Difference between Accel Sensor Out No. 1 and Accel Sensor Out No. 2

Released

0.5 to 1.1 V

1.2 to 2.0 V

More than 0.02 V

Depressed

2.6 to 4.5 V

3.4 to 4.75 V

Result

Result

Proceed to

NG

A

OK

B

B

GO TO STEP 5

A

2.

CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)

(a) Disconnect the APP sensor connector.

(b) Disconnect the ECM connector.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

A60-6 (VPA) - A24-55 (VPA)

Always

Below 1 Ω

A60-5 (EPA) - A24-58 (EPA)

Always

Below 1 Ω

A60-4 (VCPA) - A24-57 (VCPA)

Always

Below 1 Ω

A60-3 (VPA2) - A24-56 (VPA2)

Always

Below 1 Ω

A60-2 (EPA2) - A24-60 (EPA2)

Always

Below 1 Ω

A60-1 (VCP2) - A24-59 (VCP2)

Always

Below 1 Ω

A60-6 (VPA) or A24-55 (VPA) - Body ground

Always

10 kΩ or higher

A60-5 (EPA) or A24-58 (EPA) - Body ground

Always

10 kΩ or higher

A60-4 (VCPA) or A24-57 (VCPA) - Body ground

Always

10 kΩ or higher

A60-3 (VPA2) or A24-56 (VPA2) - Body ground

Always

10 kΩ or higher

A60-2 (EPA2) or A24-60 (EPA2) - Body ground

Always

10 kΩ or higher

A60-1 (VCP2) or A24-59 (VCP2) - Body ground

Always

10 kΩ or higher

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.

INSPECT ECM (VCPA AND VCP2 VOLTAGE)

(a) Disconnect the accelerator pedal position (APP) sensor connector.

(b) Turn the ignition switch to ON.

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

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A60-4 (VCPA) - A60-5 (EPA)

Ignition switch ON

4.5 to 5.5 V

A60-1 (VCP2) - A60-2 (EPA2)

Ignition switch ON

4.5 to 5.5 V

NG

REPLACE ECM

OK

4.

REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY

(a) Replace the accelerator pedal sensor assembly (See page ).

NEXT

5.

CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Clear DTCs (See page ).

(e) Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

(f) Read DTCs.

Result

Result

Proceed to

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

A

No DTC is output

B

A

REPLACE ECM

B

END

    Throttle Actuator Control Throttle Body Range / Performance (P2119)

    Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance (P2121)

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