Brand:

Toyota

Model Name:

Yaris NCP90 91 92 93

Manual:

Repair Manual

Section:

1Nz-Fe Engine Control System

Title:

Sfi System

  1. Description

  2. Fail-safe

  3. Wiring diagram

  4. Inspection procedure

  5. Read value using intelligent tester (accelerator position no. 1 and accelerator position no. 2)

  6. Check harness and connector (accelerator pedal position sensor - ecm)

  7. Inspect ecm (vcpa and vcp2 voltage)

  8. Replace accelerator pedal assembly

  9. Check whether dtc output recurs (accelerator pedal position sensor dtcs)

DTC P2120 Throttle / Pedal Position Sensor / Switch "D" Circuit

DTC P2122 Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input

DTC P2123 Throttle / Pedal Position Sensor / Switch "D" Circuit High Input

DTC P2125 Throttle / Pedal Position Sensor / Switch "E" Circuit

DTC P2127 Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input

DTC P2128 Throttle / Pedal Position Sensor / Switch "E" Circuit High Input

DTC P2138 Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation

HINT:
  1. These DTCs relate to the Accelerator Pedal Position (APP) sensor.
  2. This ETCS (Electronic Throttle Control System) does not use a throttle cable.

DESCRIPTION

The APP 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 V and 5 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.

APP sensor Yaris


DTC No.
DTC Detection Conditions
Trouble Areas
P2120
VPA fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic)
  1. APP sensor
  2. ECM
P2122
VPA 0.4 V or less for 0.5 seconds or more when accelerator pedal fully released (1 trip detection logic)
  1. APP sensor
  2. Open in VCP1 circuit
  3. Open or ground short in VPA circuit
  4. ECM
P2123
VPA 4.8 V or more for 2.0 seconds or more
(1 trip detection logic)
  1. APP sensor
  2. Open in EPA circuit
  3. ECM
P2125
VPA2 fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic)
  1. APP sensor
  2. ECM
P2127
VPA2 1.2 V or less for 0.5 seconds or more when accelerator pedal fully released (1 trip detection logic)
  1. APP sensor
  2. Open in VCP2 circuit
  3. Open or ground short in VPA2 circuit
  4. 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
  1. APP sensor
  2. Open in EPA2 circuit
  3. 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
  1. Short between VPA and VPA2 circuits
  2. APP sensor
  3. ECM

HINT:
When any of these DTCs are set, check the APP sensor voltage by selecting the following menu items on an intelligent tester: Powertrain / Engine and ECT / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.

Trouble Areas
Accelerator Position No. 1
When Accelerator Pedal Released
Accelerator Position No. 2
When Accelerator Pedal Released
Accelerator Position No. 1
When Accelerator Pedal Depressed
Accelerator Position No. 2
When Accelerator Pedal 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 5.0 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 5.0 V

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 circuit 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


Connect an intelligent tester to the DLC3. Yaris


INSPECTION PROCEDURE

HINT:
Read freeze frame data using an intelligent tester. Freeze frame data record 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 INTELLIGENT TESTER (ACCELERATOR POSITION NO. 1 AND ACCELERATOR POSITION NO. 2)
Connect an intelligent tester to the DLC3. Yaris

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Select the following menu items: Powertrain / Engine and ECT / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.

  1. Read the value displayed on the tester.

    Standard voltage:
    Accelerator Pedal Operations
    		Accelerator Position No. 1
    		Accelerator Position No. 2
    Released → Depressed → Released
    		0.5 to 4.5 V
    		1.2 to 5.0 V
    Difference between Accelerator Position No. 1 and Accelerator Position No. 2 is greater than 0.02 V
    		Difference between Accelerator Position No. 1 and Accelerator Position No. 2 is greater than 0.02 V


OKnext
Go to step 5
NG
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2.CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)
Disconnect the A20 Accelerator Pedal Position (APP) sensor connector. Yaris

  1. Disconnect the A20 Accelerator Pedal Position (APP) sensor connector.

  1. Disconnect the A21 ECM connector.

  1. Check the resistance.

    Standard resistance (Check for open):
    Tester Connections
    		Specified Conditions
    VPA (A20-6) - VPA (A21-55)
    		Below 1 Ω
    EPA (A20-5) - EPA (A21-59)
    VCPA (A20-4) - VCPA (A21-57)
    VPA2 (A20-3) - VPA2 (A21-56)
    EPA2 (A20-2) - EPA2 (A21-60)
    VCP2 (A20-1) - VCP2 (A21-58)
    Standard resistance (Check for short):
    Tester Connections
    		Specified Conditions
    VPA (A20-6) or VPA (A21-55) - Body ground
    		10 kΩ or higher
    EPA (A20-5) or EPA (A21-59) - Body ground
    VCPA (A20-4) or VCPA (A21-57) - Body ground
    VPA2 (A20-3) or VPA2 (A21-56) - Body ground
    EPA2 (A20-2) or EPA2 (A21-60) - Body ground
    VCP2 (A20-1) or VCP2 (A21-58) - Body ground

  1. Reconnect the APP sensor connector.

  1. Reconnect the ECM connector.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
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3.INSPECT ECM (VCPA AND VCP2 VOLTAGE)
Disconnect the A20 APP sensor connector. Yaris

  1. Disconnect the A20 APP sensor connector.

  1. Turn the ignition switch to ON.

  1. Measure the voltage between the terminals of the A20 APP sensor connector.

    Standard voltage:
    Tester Connections
    		Specified Conditions
    VCPA (A20-4) - EPA (A20-5)
    		4.5 to 5.5 V
    VCP2 (A20-1) - EPA2 (A20-2)

  1. Reconnect the APP sensor connector.



NGnext
REPLACE ECM (Click here)
OK
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4.REPLACE ACCELERATOR PEDAL ASSEMBLY
Click here

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

  1. Connect an intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Clear DTCs (Click here).

  1. Start the engine.

  1. Allow the engine to idle for 15 seconds.

  1. Select the following menu items: Powertrain / Engine and ECT / DTC.

  1. Read DTCs.

    Result:
    Display (DTC Output)
    		Proceed To
    P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138
    		A
    No output
    		B


Bnext
SYSTEM OK
A
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REPLACE ECM (Click here)