READ VALUE USING INTELLIGENT TESTER (ACCEL POS #1 AND ACCEL POS #2)
CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)
INSPECT ACCELERATOR POSITION SENSOR (VCPA AND VCP2 VOLTAGE)
REPLACE ACCELERATOR PEDAL ROD ASSEMBLY
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 |
DESCRIPTION
This ETCS (Electronic Throttle Control System) does not use a throttle cable.The Accelerator Pedal Position (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.

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) |
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P2122 | VPA is 0.4 V or less for 0.5 seconds or more when accelerator pedal is fully released (1 trip detection logic) |
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P2123 | VPA is 4.8 V or more for 2.0 seconds or more (1 trip detection logic) |
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P2125 | VPA2 fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic) |
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P2127 | VPA2 is 1.2 V or less for 0.5 seconds or more when accelerator pedal is fully released (1 trip detection logic) |
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P2128 | Conditions (a) and (b) continue for 2.0 seconds or more (1 trip detection logic): (a) VPA2 is 4.8 V or more (b) VPA is between 0.4 V and 3.45 V |
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P2138 | Condition (a) or (b) continues for 2.0 seconds or more (1 trip detection logic): (a) Difference between VPA and VPA2 is 0.02 V or less (b) VPA is 0.4 V or less and VPA2 is 1.2 V or less |
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- HINT:
- When any of these DTCs are set, check the APP sensor voltage by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.
Trouble Area | ACCEL POS #1 When AP Released | ACCEL POS #2 When AP Released | ACCEL POS #1 When AP Depressed | ACCEL POS #2 When AP Depressed |
VCP circuit open | 0 to 0.4 V | 0 to 1.2 V | 0 to 0.4 V | 0 to 1.2 V |
Open or ground short in VPA circuit | 0 to 0.4 V | 1.2 to 2.0 V | 0 to 0.4 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 |
- HINT:
- Accelerator pedal positions are expressed as voltages.
- AP denotes Accelerator Pedal.
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 then turned off.
WIRING DIAGRAM

INSPECTION PROCEDURE
- HINT:
- Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air-fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction (CAMRY_ACV40 RM000000PDS01FX.html).
- These DTCs relate to the Accelerator Pedal Position (APP) sensor.
1.READ VALUE USING INTELLIGENT TESTER (ACCEL POS #1 AND ACCEL POS #2) |
Connect the intelligent tester to the DLC3.
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Turn the ignition switch to the ON position and turn the tester on.
Enter the following menus: Powertrain / Engine / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.
Read the value displayed on the tester.
- Standard voltage:
Accelerator Pedal Operation ACCEL POS #1
(AP#1)ACCEL POS #2
(AP#2)Released 0.5 to 1.1 V 1.2 to 2.0 V Depressed 2.6 to 4.5 V 3.4 to 5.0 V
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NG | |
2.CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM) |
Disconnect the A17 Accelerator Pedal Position (APP) sensor connector.
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Disconnect the A24 (RHD) or A55 (LHD) ECM connector.
Measure the resistance according to the value(s) in the table below.
- Standard resistance (Check for open):
- RHD:
Tester Connection Specified Condition VPA (A17-6) - VPA (A24-55) Below 1 Ω EPA (A17-5) - EPA (A24-59) Below 1 Ω VCPA (A17-4) - VCPA (A24-57) Below 1 Ω VPA2 (A17-3) - VPA2 (A24-56) Below 1 Ω EPA2 (A17-2) - EPA2 (A24-60) Below 1 Ω VCP2 (A17-1) - VCP2 (A24-58) Below 1 Ω - LHD:
Tester Connection Specified Condition VPA (A17-6) - VPA (A55-55) Below 1 Ω EPA (A17-5) - EPA (A55-59) Below 1 Ω VCPA (A17-4) - VCPA (A55-57) Below 1 Ω VPA2 (A17-3) - VPA2 (A55-56) Below 1 Ω EPA2 (A17-2) - EPA2 (A55-60) Below 1 Ω VCP2 (A17-1) - VCP2 (A55-58) Below 1 Ω
- Standard resistance (Check for short):
- RHD:
Tester Connection Specified Condition VPA (A17-6) or VPA (A24-55) - Body ground 10 kΩ or higher EPA (A17-5) or EPA (A24-59) - Body ground 10 kΩ or higher VCPA (A17-4) or VCPA (A24-57) - Body ground 10 kΩ or higher VPA2 (A17-3) or VPA2 (A24-56) - Body ground 10 kΩ or higher EPA2 (A17-2) or EPA2 (A24-60) - Body ground 10 kΩ or higher VCP2 (A17-1) or VCP2 (A24-58) - Body ground 10 kΩ or higher - LHD:
Tester Connection Specified Condition VPA (A17-6) or VPA (A55-55) - Body ground 10 kΩ or higher EPA (A17-5) or EPA (A55-59) - Body ground 10 kΩ or higher VCPA (A17-4) or VCPA (A55-57) - Body ground 10 kΩ or higher VPA2 (A17-3) or VPA2 (A55-56) - Body ground 10 kΩ or higher EPA2 (A17-2) or EPA2 (A55-60) - Body ground 10 kΩ or higher VCP2 (A17-1) or VCP2 (A55-58) - Body ground 10 kΩ or higher
Reconnect the APP sensor connector.
Reconnect the ECM connector.
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OK | |
3.INSPECT ACCELERATOR POSITION SENSOR (VCPA AND VCP2 VOLTAGE) |
Disconnect the A17 APP sensor connector.
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Turn the ignition switch to the ON position.
Measure the voltage according to the value(s) in the table below.
- Standard voltage:
Tester Connection Specified Condition VCPA (A17-4) - EPA (A17-5) 4.5 to 5.0 V VCP2 (A17-1) - EPA2 (A17-2) 4.5 to 5.0 V
Reconnect the APP sensor connector.
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OK | |
4.REPLACE ACCELERATOR PEDAL ROD ASSEMBLY |
NEXT | |
5.CHECK WHETHER DTC OUTPUT RECURS (ACCELERATOR PEDAL POSITION SENSOR DTCS) |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to the ON position and turn the tester on.
Clear the DTCs (CAMRY_ACV40 RM000000PDK080X.html).
Start the engine.
Allow the engine to idle for 15 seconds.
Enter the following menus: Powertrain / Engine / DTC.
Read the DTCs.
- Result:
Display (DTC Output) Proceed to P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 A No output B
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A | ||
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