1Gr-Fe Engine Control. Dtc P2120 Throttle / Pedal Position Sensor / Switch D Circuit

The accelerator pedal position sensor is mounted on the accelerator pedal sensor assembly 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 amount the accelerator pedal is depressed (throttle valve opening angle). The signal from VPA indicates the actual accelerator pedal position (throttle valve opening angle) and is used for engine control. The signal from VPA2 conveys the status of the VPA circuit and is used to check the accelerator pedal position sensor itself.

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

Land Cruiser. Urj200, 202 Grj200 Vdj200.1Gr-Fe Engine Control.Sfi System.
Dtc
P2120 Throttle / Pedal Position Sensor / Switch D Circuit

DTC No.	DTC Detection Condition	Trouble Area
P2120	VPA fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).	Accelerator pedal sensor assembly ECM
P2122	VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1 trip detection logic).	Accelerator pedal sensor assembly Open in VCPA circuit Open or short to ground in VPA circuit ECM
P2123	VPA is 4.8 V or higher for 2.0 seconds or more (1 trip detection logic).	Accelerator pedal sensor assembly Open in EPA circuit ECM
P2125	VPA2 fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic).	Accelerator pedal sensor assembly ECM
P2127	VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1 trip detection logic).	Accelerator pedal sensor assembly Open in VCP2 circuit Open or short to ground in VPA2 circuit ECM
P2128	Conditions (a) and (b) are met for 2.0 seconds or more (1 trip detection logic): (a) VPA2 is 4.8 V or higher. (b) VPA is between 0.4 V and 3.45 V.	Accelerator pedal sensor assembly Open in EPA2 circuit ECM
P2138	Condition (a) or (b) is met 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.	Short between VPA and VPA2 circuits Accelerator pedal sensor assembly ECM

HINT:

When any of these DTCs is output, 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 Accelerator Pedal Released	Accel Sensor Out No.2 When Accelerator Pedal Released	Accel Sensor Out No.1 When Accelerator Pedal Depressed	Accel Sensor Out 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 short to ground 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 short to ground 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	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.

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

FAIL-SAFE

When DTC P2120, P2121, P2122, P2123, P2125, P2127, P2128 or P2138 is stored, the ECM enters fail-safe 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

INSPECTION PROCEDURE

HINT:

These DTCs relate to the accelerator pedal position sensor.
Read freeze frame data using the GTS. 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.

1.READ VALUE USING GTS (ACCEL SENSOR OUT NO.1 AND ACCEL SENSOR OUT NO.2)

Connect the GTS to the DLC3.

Turn the ignition switch to ON and turn the GTS on.

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

Read the value displayed on the GTS.

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	More than 0.02 V

Text in Illustration
*a	Depressed
*b	Released

Go to step 5

Go to step 2

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

Disconnect the accelerator pedal sensor assembly connector.

Disconnect the ECM connector.

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

Standard Resistance:

for LHD
Tester Connection	Condition	Specified Condition
A31-6 (VPA) - A38-55 (VPA)	Always	Below 1 Ω
A31-5 (EPA) - A38-58 (EPA)	Always	Below 1 Ω
A31-4 (VCPA) - A38-57 (VCPA)	Always	Below 1 Ω
A31-3 (VPA2) - A38-56 (VPA2)	Always	Below 1 Ω
A31-2 (EPA2) - A38-60 (EPA2)	Always	Below 1 Ω
A31-1 (VCP2) - A38-59 (VCP2)	Always	Below 1 Ω
A31-6 (VPA) or A38-55 (VPA) - Body ground	Always	10 kΩ or higher
A31-5 (EPA) or A38-58 (EPA) - Body ground	Always	10 kΩ or higher
A31-4 (VCPA) or A38-57 (VCPA) - Body ground	Always	10 kΩ or higher
A31-3 (VPA2) or A38-56 (VPA2) - Body ground	Always	10 kΩ or higher
A31-2 (EPA2) or A38-60 (EPA2) - Body ground	Always	10 kΩ or higher
A31-1 (VCP2) or A38-59 (VCP2) - Body ground	Always	10 kΩ or higher

for RHD
Tester Connection	Condition	Specified Condition
A31-6 (VPA) - A52-55 (VPA)	Always	Below 1 Ω
A31-5 (EPA) - A52-58 (EPA)	Always	Below 1 Ω
A31-4 (VCPA) - A52-57 (VCPA)	Always	Below 1 Ω
A31-3 (VPA2) - A52-56 (VPA2)	Always	Below 1 Ω
A31-2 (EPA2) - A52-60 (EPA2)	Always	Below 1 Ω
A31-1 (VCP2) - A52-59 (VCP2)	Always	Below 1 Ω
A31-6 (VPA) or A52-55 (VPA) - Body ground	Always	10 kΩ or higher
A31-5 (EPA) or A52-58 (EPA) - Body ground	Always	10 kΩ or higher
A31-4 (VCPA) or A52-57 (VCPA) - Body ground	Always	10 kΩ or higher
A31-3 (VPA2) or A52-56 (VPA2) - Body ground	Always	10 kΩ or higher
A31-2 (EPA2) or A52-60 (EPA2) - Body ground	Always	10 kΩ or higher
A31-1 (VCP2) or A52-59 (VCP2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.CHECK ECM (VCPA AND VCP2 VOLTAGE)

Disconnect the accelerator pedal sensor assembly connector.

Turn the ignition switch to ON.

Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
A31-4 (VCPA) - A31-5 (EPA)
Ignition switch ON
4.5 to 5.5 V
A31-1 (VCP2) - A31-2 (EPA2)
Ignition switch ON
4.5 to 5.5 V
Text in Illustration
*a
Front view of wire harness connector
(to Accelerator Pedal Sensor Assembly)

Text in Illustration
*a	Front view of wire harness connector (to Accelerator Pedal Sensor Assembly)

REPLACE ECM (Click here)

OK

4.REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY

Replace the accelerator pedal sensor assembly (Click here).

NEXT

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

Connect the GTS to the DLC3.

Turn the ignition switch to ON and turn the GTS on.

Clear the DTCs (Click here).

Start the engine.

Allow the engine to idle for 15 seconds.

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

Read the DTCs.

Result
Result
Proceed to
P2120, P2122, P2123, P2125, P2127, P2128 and/or P2138 is output
A
No DTC is output
B

Result
Result	Proceed to
P2120, P2122, P2123, P2125, P2127, P2128 and/or P2138 is output	A
No DTC is output	B

SYSTEM OK

REPLACE ECM (Click here)

Tester Connection	Switch Condition	Specified Condition
A31-4 (VCPA) - A31-5 (EPA)	Ignition switch ON	4.5 to 5.5 V
A31-1 (VCP2) - A31-2 (EPA2)	Ignition switch ON	4.5 to 5.5 V