2Tr-Fbe Engine Control. Dtc P0120 Throttle / Pedal Position Sensor / Switch A Circuit Malfunction

The throttle position sensor is built into the throttle body with motor assembly and detects the opening angle of the throttle valve. This sensor is a non-contact type sensor. It 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 throttle position sensor has 2 sensor circuits, each of which transmits a signal, VTA1 and VTA2. VTA1 is used to detect the throttle valve angle and VTA2 is used to detect malfunctions in VTA1. The sensor signal voltages vary between 0 V and 5 V in proportion to the throttle valve opening angle, and are transmitted to the VTA terminals of the ECM.
As the valve closes, the sensor output voltage decreases and as the valve opens, the sensor output voltage increases. The ECM calculates the throttle valve opening angle according to these signals and controls the throttle actuator in response to driver inputs. These signals are also used in calculations such as air fuel ratio correction, power increase correction and fuel-cut control.

Hilux. Tgn26, 36 Kun25, 26, 35, 36 Ggn25.2Tr-Fbe Engine Control.Sfi System.
Dtc
P0120 Throttle / Pedal Position Sensor / Switch A Circuit Malfunction

DTC No.	DTC Detection Condition	Trouble Area
P0120	The output voltage of VTA1 quickly fluctuates beyond the upper and lower malfunction thresholds for 2 seconds or more (1-trip detection logic).	Throttle position sensor (built into throttle body with motor assembly) ECM
P0121	The difference between the VTA1 and VTA2 voltages is less than 0.8 V, or more than 1.6 V for 2 seconds (1-trip detection logic).	Throttle position sensor (built into throttle body with motor assembly) Throttle position sensor circuit ECM
P0122	The output voltage of VTA1 is 0.2 V or less for 2 seconds or more (1-trip detection logic).	Throttle position sensor (built into throttle body with motor assembly) Short in VTA1 circuit Open in VC circuit ECM
P0123	The output voltage of VTA1 is 4.54 V or higher for 2 seconds or more (1-trip detection logic).	Throttle position sensor (built into throttle body with motor assembly) Open in VTA1 circuit Open in E2 circuit Short between VC and VTA1 circuit ECM
P0220	The output voltage of VTA2 quickly fluctuates beyond the upper and lower malfunction thresholds for 2 seconds or more (1-trip detection logic).	Throttle position sensor (built into throttle body with motor assembly) ECM
P0222	The output voltage of VTA2 is 1.75 V or less for 2 seconds or more (1-trip detection logic).	Throttle position sensor (built into throttle body with motor assembly) Short in VTA2 circuit Open in VC circuit ECM
P0223	The output voltage of VTA2 is 4.8 V or higher and VTA1 is between 0.2 V and 2.02 V for 2 seconds or more (1-trip detection logic).	Throttle position sensor (built into throttle body with motor assembly) Open in VTA2 circuit Open in E2 circuit Short between VC and VTA2 circuit ECM
P2135	Either condition is met (1-trip detection logic): (a) The difference between the output voltages of VTA1 and VTA2 is 0.02 V or less for 0.5 seconds or more. (b) The output voltage of VTA1 is 0.2 V or less and VTA2 is 1.75 V or less for 0.4 seconds or more.	Short between VTA1 and VTA2 circuits Throttle position sensor (built into throttle body with motor assembly) ECM

HINT:

When any of these DTCs are output, check the throttle valve opening angle using the intelligent tester.
Enter the following menus: Powertrain / Engine and ECT / Data List / ETCS / Throttle Position No.1 and Throttle Position No.2.
Throttle Position No.1 is the VTA1 signal, and Throttle Position No.2 is the VTA2 signal.

Reference (Normal Condition)
Tester Display	Accelerator Pedal Fully Released	Accelerator Pedal Fully Depressed
Throttle Position No.1	0.5 to 1.1 V	3.2 to 4.8 V
Throttle Position No.2	2.1 to 3.1 V	4.6 to 5.0 V

FAIL-SAFE

When any of these DTCs as well as other DTCs relating to ETCS (Electronic Throttle Control System) malfunctions are stored, the ECM enters fail-safe mode. During fail-safe mode, the ECM cuts the current to the throttle actuator and the throttle valve is returned to a 6.5° opening angle by the return spring. The ECM then adjusts the engine output by controlling the fuel injection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal position to allow the vehicle to continue at a minimal speed. If the accelerator pedal is depressed firmly and gently, the vehicle can be driven slowly.
The ECM continues operating in fail-safe mode until a pass condition is detected and the ignition switch is turned off.

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

Read freeze frame data using the intelligent tester. 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 INTELLIGENT TESTER (THROTTLE POSITION NO.1 AND THROTTLE POSITION NO.2)

Connect the intelligent tester to the DLC3.

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

Enter the following menus: Powertrain / Engine and ECT / Data List / Throttle Position No. 1 and Throttle Position No. 2.

Read the values displayed on the tester.

Result
Throttle Position No. 1 (VTA1) when Accelerator Pedal Released	Throttle Position No.2 (VTA2) when Accelerator Pedal Released	Throttle Position No. 1 (VTA1) when Accelerator Pedal Depressed	Throttle Position No.2 (VTA2) when Accelerator Pedal Depressed	Trouble Area	Proceed to
0 V to 0.2 V	0 V to 0.2 V	0 V to 0.2 V	0 V to 0.2 V	VC circuit open	A
4.5 V to 5.0 V	4.5 V to 5.0 V	4.5 V to 5.0 V	4.5 V to 5.0 V	E2 circuit open
0 V to 0.2 V, or 4.5 V to 5.0 V	2.1 V to 3.1 V (Fail-safe)	0 V to 0.2 V, or 4.5 V to 5.0 V	2.1 V to 3.1 V (Fail-safe)	VTA1 circuit open or short to ground
0.6 V to 1.4 V (Fail-safe)	0 V to 0.2 V, or 4.5 V to 5.0 V	0.6 V to 1.4 V (Fail-safe)	0 V to 0.2 V, or 4.5 V to 5.0 V	VTA2 circuit open or short to ground
0.5 V to 1.1 V	2.1 V to 3.1 V	3.2 V to 4.8 V (Not fail-safe)	4.6 V to 5.0 V (Not fail-safe)	Throttle position sensor circuit normal	B

HINT:

DTC P0121/41 is stored when the VTA1 and VTA2 output voltages are not consistent with the sensor characteristics. Therefore, check the freeze frame data when this DTC is output. Use the following formula to confirm the relative differences in voltage.

Characteristic Sensor Output:

VTA2 x 0.8 is approximately equal to VTA1 + 1.11 V
VTA1: Throttle Position No. 1
VTA2: Throttle Position No. 2

If DTC P0121 is output, proceed to "Check Harness and Connector (Throttle Position Sensor - ECM)".

Go to step 5

A

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

Disconnect the throttle body with motor assembly connector.

Disconnect the ECM connector.

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

Standard Resistance (Check for Open):

Tester Connection	Condition	Specified Condition
C67-5 (VC) - C95-10 (VCTA)	Always	Below 1 Ω
C67-6 (VTA) - C95-3 (VTA1)	Always	Below 1 Ω
C67-4 (VTA2) - C95-4 (VTA2)	Always	Below 1 Ω
C67-3 (E2) - C95-9 (ETA)	Always	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
C67-5 (VC) or C95-10 (VCTA) - Body ground	Always	10 kΩ or higher
C67-6 (VTA) or C95-3 (VTA1) - Body ground	Always	10 kΩ or higher
C67-4 (VTA2) or C95-4 (VTA2) - Body ground	Always	10 kΩ or higher

Reconnect the throttle body with motor assembly connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (THROTTLE POSITION SENSOR - ECM)

OK

3.INSPECT ECM (VC VOLTAGE)

Disconnect the throttle body with motor assembly connector.

Measure the voltage according to the value(s) in the table below.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
C67-5 (VC) - C67-3 (E2)
Ignition switch ON
4.5 to 5.5 V
Text in Illustration
*a
Front view of wire harness connector
(to Throttle Body with Motor Assembly)

Text in Illustration
*a	Front view of wire harness connector (to Throttle Body with Motor Assembly)

Reconnect the throttle body with motor assembly connector.

REPLACE ECM (HILUX_TGN26 RM000000VW2024X.html)

OK

4.REPLACE THROTTLE BODY WITH MOTOR ASSEMBLY

Replace the throttle body with motor assembly (HILUX_TGN26 RM000000VWO01YX.html).

NEXT

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

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

Clear the DTCs (HILUX_TGN26 RM000000PDK12LX.html).

Start the engine.

Allow the engine to idle for 15 seconds or more.

Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.

Result
Result
Proceed to
DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and/or P2135 is output
A
DTC is not output
B

Result
Result	Proceed to
DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and/or P2135 is output	A
DTC is not output	B

END

REPLACE ECM (HILUX_TGN26 RM000000VW2024X.html)

Tester Connection	Switch Condition	Specified Condition
C67-5 (VC) - C67-3 (E2)	Ignition switch ON	4.5 to 5.5 V