2Az-Fe Engine Control System. Dtc P0120 Throttle / Pedal Position Sensor / Switch A Circuit Malfunction

The throttle position sensor is mounted on the throttle with motor body assembly, and detects the opening angle of the throttle valve. This sensor is a non-contact type, and uses Hall-effect elements, in order to yield accurate signals, even in extreme 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.

Camry. Acv40 Gsv40.2Az-Fe Engine Control System.Sfi System.
Dtc
P0120 Throttle / Pedal Position Sensor / Switch A Circuit Malfunction

DTC No.	DTC Detection Condition	Trouble Area
P0120	Output voltage of VTA1 quickly fluctuates beyond lower and upper malfunction thresholds for 2 seconds (1 trip detection logic)	Throttle position sensor (built into throttle with motor body assembly) ECM
P0121	Difference between VTA1 and VTA2 voltages less than 0.8 V, or more than 1.6 V for 2 seconds (1 trip detection logic)	Throttle position sensor (built into throttle with motor body assembly) Throttle position sensor circuit ECM
P0122	Output voltage of VTA1 0.2 V or less for 2 seconds (1 trip detection logic)	Throttle position sensor (built into throttle with motor body assembly) Short in VTA1 circuit Open in VC circuit ECM
P0123	Output voltage of VTA1 4.535 V or more for 2 seconds (1 trip detection logic)	Throttle position sensor (built into throttle with motor body assembly) Open in VTA1 circuit Open in E2 circuit Short between VC and VTA1 circuits ECM
P0220	Output voltage of VTA2 quickly fluctuates beyond lower and upper malfunction thresholds for 2 seconds (1 trip detection logic)	Throttle position sensor (built into throttle with motor body assembly) ECM
P0222	Output voltage of VTA2 1.75 V or less for 2 seconds (1 trip detection logic)	Throttle position sensor (built into throttle with motor body assembly) Short in VTA2 circuit Open in VC circuit ECM
P0223	Output voltage of VTA2 4.8 V or more, and VTA1 between 0.2 V and 2.02 V for 2 seconds (1 trip detection logic)	Throttle position sensor (built into throttle with motor body assembly) Open in VTA2 circuit Open in E2 circuit Short between VC and VTA2 circuits ECM
P2135	Either condition (a) or (b) is met (1 trip detection logic): (a) Difference between output voltages of VTA1 and VTA2 0.02 V or less for 0.5 seconds or more (b) Output voltage of VTA1 0.2 V or less, and VTA2 1.75 V or less for 0.4 seconds or more	Short between VTA1 and VTA2 circuits Throttle position sensor (built into throttle with motor body assembly) ECM

HINT:

When any of these DTCs are set, check the throttle valve opening angle by entering 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 off, and the throttle valve is returned to a 6.5° throttle 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 opening angle, 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. 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 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 SENSOR)

Connect the intelligent tester to the DLC3.

Turn the ignition switch to ON.

Turn the tester on.

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

Read the values displayed on the tester.

Result:

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

HINT:

DTC P0121 is stored when the voltages output from VTA1 and VTA2 are not consistent with the characteristics of the sensors. Therefore, check the Freeze Frame Data when this DTC is output. Use the following formula to confirm relative fluctuations in voltage.
Features of 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 the "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 position sensor 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
C5-5 (VC) - C24-67 (VCTA)	Always	Below 1 Ω
C5-6 (VTA) - C24-115 (VTA1)	Always	Below 1 Ω
C5-4 (VTA2) - C24-114 (VTA2)	Always	Below 1 Ω
C5-3 (E2) - C24-91 (ETA)	Always	Below 1 Ω

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
C5-5 (VC) or C24-67 (VCTA) - Body ground	Always	10 kΩ or higher
C5-6 (VTA) or C24-115 (VTA1) - Body ground	Always	10 kΩ or higher
C5-4 (VTA2) or C24-114 (VTA2) - Body ground	Always	10 kΩ or higher

Reconnect the ECM connector.

Reconnect the throttle position sensor connector.

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

OK

3.INSPECT ECM (VC VOLTAGE)

Disconnect the throttle position sensor 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
C5-5 (VC) - C5-3 (E2)
Ignition switch ON
4.5 to 5.5 V
Text in Illustration
*1
Front view of wire harness connector
(to Throttle Position Sensor)

Text in Illustration
*1	Front view of wire harness connector (to Throttle Position Sensor)

Reconnect the throttle position sensor connector.

REPLACE ECM (CAMRY_ACV40 RM0000017UO02YX.html)

OK

4.REPLACE THROTTLE WITH MOTOR BODY ASSEMBLY

Replace the throttle with motor body assembly (CAMRY_ACV40 RM0000017UD03XX.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 (CAMRY_ACV40 RM000000PDK0LEX.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 are output
A
DTC is not output
B

END

REPLACE ECM (CAMRY_ACV40 RM0000017UO02YX.html)

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

Tester Connection	Switch Condition	Specified Condition
C5-5 (VC) - C5-3 (E2)	Ignition switch ON	4.5 to 5.5 V

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