SFI SYSTEM, Diagnostic DTC:P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135

DTC Code	DTC Name
P0120	Throttle / Pedal Position Sensor / Switch "A" Circuit Malfunction
P0121	Throttle / Pedal Position Sensor / Switch "A" Circuit Range / Performance Problem
P0122	Throttle / Pedal Position Sensor / Switch "A" Circuit Low Input
P0123	Throttle / Pedal Position Sensor / Switch "A" Circuit High Input
P0220	Throttle / Pedal Position Sensor / Switch "B" Circuit
P0222	Throttle / Pedal Position Sensor / Switch "B" Circuit Low Input
P0223	Throttle / Pedal Position Sensor / Switch "B" Circuit High Input
P2135	Throttle / Pedal Position Sensor / Switch "A" / "B" Voltage Correlation

DESCRIPTION

Tech Tips

This ETCS (Electronic Throttle Control System) does not use a throttle cable.

The Throttle Position (TP) sensor is mounted on the throttle body, 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 driving conditions, such as at high speeds as well as very low speeds.

The TP sensor has two sensor circuit, each of which transmits a signal, VTA and VTA2. VTA is used to detect the throttle valve angle and VTA2 is used to detect malfunctions in VTA. 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.

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

Tech Tips

When any of these DTCs are set, check the throttle valve opening angle by entering the following menus on the intelligent tester: Powertrain / Engine / Data List / Throttle Position No. 1and Throttle Position No. 2.

Throttle Position No. 1denotes the VTA signal, and Throttle Position No. 2 denotes 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	4.5 to 5.0 V

MONITOR DESCRIPTION

P0120, P0122, P0123, P0220, P0222, P0223, P2135

The ECM uses the Throttle Position (TP) sensor to monitor the throttle valve opening angle. There are several checks that the ECM performs to confirm the proper operation of the TP sensor.

A specific voltage difference is expected between the sensor terminals, VTA and VTA2, for each throttle valve opening angle. If the difference between VTA and VTA2 is incorrect, the ECM interprets this as a malfunction in the sensor, and sets a DTC.
VTA and VTA2 each have a specific voltage range. If VTA or VTA2 is outside the normal operating range, the ECM interprets this as a malfunction in the sensor, and sets a DTC.
VTA and VTA2 should never be close to the same voltage level. If VTA is within 0.02 V of VTA2, the ECM determines that there is a short circuit in the sensor, and sets a DTC.

If the malfunction is not repaired successfully, a DTC is stored 10 seconds after the engine is next started.

P0121

This sensor transmits 2 signals: VTA and VTA2. VTA is used to detect the throttle opening angle and VTA2 is used to detect malfunctions in VTA. The ECM performs several checks to confirm the proper operation of the throttle position sensor and VTA.

For each throttle opening angle, a specific voltage difference is expected between the outputs of VTA and VTA2. If the output voltage difference between the 2 signals deviates from the normal operating range, the ECM interprets this as a malfunction in the throttle position sensor. The ECM illuminates the MIL and sets a DTC.

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

FAIL-SAFE

When any of these DTCs, as well as other DTCs relating to ETCS (Electronic Throttle Control System) malfunctions, are set, 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 7° 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.

WIRING DIAGRAM


*a	Throttle Position Sensor

CAUTION / NOTICE / HINT

Tech Tips

If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
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.

PROCEDURE

READ VALUE USING INTELLIGENT TESTER (THROTTLE POSITION NO.1 AND THROTTLE POSITION NO.2)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG) and turn the tester ON.
Enter the following menus: Powertrain / Engine / Data List / Throttle Position No. 1 and Throttle Position No. 2.
While the accelerator pedal is fully closed, read the values of Throttle Position No.1 and Throttle Position No.2.
Start the engine.

Read the value displayed on the tester.

Result

Throttle Position No. 1 When Accelerator Pedal Released	Throttle Position No. 2 When Accelerator Pedal Released	Throttle Position No. 1 When Accelerator Pedal Depressed	Throttle Position No. 2 When Accelerator Pedal Depressed	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	A
0 to 0.2 V, or 4.5 to 5.0 V	2.1 to 3.1 V (Fail-safe)	0 to 0.2 V, or 4.5 to 5.0 V	2.1 to 3.1 V (Fail-safe)	VTA circuit open or ground short	A
0.5 to 1.1 V (Fail-safe)	0 to 0.2 V, or 4.5 to 5.0 V	0.5 to 1.1 V (Fail-safe)	0 to 0.2 V, or 4.5 to 5.0 V	VTA2 circuit open or ground short	A
0.5 to 1.1 V	2.1 to 3.1 V	3.2 to 4.8 V (Not fail-safe)	4.5 to 5.0 V (Not fail-safe)	Throttle position sensor circuit normal	B

Tech Tips

DTC P0121 is stored when the voltages output from VTA 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 VTA + 1.11 V
VTA: Throttle Position No. 1
VTA2: Throttle Position No. 2

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

CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS) Click here

CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)

Disconnect the E21 throttle body connector.


*1	Front view of wire harness connector: (to Throttle Position Sensor)
*2	ECM Connector

Disconnect the E2 ECM connector.

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

Standard resistance (Check for open)

Tester Connection	Condition	Specified Condition
E21-5 (VC) - E2-34 (VCTA)	Always	Below 1 Ω
E21-6 (VTA) - E2-26 (VTA)	Always	Below 1 Ω
E21-4 (VTA2) - E2-27 (VTA2)	Always	Below 1 Ω
E21-3 (E2) - E2-35 (ETA)	Always	Below 1 Ω

Standard resistance (Check for short)

Tester Connection	Condition	Specified Condition
E21-5 (VC) or E2-34 (VCTA)- Body ground	Always	10 kΩ or higher
E21-6 (VTA) or E2-26 (VTA) - Body ground	Always	10 kΩ or higher
E21-4 (VTA2) or E2-27 (VTA2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

INSPECT ECM (VCTA VOLTAGE)

Disconnect the E21 throttle body connector.
Turn the engine switch on (IG).

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

Standard voltage

Tester Connection	Switch Condition	Specified Condition
E2-34 (VCTA) - E2-35 (ETA)	Engine switch on (IG)	4.5 to 5.0 V

REPLACE ECM Click here

REPLACE THROTTLE BODY
1. Replace the throttle body Click here.
NEXT

CHECK WHETHER DTC OUTPUT RECURS (THROTTLE POSITION SENSOR DTCS)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG) and turn the tester ON.
Clear DTCs Click here.
Start the engine.
Allow the engine to idle for 15 seconds or more.
Enter the following menus: Powertrain / Engine / DTC.

Read DTCs.

Result

Display (DTC Output)	Proceed to
P0120, P0121, P0122, P0123, P0220, P0223, and/or P2135	A
No output	B

REPLACE ECM Click here

SYSTEM OK