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

DTC Code	DTC Name
P0120	Throttle / Pedal Position Sensor / Switch "A" Circuit
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

CAUTION / NOTICE / HINT

Tip:

These DTCs relate to the throttle position sensor.

DESCRIPTION

The throttle position sensor is mounted on the throttle body assembly, and detects the opening angle of the throttle valve. This sensor is a non-contact type. It uses Hall-effect elements in order to yield accurate signals even in extreme driving conditions such as at high speeds and 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.


DTC No.	DTC Detection Condition	Trouble Area
P0120	The output voltage of VTA1 quickly fluctuates beyond the lower and upper malfunction thresholds for 2 seconds when accelerator pedal is depressed (1 trip detection logic).	Throttle position sensor (built into throttle body assembly) ECM
P0121	The difference between the VTA1 and VTA2 voltages is below 0.8 V, or higher than 1.6 V for 2 seconds (1 trip detection logic).	Throttle position sensor (built into throttle body assembly)
P0122	The output voltage of VTA1 is 0.2 V or less for 2 seconds when the accelerator pedal is depressed (1 trip detection logic).	Throttle position sensor (built into throttle body assembly) Short in VTA1 circuit Open in VC circuit ECM
P0123	The output voltage of VTA1 is 4.535 V or higher for 2 seconds when the accelerator pedal is depressed (1 trip detection logic).	Throttle position sensor (built into throttle body 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 lower and upper malfunction thresholds for 2 seconds when the accelerator pedal is depressed (1 trip detection logic).	Throttle position sensor (built into throttle body assembly) ECM
P0222	The output voltage of VTA2 is 1.75 V or less for 2 seconds when the accelerator pedal is depressed (1 trip detection logic).	Throttle position sensor (built into throttle body 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 when the accelerator pedal is depressed (1 trip detection logic).	Throttle position sensor (built into throttle body 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 circuit Throttle position sensor (built into throttle body assembly) ECM

Tip:

When any of these DTCs are output, check the throttle valve opening angle using the GTS. Enter the following menus: Powertrain / Engine and ECT / Data List / 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)


GTS 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 4.98 V

FAIL-SAFE

When any of these DTCs as well as other DTCs relating to 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 5.5° 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 gently, the vehicle can be driven slowly. Fail-safe mode continues until a pass condition is detected and the ignition switch is turned off.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

Tip:

Read freeze frame data using the GTS. 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.

PROCEDURE

READ VALUE USING GTS (THROTTLE POSITION NO. 1 AND THROTTLE POSITION 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 / Throttle Position No. 1 and Throttle Position No. 2.

Read the values displayed on the GTS.

Table 1. 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 4.98 V	4.5 V to 4.98 V	4.5 V to 4.98 V	4.5 V to 4.98 V	E2 circuit open
0 V to 0.2 V, or 4.5 V to 4.98 V	2.1 V to 3.1 V (Fail-safe)	0 V to 0.2 V, or 4.5 V to 4.98 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 V to 0.2 V, or 4.5 V to 4.98 V	0.6 V to 1.4 V (Fail-safe)	0 V to 0.2 V, or 4.5 V to 4.98 V	VTA2 circuit open or ground short
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 4.98 V (Not fail-safe)	Throttle position sensor circuit normal	B

Tip:

DTC P0121 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.
Calculate the voltage of VTA1 and VTA2 according to Throttle Sensor Volt % and Throttl Sensor #2 Volt % respectively and confirm their consistency.

Example

Throttle Sensor Volt % / 100 (%) x 5 (V) = Throttle Position No.1

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 the "CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)" step.

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

CHECK HARNESS AND CONNECTOR (THROTTLE POSITION SENSOR - ECM)

Disconnect the throttle body 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
C9-5 (VC) - C111-134 (VCTA)	Always	Below 1 Ω
C9-6 (VTA) - C111-135 (VTA1)	Always	Below 1 Ω
C9-4 (VTA2) - C111-101 (VTA2)	Always	Below 1 Ω
C9-3 (E2) - C111-133 (ETA)	Always	Below 1 Ω

Standard Resistance (Check for Short)


Tester Connection	Condition	Specified Condition
C9-5 (VC) or C111-134 (VCTA) - Body ground	Always	10 kΩ or higher
C9-6 (VTA) or C111-135 (VTA1) - Body ground	Always	10 kΩ or higher
C9-4 (VTA2) or C111-101 (VTA2) - Body ground	Always	10 kΩ or higher

Reconnect the throttle body assembly connector.
Reconnect the ECM connector.

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

INSPECT ECM (VC VOLTAGE)

Disconnect the throttle body 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
C9-5 (VC) - C9-3 (E2)	Ignition switch ON	4.5 to 5.5 V

Table 2. Text in Illustration
*a	Front view of wire harness connector (to Throttle Body Assembly)

Reconnect the throttle body assembly connector.

REPLACE ECM

(Click here)

REPLACE THROTTLE BODY ASSEMBLY
1. Replace the throttle body assembly (Click here).
  
  Tip:
  Perform "Inspection After Repair" after replacing the throttle body assembly (Click here).

CHECK WHETHER DTC OUTPUT RECURS (THROTTLE 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 or more.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

Table 3. Result
Result	Proceed to
DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and/or P2135 are output	A
DTC is not output	B

REPLACE ECM

(Click here)

SYSTEM OK