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

The APP sensor is mounted on the accelerator pedal bracket 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 V and 5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the APP sensor itself.
The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

Yaris. Ncp93, 131.1Nz-Fe Engine Control.Sfi System (For Sedan).
Dtc
P2120 Throttle / Pedal Position Sensor / Switch D Circuit

DTC No.	DTC Detection Condition	Trouble Area
P2120	VPA fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic)	Accelerator pedal assembly ECM
P2122	VPA 0.4 V or less for 0.5 seconds or more when accelerator pedal depressed (1 trip detection logic)	Accelerator pedal assembly Open in VCP1 circuit Open or ground short in VPA circuit ECM
P2123	VPA 4.8 V or more for 2.0 seconds or more (1 trip detection logic)	Accelerator pedal assembly Open in EPA circuit ECM
P2125	VPA2 fluctuates rapidly beyond upper and lower malfunction thresholds for 0.5 seconds or more (1 trip detection logic)	Accelerator pedal assembly ECM
P2127	VPA2 1.2 V or less for 0.5 seconds or more when accelerator pedal depressed (1 trip detection logic)	Accelerator pedal assembly Open in VCP2 circuit Open or ground short in VPA2 circuit ECM
P2128	Conditions (a) and (b) continue for 2.0 seconds or more (1 trip detection logic): (a) VPA2 4.8 V or more (b) VPA between 0.4 V and 3.45 V	Accelerator pedal assembly Open in EPA2 circuit ECM
P2138	Condition (a) or (b) continues for 2.0 seconds or more (1 trip detection logic): (a) Difference between VPA and VPA2 0.02 V or less (b) VPA 0.4 V or less and VPA2 1.2 V or less	Accelerator pedal assembly Short between VPA and VPA2 circuits ECM

HINT:

When any of these DTCs are stored, check the APP sensor voltage by entering the following menus on the Techstream: Powertrain / Engine and ECT / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

Trouble Area	When Accelerator Pedal Released		When Accelerator Pedal Depressed
Trouble Area	Accel Sensor Out No. 1	Accel Sensor Out No. 2	Accel Sensor Out No. 1	Accel Sensor Out No. 2
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 ground short in VPA circuit	0 to 0.2 V	1.2 to 2.0 V	0 to 0.2 V	3.4 to 4.7 V
Open or ground short 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 5.0 V	4.5 to 5.0 V	4.5 to 5.0 V	4.5 to 5.0 V
Normal condition	0.5 to 1.1 V	1.2 to 2.0 V	2.6 to 4.5 V	3.4 to 4.7 V

HINT:

Accelerator pedal positions are expressed as voltages.

MONITOR DESCRIPTION

When either output voltage of 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 APP sensor. The ECM then illuminates the MIL and stores a DTC.
Example:
When the output voltage of VPA drops below 0.4 V for more than 0.5 seconds when the accelerator pedal is fully depressed, DTC P2122 is stored.
If the malfunction is not repaired successfully, a DTC is stored 2 seconds after the engine is next started.

MONITOR STRATEGY

Related DTCs	P2120: APP sensor 1 range check (fluctuating) P2122: APP sensor 1 range check (low voltage) P2123: APP sensor 1 range check (high voltage) P2125: APP sensor 2 range check (fluctuating) P2127: APP sensor 2 range check (low voltage) P2128: APP sensor 2 range check (high voltage) P2138: APP sensor range check (correlation)
Required Sensors/Components (Main)	APP sensor
Required Sensors/Components (Related)	-
Frequency of Operation	Continuous
Duration	0.5 seconds: P2120, P2122, P2125 and P2127 2.0 seconds: P2123, P2128 and P2138
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Monitor runs whenever following DTCs not present	None
Either of following conditions 1 or 2 met:	-
1. Ignition switch	ON (0.012 seconds or more)
2. Throttle actuator power	ON

TYPICAL MALFUNCTION THRESHOLDS

P2120:
Either of following conditions met:	1 or 2
1. All of following conditions met:	(a) and (b)
(a) VPA voltage	0.4 V or less
(b) VPA2 voltage - Learned VPA2 accelerator off position voltage	0.04 V or higher
2. VPA voltage	4.8 V or higher

P2122:
All of following conditions met:	(a) and (b)
(a) VPA voltage	0.4 V or less
(b) VPA2 voltage - Learned VPA2 accelerator off position voltage	0.04 V or higher

P2123:
VPA voltage	4.8 V or higher

P2125:
Either of following conditions met:	1 or 2
1. All of following conditions met:	(a) and (b)
(a) VPA2 voltage	1.2 V or less
(b) VPA voltage - Learned VPA accelerator off position voltage	0.04 V or higher
2. VPA2 voltage when VPA voltage 0.4 to 3.45 V	4.8 V or higher

P2127:
All of following conditions met:	(a) and (b)
(a) VPA2 voltage	1.2 V or less
(b) VPA voltage - Learned VPA accelerator off position voltage	0.04 V or higher

P2128:
VPA2 voltage when VPA 0.4 to 3.45 V	4.8 V or higher

P2138:
Either of following conditions A or B met:	-
Condition A	-
Difference between VPA and VPA 2 voltages	0.02 V or less
Condition B	-
VPA voltage	0.4 V or less
VPA2 voltage	1.2 V or less

COMPONENT OPERATING RANGE

VPA voltage	0.5 V to 4.5 V
VPA2 voltage	1.2 V to 4.7 V
Difference between VPA and VPA2 voltages	Higher than 0.05 V

CONFIRMATION DRIVING PATTERN

Connect the Techstream to the DLC3.
Turn the ignition switch to ON and turn the Techstream on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the ignition switch off and wait for at least 30 seconds.
Turn the ignition switch to ON and turn the Techstream on [A].
Fully depress and release the accelerator pedal [B].
Check that 5 seconds or more have elapsed since the ignition switch was turned to ON.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes [C].
Read pending DTCs.
HINT:
1. If a pending DTC is output, the system is malfunctioning.
2. If a pending DTC is not output, perform the following procedure.
Enter the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
Input the DTC: P2120, P2122, P2123, P2125, P2127, P2128 or P2138.

Check the DTC judgment result.

Techstream Display	Description
NORMAL	DTC judgment completed System normal
ABNORMAL	DTC judgment completed System abnormal
INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

HINT:

If the judgment result shows NORMAL, the system is normal.
If the judgment result shows ABNORMAL, the system has a malfunction.
If the judgment result shows INCOMPLETE or N/A, perform steps [B] through [C] again.

If no pending DTC is output, perform a universal trip and check for permanent DTCs (YARIS_NCP93 RM000000PDK0QGX.html).
HINT:
1. If a permanent DTC is output, the system is malfunctioning.
2. If no permanent DTC is output, the system is normal.

FAIL-SAFE

When any of DTCs P2120, P2121, P2122, P2123, P2125, P2127, P2128 and P2138 are stored, the ECM enters fail-safe mode. If either of the 2 sensor circuit malfunctions, the ECM uses the remaining circuit to calculate the accelerator pedal position to allow the vehicle to continue driving. 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 to OFF.

WIRING DIAGRAM

INSPECTION PROCEDURE

HINT:

Read freeze frame data using the Techstream. 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 TECHSTREAM (ACCEL SENSOR OUT NO. 1 AND NO. 2)

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream 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 Techstream.

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 4.7 V	More than 0.02 V

Text in Illustration
*a	Depressed
*b	Released

Go to step 2

CHECK FOR INTERMITTENT PROBLEMS (YARIS_NCP93 RM000000PDQ0NOX.html)

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

Disconnect the accelerator pedal 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
A20-6 (VPA) - A21-55 (VPA)	Always	Below 1 Ω
A20-5 (EPA) - A21-59 (EPA)
A20-4 (VCPA) - A21-57 (VCPA)
A20-3 (VPA2) - A21-56 (VPA2)
A20-2 (EPA2) - A21-60 (EPA2)
A20-1 (VCP2) - A21-58 (VCP2)

Standard Resistance (Check for Short):

Tester Connection	Condition	Specified Condition
A20-6 (VPA) or A21-55 (VPA) - body ground	Always	10 kΩ or higher
A20-5 (EPA) or A21-59 (EPA) - body ground
A20-4 (VCPA) or A21-57 (VCPA) - body ground
A20-3 (VPA2) or A21-56 (VPA2) - body ground
A20-2 (EPA2) or A21-60 (EPA2) - body ground
A20-1 (VCP2) or A21-58 (VCP2) - body ground

Reconnect the accelerator pedal assembly connector.

Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

3.INSPECT ECM (VCPA AND VCP2 VOLTAGE)

Disconnect the accelerator pedal assembly connector.

Turn the ignition switch to ON.

Measure the voltage between the terminals of the accelerator pedal assembly connector.
Standard Voltage:
Tester Connection
Switch Condition
Specified Condition
A20-4 (VCPA) - A20-5 (EPA)
Ignition switch ON
4.5 to 5.5 V
A20-1 (VCP2) - A20-2 (EPA2)
Text in Illustration
*a
Front view of wire harness connector
(to ECM)

Text in Illustration
*a	Front view of wire harness connector (to ECM)

Reconnect the accelerator pedal assembly connector.

REPLACE ECM (YARIS_NCP93 RM000001CN002AX.html)

OK

4.REPLACE ACCELERATOR PEDAL ASSEMBLY

Replace the accelerator pedal assembly (YARIS_NCP93 RM000001CYE01DX.html).

NEXT

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

Connect the Techstream to the DLC3.

Turn the ignition switch to ON.

Turn the Techstream on.

Clear DTCs (YARIS_NCP93 RM000000PDK0QGX.html).

Turn the ignition switch off and wait for at least 30 seconds.

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

Drive the vehicle in accordance with the driving pattern described in the Confirmation Driving Pattern.

Read DTCs.
Result
Result
Proceed to
P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 are output
A
DTC is not output
B

Result
Result	Proceed to
P2120, P2122, P2123, P2125, P2127, P2128, and/or P2138 are output	A
DTC is not output	B

END

REPLACE ECM (YARIS_NCP93 RM000001CN002AX.html)

Tester Connection	Switch Condition	Specified Condition
A20-4 (VCPA) - A20-5 (EPA)	Ignition switch ON	4.5 to 5.5 V
A20-1 (VCP2) - A20-2 (EPA2)	Ignition switch ON	4.5 to 5.5 V