SFI SYSTEM, Diagnostic DTC:P2120, P2122, P2123, P2125, P2127, P2128, P2138

DTC Code	DTC Name
P2120	Throttle / Pedal Position Sensor / Switch "D" Circuit
P2122	Throttle / Pedal Position Sensor / Switch "D" Circuit Low Input
P2123	Throttle / Pedal Position Sensor / Switch "D" Circuit High Input
P2125	Throttle / Pedal Position Sensor / Switch "E" Circuit
P2127	Throttle / Pedal Position Sensor / Switch "E" Circuit Low Input
P2128	Throttle / Pedal Position Sensor / Switch "E" Circuit High Input
P2138	Throttle / Pedal Position Sensor / Switch "D" / "E" Voltage Correlation

CAUTION / NOTICE / HINT

Tech Tips

These DTCs relate to the accelerator pedal position sensor.
This electronic throttle control system does not use a throttle cable.

DESCRIPTION

The accelerator pedal position 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. 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 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 position (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 accelerator pedal position sensor itself.

The ECM monitors the actual accelerator pedal position (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

DTC No.	DTC Detection Condition	Trouble Area
P2120	VPA fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1-trip detection logic).	Accelerator pedal assembly ECM
P2122	VPA is 0.4 V or less for 0.5 seconds or more when the accelerator pedal is fully released (1-trip detection logic).	Accelerator pedal assembly Open in VCPA circuit Open or ground short in VPA circuit ECM
P2123	VPA is 4.8 V or higher for 2.0 seconds or more (1-trip detection logic).	Accelerator pedal assembly Open in EPA circuit ECM
P2125	VPA2 fluctuates rapidly beyond the upper and lower malfunction thresholds for 0.5 seconds or more (1-trip detection logic).	Accelerator pedal assembly ECM
P2127	VPA2 is 1.2 V or less for 0.5 seconds or more when the accelerator pedal is fully released (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 is 4.8 V or higher. (b) VPA is 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) The difference between VPA and VPA2 is 0.02 V or less. (b) VPA is 0.4 V or less and VPA2 is 1.2 V or less.	Short between VPA and VPA2 circuits Accelerator pedal assembly ECM

Tech Tips

When any of these DTCs are output, check the accelerator pedal position sensor voltage using the intelligent tester. Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No.1 and Accel Sensor Out No.2.

Trouble Area	Accel Sensor Out No.1 When Accelerator Pedal Released	Accel Sensor Out No.2 When Accelerator Pedal Released	Accel Sensor Out No.1 When Accelerator Pedal Depressed	Accel Sensor Out No.2 When Accelerator Pedal Depressed
VCPA or VCP2 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 5.0 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 or EPA2 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 5.0 V

Tech Tips

Accelerator pedal positions are expressed as voltages.

FAIL-SAFE

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

WIRING DIAGRAM

INSPECTION PROCEDURE

Tech Tips

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 (ACCEL SENSOR OUT NO.1 AND ACCEL SENSOR OUT NO.2)

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 / Accel Sensor Out No.1 and Accel Sensor Out No.2.

Read the value displayed on the tester.

Standard Voltage

Accelerator Pedal Operation	Accel Sensor Out No.1	Accel Sensor Out No.2
Released	0.5 to 1.1 V	1.2 to 2.0 V
Depressed	2.6 to 4.5 V	3.4 to 5.0 V

CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL ASSEMBLY - ECM) Click here

CHECK FOR INTERMITTENT PROBLEMS Click here

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
A2-6 (VPA) - A40-55 (VPA)	Always	Below 1 Ω
A2-5 (EPA) - A40-59 (EPA)	Always	Below 1 Ω
A2-4 (VCPA) - A40-57 (VCPA)	Always	Below 1 Ω
A2-3 (VPA2) - A40-56 (VPA2)	Always	Below 1 Ω
A2-2 (EPA2) - A40-60 (EPA2)	Always	Below 1 Ω
A2-1 (VCP2) - A40-58 (VCP2)	Always	Below 1 Ω

Standard Resistance (Check for Short)

Tester Connection	Condition	Specified Condition
A2-6 (VPA) or A40-55 (VPA) - Body ground	Always	10 kΩ or higher
A2-5 (EPA) or A40-59 (EPA) - Body ground	Always	10 kΩ or higher
A2-4 (VCPA) or - A40-57 (VCPA) - Body ground	Always	10 kΩ or higher
A2-3 (VPA2) or A40-56 (VPA2) - Body ground	Always	10 kΩ or higher
A2-2 (EPA2) or A40-60 (EPA2) - Body ground	Always	10 kΩ or higher
A2-1 (VCP2) or A40-58 (VCP2) - Body ground	Always	10 kΩ or higher

Reconnect the accelerator pedal assembly connector.
Reconnect the ECM connector.

REPAIR OR REPLACE HARNESS OR CONNECTOR (ACCELERATOR PEDAL ASSEMBLY - ECM)

INSPECT ECM (VCPA AND VCP2 VOLTAGE)

Text in Illustration

*1
Front view of wire harness connector

(to Accelerator Pedal Assembly)

Disconnect the accelerator pedal assembly connector.

Text in Illustration
*1	Front view of wire harness connector (to Accelerator Pedal Assembly)

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
A2-4 (VCPA) - A2-5 (EPA)	Ignition switch ON	4.5 to 5.5 V
A2-1 (VCP2) - A2-2 (EPA2)	Ignition switch ON	4.5 to 5.5 V

Reconnect the accelerator pedal assembly connector.

REPLACE ECM Click here

REPLACE ACCELERATOR PEDAL ASSEMBLY
1. Replace the accelerator pedal assembly Click here.
NEXT

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

Connect the intelligent tester to the DLC3.
Turn the Ignition switch to ON.
Turn the tester on.
Clear the DTCs Click here.
Start the engine.
Allow the engine to idle for 15 seconds.
Enter the following menus: Powertrain / Engine and ECT / DTC.

Read the DTCs.

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

END

REPLACE ECM Click here