ECD SYSTEM(w/ DPF), Diagnostic DTC:P2122, P2123, P2127, P2128

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

DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal sensor assembly and detects the opening angle of the accelerator pedal. Since this sensor is electronically controlled with Hall-effect elements, accurate control and reliability can be obtained. It has 2 sensors to detect the accelerator position and malfunctions of the accelerator pedal sensor assembly.

In the accelerator pedal sensor assembly, the voltage applied to pedal terminals VPA and VPA2 of the ECM changes between 0 V and 5 V in proportion to the opening angle of the accelerator pedal. The VPA is a signal which indicates the actual accelerator pedal opening angle and is used for engine control, and the VPA2 is a signal which indicates the information about the opening angle and is used for detecting malfunctions. The ECM judges the current opening angle of the accelerator pedal using signals from terminals VPA and VPA2, and the ECM controls the injection volume based on these signals.

P2122
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Ignition switch is ON	VPA is less than 0.2 V for 0.5 seconds or more when accelerator pedal is depressed. (1 trip detection logic)	Open or short in accelerator pedal sensor assembly circuit Accelerator pedal sensor assembly ECM

P2123
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Ignition switch is ON	VPA is higher than 4.8 V for 0.5 seconds or more. (1 trip detection logic)	Open or short in accelerator pedal sensor assembly circuit Accelerator pedal sensor assembly ECM

P2127
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Ignition switch is ON	VPA2 is less than 0.5 V for 0.5 seconds or more when accelerator pedal is depressed. (1 trip detection logic)	Open or short in accelerator pedal sensor assembly circuit Accelerator pedal sensor assembly ECM

P2128
DTC Detection Drive Pattern	DTC Detection Condition	Trouble Area
Ignition switch is ON	VPA2 is higher than 4.8 V for 0.5 seconds or more. (1 trip detection logic)	Open or short in accelerator pedal sensor assembly circuit Accelerator pedal sensor assembly ECM

Related Data List
DTC No.	Data List
P2122 P2123 P2127 P2128	Accel Position Accel Sens. No. 1 Volt % Accel Sens. No. 2 Volt %

Tech Tips

When DTC P2122, P2123, P2127 and/or P2128 is stored, as a fail-safe operation the ECM limits engine power, such as by estimating the accelerator pedal position as 0%.
When DTC P2122, P2123, P2127 and/or P2128 is stored, check the accelerator pedal sensor assembly output by entering the following menus on the GTS: Powertrain / Engine and ECT / Data List / Accel Position.

Reference
Accelerator Pedal Position (Fully Closed)	Accelerator Pedal Position (Fully Open)	Trouble Area
0%	0%	Open in VCPA or VCP2 circuit Open or short in VPA or VPA2 circuit
Approximately 100%	Approximately 100%	Open in EPA or EPA2 circuit

WIRING DIAGRAM


*a	Accelerator Pedal Sensor Assembly

CAUTION / NOTICE / HINT

Note

When replacing the ECM, the ECM needs Registration and Initialization Click here.

Tech Tips

When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the GTS. Then after installing the new ECM, perform all of the initialization/registrations for the "Learning Values Write" function by following the instructions shown on the GTS display.
Read freeze frame data using the GTS. 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, and other data from the time the malfunction occurred.

PROCEDURE

READ VALUE USING GTS (ACCEL SENS. NO.1 VOLT % AND ACCEL SENS. NO.2 VOLT %)

Text in Illustration
*1	Accelerator Pedal
*a	Depressed
*b	Released

Connect the GTS to the DLC3.

Turn the ignition switch to ON.
Turn the GTS on.
Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sens. No.1 Volt % and Accel Sens. No.2 Volt %.

Read the value when depressing and releasing the accelerator pedal.

Standard Voltage

GTS Display	Condition	Specified Condition
Accel Sens. No.1 Volt %	Depressed	52 to 90%
Accel Sens. No.1 Volt %	Released	10 to 22%
Accel Sens. No.2 Volt %	Depressed	68 to 99%
Accel Sens. No.2 Volt %	Released	24 to 40%

CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here

CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL SENSOR ASSEMBLY - ECM)

Disconnect the A36 accelerator pedal sensor assembly connector.
Disconnect the A108 ECM connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
A36-4 (VCPA) or A108-27 (VCPA) - Body ground	Always	10 kΩ or higher
A36-6 (VPA) or A108-42 (VPA) - Body ground	Always	10 kΩ or higher
A36-5 (EPA) or A108-22 (EPA) - Body ground	Always	10 kΩ or higher
A36-1 (VCP2) or A108-28 (VCP2) - Body ground	Always	10 kΩ or higher
A36-3 (VPA2) or A108-43 (VPA2) - Body ground	Always	10 kΩ or higher
A36-2 (EPA2) or A108-23 (EPA2) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR Click here

CHECK TERMINAL VOLTAGE (VC VOLTAGE)

Text in Illustration

*a
Front view of wire harness connector

(to Accelerator Pedal Sensor Assembly)

Disconnect the accelerator pedal sensor assembly connector.
Turn the ignition switch to ON.

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

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

Standard Voltage

Tester Connection	Switch Condition	Specified Condition
A36-4 (VCPA) - A36-5 (EPA)	Ignition switch ON	4.5 to 5.5 V
A36-1 (VCP2) - A36-2 (EPA2)	Ignition switch ON	4.5 to 5.5 V

REPLACE ECM Click here

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

CHECK WHETHER DTC OUTPUT RECURS

Connect the GTS to the DLC3.
Turn the ignition switch to ON.
Turn the GTS on.
Clear the DTCs Click here.
Turn the ignition switch off and wait for 30 seconds or more.
Turn the ignition switch to ON.
Fully close the accelerator pedal for 3 seconds, then hold it partway open for 3 seconds, and then fully open it for 3 seconds.
Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

Read the DTCs.

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

END

REPLACE ECM
1. Replace the ECM Click here.
NEXT
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Click here
REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT
CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED
1. Connect the GTS to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the GTS on.
4. Clear the DTCs Click here.
5. Turn the ignition switch off and wait for 30 seconds or more.
6. Turn the ignition switch to ON.
7. Fully close the accelerator pedal for 3 seconds, then hold it partway open for 3 seconds, and then fully open it for 3 seconds.
8. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
9. Confirm that the DTC is not output again.
NEXT
END