DTC    P1120    Accelerator Pedal Position Sensor Circuit Malfunction

for Preparation Click here


DESCRIPTION

The Accelerator Pedal Position (APP) sensor is mounted on the accelerator pedal 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 position sensor.
In the accelerator pedal position sensor, 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.

A112620E81


P1120 
DTC Detection Drive Pattern
DTC Detection Condition
Trouble Area
Ignition switch is ON
  1. Condition (a) or (b) continues for 0.5 seconds or more:
    (1 trip detection logic)
    1. VPA is less than 0.2 V when accelerator pedal is fully released, or VPA is more than 4.8 V
    2. VPA2 is less than 0.5 V when accelerator pedal is fully released, or VPA2 is more than 4.8 V
  1. Open or short in accelerator pedal position sensor circuit
  2. Accelerator pedal position sensor
  3. ECM

Related Data List 
DTC No.
Data List
P1120
  1. Accel Position
  2. Accel Sens. No. 1 Volt %
  3. Accel Sens. No. 2 Volt %
  4. Accel Sensor Out No.1
  5. Accel Sensor Out No.2

HINT:
  1. When DTC P1120 is stored, as a fail-safe operation the ECM limits engine power, such as by estimating the accelerator pedal position as 0 %.
  2. When DTC P1120 is stored, check the accelerator pedal position sensor output by entering the following menus on the intelligent tester: Powertrain / Engine and ECT / Data List / Accel Position.


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

WIRING DIAGRAM


A198997E01


INSPECTION PROCEDURE

NOTICE:
When replacing the ECM, the ECM needs Registration and Initialization (Click here).

HINT:
  1. When the ECM must be replaced, before replacing the ECM, perform the "Learning Values Save" function using the intelligent tester. Then after installing the new ECM, perform all of the initializations/registrations for the "Learning Values Write" function by following the instructions shown on the tester display.
  2. 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, and other data from the time the malfunction occurred.

1.READ VALUE USING INTELLIGENT TESTER (ACCELERATOR PEDAL POSITION)


    C129061E02

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON and turn the tester on.

  1. Enter the following menus: Powertrain / Engine and ECT / Data List / Accel Sensor Out No.1 and Accel Sensor Out No.2.

  1. Read the value when depressing and releasing the accelerator pedal.

    Standard Voltage:

    Tester Display
    		Condition
    		Specified Condition
    (Medium Value)
    Accel Sensor Out No.1
    		Depressed
    		Less than 4.6 V
    (3.2 V)
    Released
    		More than 0.4 V
    (0.7 V)
    Accel Sensor Out No.2
    		Depressed
    		Less than 4.6 V
    (4.0 V)
    Released
    		More than 0.4 V
    (1.5 V)



OK
Go to step 8

NG
Go to step 2

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


    A200290E01

  1. Disconnect the accelerator pedal position sensor connector.

  1. Disconnect the ECM connector.

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

    Standard Resistance (Check for Open):
    Tester Connection
    		Condition
    		Specified Condition
    A33-1 (VCP2) - A19-53 (VCP2)
    		Always
    		Below 1 Ω
    A33-2 (EPA2) - A19-54 (EPA2)
    		Always
    		Below 1 Ω
    A33-3 (VPA2) - A19-52 (VPA2)
    		Always
    		Below 1 Ω
    A33-4 (VCPA) - A19-56 (VCPA)
    		Always
    		Below 1 Ω
    A33-5 (EPA) - A19-57 (EPA)
    		Always
    		Below 1 Ω
    A33-6 (VPA) - A19-55 (VPA)
    		Always
    		Below 1 Ω

    Standard Resistance (Check for Short):
    Tester Connection
    		Condition
    		Specified Condition
    A33-1 (VCP2) or A19-53 (VCP2) - Body ground
    		Always
    		10 kΩ or higher
    A33-2 (EPA2) or A19-54 (EPA2) - Body ground
    		Always
    		10 kΩ or higher
    A33-3 (VPA2) or A19-52 (VPA2) - Body ground
    		Always
    		10 kΩ or higher
    A33-4 (VCPA) or A19-56 (VCPA) - Body ground
    		Always
    		10 kΩ or higher
    A33-5 (EPA) or A19-57 (EPA) - Body ground
    		Always
    		10 kΩ or higher
    A33-6 (VPA) or A19-55 (VPA) - Body ground
    		Always
    		10 kΩ or higher

    Text in Illustration 
    *1
    		Front view of wire harness connector
    (to Accelerator Pedal Position Sensor)
    *2
    		Front view of wire harness connector
    (to ECM)

  1. Reconnect the accelerator pedal position sensor connector.

  1. Reconnect the ECM connector.



NG
Go to step 7
OK


3.INSPECT ECM TERMINAL VOLTAGE (VCPA AND VCP2 TERMINALS)


    A200311E02

  1. Disconnect the accelerator pedal position sensor connector.

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

    Standard Voltage:
    Tester Connection
    		Switch Condition
    		Specified Condition
    A33-4 (VCPA) - A33-5 (EPA)
    		Ignition switch ON
    		4.5 to 5.5 V
    A33-1 (VCP2) - A33-2 (EPA2)
    		Ignition switch ON
    		4.5 to 5.5 V

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

  1. Reconnect the accelerator pedal position sensor connector.



NG
Go to step 6
OK


4.REPLACE ACCELERATOR PEDAL SENSOR ASSEMBLY

  1. Replace the accelerator pedal sensor assembly (Click here).


NEXT


5.CHECK WHETHER DTC OUTPUT RECURS

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (Click here).

  1. Turn the ignition switch off and wait for 30 seconds or more.

  1. Turn the ignition switch to ON.

  1. Fully close the accelerator pedal for 3 seconds, and then hold it partway open for 3 seconds, then fully open it for 3 seconds.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Read the DTCs.
    Result 
    Result
    		Proceed to
    DTC P1120
    		A
    No DTC output
    		B



B
END
A


6.REPLACE ECM

  1. Replace the ECM (Click here).



NEXT
Go to step 8

7.REPAIR OR REPLACE HARNESS OR CONNECTOR

NEXT


8.CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED

  1. Connect the intelligent tester to the DLC3.

  1. Clear the DTCs (Click here).

  1. Turn the ignition switch off and wait for 30 seconds or more.

  1. Turn the ignition switch to ON.

  1. Fully close the accelerator pedal for 3 seconds, and then hold it partway open for 3 seconds, then fully open it for 3 seconds.

  1. Enter the following menus: Powertrain / Engine and ECT / DTC.

  1. Confirm that the DTC is not output again.


NEXT

END