Dtc P2121 Throttle / Pedal Position Sensor / Switch D Circuit Range / Performance

Engine. Lexus Gs430, Gs300. Uzs190 Grs190
3Gr-Fe Engine Control System. Lexus Gs430, Gs300. Uzs190 Grs190

DESCRIPTION

MONITOR DESCRIPTION

FAIL-SAFE

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING INTELLIGENT TESTER (ACCELERATOR POSITION NO. 1 AND ACCELERATOR POSITION NO. 2)

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

REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

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

DTC P2121 Throttle / Pedal Position Sensor / Switch "D" Circuit Range / Performance


DESCRIPTION


HINT:
Refer to DTC P2120 on page Click here.

DTC No.
DTC Detection Condition
Trouble Area
P2121
Difference between VPA and VPA2 less than 0.4 V, or more than 1.2 V for 0.5 seconds (1 trip detection logic)
  1. Accelerator pedal position sensor
  1. ECM

MONITOR DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal basket. The accelerator pedal position sensor has 2 sensor elements and 2 signal outputs: VPA and VPA2. VPA is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA. When the difference between the output voltages of VPA and VPA2 deviates from the standard, the ECM determines that the accelerator pedal position sensor is a malfunctioning. The ECM turns on the MIL and the DTC is set.

FAIL-SAFE

The accelerator pedal position sensor has two (main and sub) sensor circuits. If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between the two sensor circuits and switches to limp mode. In limp mode, the functioning circuit is used to calculate the accelerator pedal opening angle to allow the vehicle to continue driving. If both circuits malfunction, the ECM regards the opening angle of the accelerator pedal as being fully closed. In this case, the throttle valve remains closed as if the engine is idling.
If a pass condition is detected and then the engine switch is turned to off, the fail-safe operation stops and the system returns to a normal condition.

WIRING DIAGRAM

Refer to DTC P2120 on page Click here.

INSPECTION PROCEDURE

HINT:
  1. Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions 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.
  1. This DTC relates to the Accelerator Pedal Position (APP) sensor.
1.READ VALUE USING INTELLIGENT TESTER (ACCELERATOR POSITION NO. 1 AND ACCELERATOR POSITION NO. 2)
Lexus Gs430, Gs300. Uzs190 Grs190.3Gr-Fe Engine Control System.Sfi System. Dtc P2121 Throttle / Pedal Position Sensor / Switch D Circuit Range / Performance

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the tester ON.

  1. Enter the following menus: Powertrain / Engine / Data List / Accelerator Position No. 1 and Accelerator Position No. 2.

  1. Read the values displayed on the tester.

    Standard voltage:
    Accelerator Pedal Operations
    		Accelerator Position No. 1
    		Accelerator Position 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


OK
Go to step 3
NG


2.CHECK HARNESS AND CONNECTOR (ACCELERATOR PEDAL POSITION SENSOR - ECM)
Lexus Gs430, Gs300. Uzs190 Grs190.3Gr-Fe Engine Control System.Sfi System. Dtc P2121 Throttle / Pedal Position Sensor / Switch D Circuit Range / Performance

  1. Disconnect the A36 Accelerator Pedal Position (APP) sensor connector.

  1. Disconnect the A7 ECM connector.

  1. Measure the resistance.

    Standard resistance (Check for open):
    Tester Connection
    		Specified Condition
    VPA (A36-6) - VPA (A7-33)
    		Below 1 Ω
    EPA (A36-5) - EPA (A7-34)
    		Below 1 Ω
    VCPA (A36-4) - VCPA (A7-35)
    		Below 1 Ω
    VPA2 (A36-3) - VPA2 (A7-32)
    		Below 1 Ω
    EPA2 (A36-2) - EPA2 (A7-26)
    		Below 1 Ω
    VCP2 (A36-1) - VCP2 (A7-27)
    		Below 1 Ω
    Standard resistance (Check for short):
    Tester Connection
    		Specified Condition
    VPA (A36-6) or VPA (A7-33) - body ground
    		10 kΩ or higher
    EPA (A36-5) or EPA (A7-34) - body ground
    		10 kΩ or higher
    VCPA (A36-4) or VCPA (A7-35) - body ground
    		10 kΩ or higher
    VPA2 (A36-3) or VPA2 (A7-32) - body ground
    		10 kΩ or higher
    EPA2 (A36-2) or EPA2 (A7-26) - body ground
    		10 kΩ or higher
    VCP2 (A36-1) or VCP2 (A7-27) - body ground
    		10 kΩ or higher

  1. Reconnect the APP sensor connector.

  1. Reconnect the ECM connector.



NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


3.REPLACE ACCELERATOR PEDAL ROD ASSEMBLY

NEXT


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

  1. Connect the intelligent tester to the DLC3.

  1. Turn the engine switch on (IG) and turn the tester ON.

  1. Clear DTCs (Click here).

  1. Start the engine.

  1. Allow the engine to idle for 15 seconds.

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

  1. Read DTCs.

    Result:

    Display (DTC Output)
    		Proceed to
    P2121
    		A
    No output
    		B


B
SYSTEM OK
A

REPLACE ECM