1Ur-Fe Engine Control. Dtc P2121 Throttle / Pedal Position Sensor / Switch D Circuit Range / Performance

1. Difference between VPA and VPA2 is less than 0.4 V, or more than 1.2 V. (learned value of accelerator off position)
2. Difference between VPA and VPA2 is greater than or equal to the specified value.

Accelerator pedal sensor assembly

MONITOR DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal bracket. 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 malfunctioning. The ECM turns on the MIL and stores the DTC.

CONFIRMATION DRIVING PATTERN

Land Cruiser. Urj200, 202 Grj200 Vdj200.1Ur-Fe Engine Control.Sfi System.
Dtc
P2121 Throttle / Pedal Position Sensor / Switch D Circuit Range / Performance

Connect the GTS to the DLC3.
Turn the engine switch on (IG) and turn the GTS on.
Clear DTCs (even if no DTCs are stored, perform the clear DTC operation).
Turn the engine switch off and wait for at least 30 seconds.
Turn the engine switch on (IG) and turn the GTS on [A].
Wait for 5 seconds after turning the engine switch to ON.
Operate the accelerator pedal in accordance with the following procedure [B].

Enter the following menus: Powertrain / Engine and ECT / Data List / Gas Throttle / Accel Sens. No.1 Volt %, and Accel Sens. No.2 Volt %.
Slowly depress the accelerator pedal until Accel Sens. No.1 Volt % is approximately 30% and Accel Sens. No.2 Volt % is approximately 46%, then slowly release the accelerator pedal.

Enter the following menus: Powertrain / Engine and ECT / Trouble codes [C].
Read the 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: P2121.

Check the DTC judgment result.

GTS 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.

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 position to allow the vehicle to continue driving. If both circuits malfunction, the ECM regards the accelerator pedal as being fully released. 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 off, the fail-safe operation stops and the system returns to normal.

WIRING DIAGRAM

Refer to DTC P2120 (Click here).

INSPECTION PROCEDURE

HINT:

This DTC relates to the accelerator pedal position sensor.
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, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

1.CHECK FOR ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2121)

Connect the GTS to the DLC3.

Turn the engine switch on (IG).

Turn the GTS on.

Enter the following menus: Powertrain / Engine and ECT / Trouble codes.

Read DTCs.

Result
Result
Proceed to
P2121 is output
A
P2121 and other DTCs are output
B
HINT:
If any DTCs other than P2121 are output, troubleshoot those DTCs first.

Result
Result	Proceed to
P2121 is output	A
P2121 and other DTCs are output	B

GO TO DTC CHART (Click here)

A

2.READ VALUE USING GTS (ACCELERATOR PEDAL POSITION SENSOR)

Connect the GTS to the DLC3.

Turn the engine switch on (IG).

Turn the GTS on.

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

Read the values displayed on the GTS.

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	0.4 to 1.2 V
Depressed	2.6 to 4.5 V	3.4 to 4.75 V	0.4 to 1.2 V

Text in Illustration
*a	Depressed
*b	Released

Go to step 3

CHECK FOR INTERMITTENT PROBLEMS (Click here)

3.REPLACE ACCELERATOR PEDAL POSITION SENSOR ASSEMBLY

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

NEXT

4.CHECK WHETHER DTC OUTPUT RECURS (DTC P2121)

Connect the GTS to the DLC3.

Turn the engine switch on (IG).

Turn the GTS on.

Clear DTCs (Click here).

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

Read DTCs.

Result
Result
Proceed to
P2121 is output
A
No DTC is output
B

Result
Result	Proceed to
P2121 is output	A
No DTC is output	B

END

REPLACE ECM (Click here)