Sfi System - P2121

Brand:

Toyota

Model Name:

4Runner GRN210 215 UZN210 215

Manual:

Repair Manual

Section:

2Uz-Fe Engine Control System

Title:

Sfi System

  1. Description

  2. Monitor description

  3. Monitor strategy

  4. Typical enabling conditions

  5. Typical malfunction thresholds

  6. Fail-safe

  7. Wiring diagram

  8. Inspection procedure

  9. Check any other dtcs output (in addition to dtc p2121)

  10. Read value of intelligent tester (accel pos#1 and accel pos#2)

  11. Replace accelerator pedal assembly

  12. Check whether dtc output recurs (dtc p2121)

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


​

DESCRIPTION

HINT:
This DTC relates to the Accelerator Pedal Position (APP) sensor.
Refer to DTC P2120 (Click here).

DTC No.
DTC Detection Condition
Trouble Area
P2121
Conditions (a) and (b) continue for 0.5 second:
(a) Difference between VPA1 and VPA2 deviates from the standard
(b) IDL is OFF
  1. APP sensor
  2. ECM

MONITOR DESCRIPTION

The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal position sensor has 2 sensor elements / signal outputs: VPA1 and VPA2. VPA1 is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA1. When the difference between the voltage outputs of VPA1 and VPA2 deviates from the standard, the ECM concludes the accelerator pedal position sensor has a malfunction. The ECM turns on the MIL and a DTC is set.

MONITOR STRATEGY


Related DTCs
P2121: Accelerator pedal position (APP) sensor rationality
Required Sensors/Components (Main)
APP sensor
Required Sensors/Components (Related)
-
Frequency of Operation
Continuous
Duration
0.5 seconds
MIL Operation
Immediate
Sequence of Operation
None

TYPICAL ENABLING CONDITIONS


Monitor runs whenever following DTCs not present
None
Either of the following conditions is met:
Condition 1 or 2
1. Ignition switch
ON
2. Throttle actuator power
ON

TYPICAL MALFUNCTION THRESHOLDS


Difference between VPA1 voltage (learned value) and VPA2 voltage (learned value)
Less than 0.4 V, or more than 1.2 V

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 remaining circuit is used to calculate the accelerator pedal opening to allow the vehicle to continue driving.
If both circuits malfunction, the ECM regards the opening angle of the accelerator pedal to be fully closed. In this case, the throttle valve will remain closed as if the engine is idling.
If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

WIRING DIAGRAM

Refer to DTC P2120 (Click here).

INSPECTION PROCEDURE

HINT:
Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
1.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2121)

  1. Connect the intelligent tester to the DLC3 with CAN VIM.

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

  1. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

  1. Read DTCs.

    Result:

    Display (DTC Output)
    		Proceed to
    P2121
    		A
    P2121 and other DTCs
    		B
    HINT:
    If any DTCs other than P2121 are output, troubleshoot those DTCs first.


Bnext
GO TO DTC CHART
A
next down

2.READ VALUE OF INTELLIGENT TESTER (ACCEL POS#1 AND ACCEL POS#2)
  1. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3. 4Runner

  2. Connect the intelligent tester to the CAN VIM. Then connect the CAN VIM to the DLC3.

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

  1. Enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ETCS / ACCEL POS#1 and ACCEL POS#2.

  1. Read the voltage for the accelerator pedal position sensor data.

    Standard voltage:
    Accelerator pedal operations
    		ACCEL POS#1
    		ACCEL POS#2
    Released
    		0.5 to 1.1 V
    		1.5 to 2.9 V
    Depressed
    		2.5 to 4.6 V
    		3.5 to 5.5 V


OKnext
CHECK FOR INTERMITTENT PROBLEMS
NG
next down

3.REPLACE ACCELERATOR PEDAL ASSEMBLY

NEXT
next down

4.CHECK WHETHER DTC OUTPUT RECURS (DTC P2121)

  1. Connect the intelligent tester to the DLC3 with CAN VIM.

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

  1. Clear DTCs (Click here).

  1. Allow the engine to idle for 15 seconds.

  1. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

  1. Read DTCs.

    Result:

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


Bnext
CHECK FOR INTERMITTENT PROBLEMS
A
next down
REPLACE ECM