SFI SYSTEM (w/ Electronic Throttle Control System), Diagnostic DTC:P0121, P0221

DTC Code DTC Name
P0121 Throttle / Pedal Position Sensor / Switch "A" Circuit Range / Performance Problem
P0221 Throttle / Pedal Position Sensor / Switch "B" Circuit Range / Performance Problem

DESCRIPTION

Tech Tips

This ETC (Electrical Throttle Control System) does not use a throttle cable.

The Throttle Position (TP) sensor is mounted on the throttle body assembly, and detects the opening angle of the throttle valve.

The TP sensor has two sensor circuits which each transmits a signal, VTA1 and VTA2. VTA1 is used to detect the throttle valve angle and VTA2 is used to detect malfunctions in VTA1. The sensor signal voltages vary between 0 V and 5 V. The VTA1 sensor signal voltage vary in proportion to the throttle valve opening angle, and are transmitted to the VTA terminals of the ECM.

As the valve closes, the VTA1 sensor output voltage decreases and as the valve opens, the VTA1 sensor output voltage increases. The ECM calculates the throttle valve opening angle according to these signals and controls the throttle actuator in response to driver inputs.

A013815E01
DTC No. DTC Detection Condition Trouble Area
P0121

  • A temporary malfunction is detected if the difference in output between sensors 1 and 2 is 6.3% or more. Following this temporary detection, if there is a 9% or more difference between sensor 1 and assumed throttle angle with MAP sensor, a malfunction is detected (1 trip detection logic).

  • ETCS throttle opener position error

  • Throttle Position (TP) sensor (built into throttle body assembly)

  • ECM
P0221

  • A temporary malfunction is detected if the difference in output between sensors 1 and 2 is 6.3 % or more. Following this temporary detection, if there is a 9 % or more difference between sensor 2 and assumed throttle angle with MAP sensor, a malfunction is detected (1 trip detection logic).

  • TP sensor (built into throttle body assembly)

  • ECM

Tech Tips

DTC P0121 and P0221 are detected when the vehicle is driven in the city at 30 to 50 km/h (19 to 31 mph) for 5 minutes.

WIRING DIAGRAM

A0137P5E02

INSPECTION PROCEDURE

Note

After replacing the ECM, perform electronic throttle learning Click here.

Tech Tips

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 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.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (THROTTLE BODY ASSEMBLY - ECM)


    1. A0138FJE01

      Disconnect the throttle body assembly connector.

    2. Disconnect the ECM connector.

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

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      B28-3 (VC) - B25-57 (VC) Always Below 1 Ω
      B28-6 (VTA) - B25-14 (VTA1) Always Below 1 Ω
      B28-5 (VTA2) - B25-15 (VTA2) Always Below 1 Ω
      B28-2 (E2) - B25-35 (ETA) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      B28-3 (VC) or B25-57 (VC) - Body ground Always 10 kΩ or higher
      B28-6 (VTA) or B25-14 (VTA1) - Body ground Always 10 kΩ or higher
      B28-5 (VTA2) or B25-15 (VTA2) - Body ground Always 10 kΩ or higher
      B28-2 (E2) or B25-35 (ETA) - Body ground Always 10 kΩ or higher
      B28-6 (VTA) or B25-14 (VTA1) - B28-3 (VC) or B25-57 (VC) Always 10 kΩ or higher
      B28-5 (VTA2) or B25-15 (VTA2) - B28-3 (VC) or B25-57 (VC) Always 10 kΩ or higher

    4. Reconnect the throttle body assembly connector.

    5. Reconnect the ECM connector.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. REPLACE THROTTLE BODY ASSEMBLY


    1. Replace the throttle body assembly Click here.

    2. Perform electronic throttle learning Click here.


    NEXT

    END