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Home >> Scion >> 2004 >> xA Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnosis >> DTC P0120, DTC P0122, DTC P0123: Throttle/Pedal Position Sensor/Switch "A" Circuit >> Inspection Procedure

Inspection Procedure

NOTE:
  • If different DTCs related to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may be open.
  • Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.
  1. READ VALUE OF HAND-HELD TESTER (THROTTLE VALVE OPENING PERCENTAGE) 
    1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
    2. Turn the ignition switch ON.
    3. Select the item "DIAGNOSIS / ENHANCED OBD II / DATA LIST / ETCS / THROTTLE POS" and read its value displayed on the hand-held tester OBD II scan tool.
      Fig 1: Identifying Accelerator Pedal Position
      G03367046Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result: 

      RESULT

      Accelerator Pedal Operation Throttle Valve Opening Position Expressed As Percentage Proceed To
      Released --> Depressed 0 % A
      Approx. 10 % --> 70 % B
      Approx. 100 % C
    1. B : CHECK FOR INTERMITTENT PROBLEMS (See  CHECK FOR INTERMITTENT PROBLEMS  ) 
    2. C : Go to step   4 . 
    3. A : Go to next step. 
  2. INSPECT THROTTLE POSITION SENSOR 
    1. Disconnect the T1 throttle position sensor connector.
    2. Measure the resistance between the terminals of the throttle position sensor.

      Standard: 

      STANDARD

      Tester Connection Throttle Valve Specified Condition
      VC (T1-1) - E2 (T1-2) - 2.5 to 5.9 kΩ
      VTA (T1 3) E2 (T1 2) Fully closed 0.2 to 5.7 kΩ
      Fully Open 2.0 to 10.2 kΩ
    3. Reconnect the throttle position sensor connector.
      Fig 2: Identifying T1 Throttle Position Sensor Connector
      G03367047Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG : REPLACE THROTTLE POSITION SENSOR 
    2. OK : Go to next step. 
  3. CHECK HARNESS AND CONNECTOR (ECM - THROTTLE POSITION SENSOR) 
    1. Reconnect the T1 throttle position sensor connector.
    2. Disconnect the E3 ECM connector.
    3. Measure the resistance between the terminals of the E3 ECM connector.

      Standard: 

      STANDARD

      Tester Connection Throttle Valve Specified Condition
      VC (E3-18) - E2 (E3-28) - 2.5 to 5.9 kΩ
      VTA(E3-21) - E2 (E3-28) Fully Closed 0.2 to 5.7 kΩ
      Fully Open 2.0 to 10.2 kΩ
    4. Measure the resistance between the terminals of the E3 ECM connector.
      Fig 3: Identifying E3 ECM Connector
      G03367048Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard (Check for short): 

      STANDARD (CHECK FOR SHORT)

      Tester Connection Specified Condition
      VC (E3-18) - Body Ground 10 kΩ Or Higher
      VTA (E3-28) - Body Ground
    5. Reconnect the ECM connector.
    1. NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK : REPLACE ECM (See  REPLACEMENT  ) 
  4. INSPECT THROTTLE POSITION SENSOR 
    1. Disconnect the T1 throttle position sensor connector.
    2. Measure the resistance between the terminals of the throttle position sensor.

      Standard: 

      STANDARD

      Tester Connection Throttle Valve Specified Condition
      VC (T1-1) - E2 (T1-2) - 2.5 to 5.9 kΩ
      VTA (T1 3) E2 (T1 2) Fully Closed 0.2 to 5.7 kΩ
      Fully Open 2.0 to 10.2 kΩ
    3. Reconnect the throttle position sensor connector.
      Fig 4: Identifying T1 Throttle Position Sensor Connector
      G03367049Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. NG : REPLACE THROTTLE POSITION SENSOR 
    2. OK : Go to next step. 
  5. CHECK HARNESS AND CONNECTOR (ECM - THROTTLE POSITION SENSOR) 
    1. Disconnect the E3 ECM connector.
      2. Fig 5: Identifying E3 ECM Connector
      G03367050Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the T1 throttle position sensor connector.
      3. Fig 6: Identifying T1 Throttle Position Sensor Connector
      G03367051Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance between the wire harness side connectors.

      Standard (Check for open): 

      STANDARD (CHECK FOR OPEN)

      Tester Connection Specified Condition
      E2 (T1-2) - E2 (E3-28) Below 1 Ω
    4. Reconnect the throttle position sensor connector.
    5. Reconnect the ECM connector.
    1. NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK : REPLACE ECM (See  REPLACEMENT  ) 
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