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Home >> Scion >> 2004 >> xA Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Diagnosis >> DTC P0451, DTC P0452, DTC P0453: Evaporative Emission Control System Pressure Sensor/Switch >> 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.
  • If DTC P0441 (Purge Flow), P0446 (VSV for CCV), P0451, P0452 or P0453 (Evaporative Pressure Sensor) is output with DTC P0442 or P0456, troubleshoot DTC P0441, P0446, P0451, P0452 or P0453 first. If no malfunction is detected, troubleshoot DTC P0442 or P0456 next.
  • 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.
  • If the ENGINE RUN TIME in the freeze frame data is less than 200 seconds, carefully check the vapor pressure sensor.
  1. INSPECT ECM (VC VOLTAGE) 
    Fig 1: Inspecting ECM (VC Voltage)
    G03367182Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch ON.
    2. Measure the voltage between the specified terminals of the E3 ECM connector.

      Standard: 

      STANDARD

      Tester Connection Specified Condition
      VC (E3-18) - E2 (E3-28) 4.5 to 5.5 V
    1. NG : REPLACE ECM (See  REPLACEMENT  ) 
    2. OK : Go to next step. 
  2. INSPECT ECM (PTNK VOLTAGE) 
    Fig 2: Inspecting ECM (PTNK Voltage)
    G03367183Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    1. Turn the ignition switch ON.
    2. Measure the voltage between the specified terminals of the E3 and E6 ECM connectors.
      1. Remove the vapor pressure sensor.

        Standard (1): 

        STANDARD

        Tester Connection Specified Condition
        PTNK (E6-21) - E2 (E3-28) 2.9 to 3.7 V
      2. Using the MITYVAC (Hand-Held Vacuum Pump), apply a vacuum of 4.0 kPa (30 mmHg, 1.18 in.Hg) to the vapor pressure sensor.
        NOTE: The vacuum applied to the vapor pressure sensor must be less than 66.7 kPa (500 mmHg, 19.7 in.Hg).

        Standard (2): 

        STANDARD

        Tester Connection Specified Condition
        PTNK (E6-21) - E2 (E3-28) 0.5 V or less
      3. Reinstall the vapor pressure sensor.
    1. OK : REPLACE ECM (See  REPLACEMENT  ) 
    2. NG : Go to next step. 
  3. CHECK HARNESS AND CONNECTOR (VAPOR PRESSURE SENSOR - ECM) 
    1. Disconnect the V3 vapor pressure sensor connector.
      2. Fig 3: Disconnecting V3 Vapor Pressure Sensor Connector
      G03367184Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the E3 and E6 ECM connectors.
      3. Fig 4: Identifying E3 & E6 ECM Connectors
      G03367185Courtesy 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
      PTNK (V3-2) - PTNK (E6-21) Below 1 Ω
      GND (V3-1) - E2 (E3-28)
      VCC (V3-3) - VC (E3-18)

      Standard (Check for short): 

      STANDARD (CHECK FOR SHORT)

      Tester Connection Specified Condition
      PTNK (V3-2) Or PTNK (E6-21) - Body Ground 10 kΩ Or Higher
      VCC (V3-3) Or VC (E3-18) - Body Ground
    4. Reconnect the vapor pressure sensor connector.
    5. Reconnect the ECM connector.
    1. NG : REPAIR OR REPLACE HARNESS OR CONNECTOR 
    2. OK : REPLACE VAPOR PRESSURE SENSOR ASSY 
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