LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2012 >> Prius Four >> Repair and Diagnosis (Single Page) >> Transmission >> Automatic Trans >> Electronic A/T Shift Lever System (Except Plug-In) (Diagnostic Codes & Circuit Tests) >> Electronic Shift Lever System >> "P" Position Switch Indicator Light Circuit >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

"P" Position Switch Indicator Light Circuit: Procedure

  1. CHECK TRANSMISSION SHIFT MAIN SWITCH (INDICATOR LIGHT) 
    1. Turn the power switch on (IG).
    2. Depress the brake pedal and move the shift lever to select neutral (N).
    3. Inspect the indicator light condition by operating the P position switch (transmission shift main switch).

      Result

      Condition of Indicator Light Proceed to
      Indicator light does not go off. (Remains on) A
      Indicator light does not come on. B
    4. Turn the power switch off.

    B → See step   4 

    A: Go to next step 

  2. CHECK TRANSMISSION SHIFT MAIN SWITCH (INDICATOR LIGHT) 
    1. Disconnect connector A23 from the transmission control ECU assembly.
    2. Turn the power switch on (IG).
    3. Inspect the indicator light condition by operating the P position switch (transmission shift main switch).

      Result

      Condition of Indicator Light Proceed to
      Indicator light does not go off. (Remains on) A
      Indicator light goes off. B
      NOTE:

      Turning the power switch on (IG) with the transmission control ECU assembly connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection.

    4. Turn the power switch off.
    5. Connect the transmission control ECU assembly connector.

    B → See step   7 

    A: Go to next step 

  3. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - TRANSMISSION SHIFT MAIN SWITCH) 
    1. Disconnect connector A23 from the transmission control ECU assembly.
    2. Disconnect connector from the P position switch (transmission shift main switch).
    3. Measure the resistance according to the value(s) in the table below.
      Fig 1: Identifying Harness And Connector (Transmission Control ECU - Transmission Shift Main Switch)
      GTY293970Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance (Check for Short)

      Tester Connection Switch Condition Specified Condition
      A23-20 (IND) or b1-7 (IND-) - Body ground and other terminals Power switch off 10 kΩ or higher
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Transmission Control ECU Assembly)
      *b Front view of wire harness connector
      (to P Position Switch (Transmission Shift Main Switch))
    4. Connect the P position switch (transmission shift main switch) connector.
    5. Connect the transmission control ECU assembly connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → REPLACE TRANSMISSION SHIFT MAIN SWITCH 

  4. CHECK HARNESS AND CONNECTOR (TRANSMISSION SHIFT MAIN SWITCH POWER SOURCE CIRCUIT) 
    1. Disconnect the connector from the P position switch (transmission shift main switch).
    2. Measure the voltage according to the value(s) in the table below.
      Fig 2: Checking Harness And Connector (Transmission Shift Main Switch Power Source Circuit)
      GTY290136Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Voltage

      Tester Connection Switch Condition Specified Condition
      b1-6 (IND+) - Body ground Power switch off 9 to 14 V
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to P Position Switch (Transmission Shift Main Switch))
    3. Connect the P position switch (transmission shift main switch) connector.

    NG → CHECK AND REPAIR POWER SOURCE CIRCUIT 

    OK: Go to next step 

  5. INSPECT TRANSMISSION SHIFT MAIN SWITCH 
    1. Disconnect the connector from the P position switch (transmission shift main switch).
    2. Apply auxiliary battery voltage between terminals b1-6 (IND+) and b1-7 (IND-) and check the indicator light.
      Fig 3: Identifying Transmission Shift Main Switch Connector
      GTY294060Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Result

      Condition Specified Condition
      Auxiliary battery voltage applied between terminals b1-6 (IND+) and b1-7 (IND-) Comes on
      TEXT IN ILLUSTRATION

      *a Component without harness connected
      (P Position Switch (Transmission Shift Main Switch))

      HINT: 

      Terminals No. 1 and No. 8 on the component side connector are empty.

    3. Connect the P position switch (transmission shift main switch) connector.

    NG → REPLACE TRANSMISSION SHIFT MAIN SWITCH 

    OK: Go to next step 

  6. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - TRANSMISSION SHIFT MAIN SWITCH) 
    1. Disconnect connector A23 from the transmission control ECU assembly.
    2. Disconnect the connector from the P position switch (transmission shift main switch).
    3. Measure the resistance according to the value(s) in the table below.
      Fig 4: Checking Harness And Connector (Transmission Control ECU - Transmission Shift Main Switch)
      GTY292202Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance (Check for Open)

      Tester Connection Switch Condition Specified Condition
      A23-20 (IND) - b1-7 (IND-) Power switch off Below 1 Ω
      TEXT IN ILLUSTRATION

      *a Front view of wire harness connector
      (to Transmission Control ECU Assembly)
      *b Front view of wire harness connector
      (to P Position Switch (Transmission Shift Main Switch))
    4. Connect the P position switch (transmission shift main switch) connector.
    5. Connect the transmission control ECU assembly connector.

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   7 

  7. REPLACE TRANSMISSION CONTROL ECU ASSEMBLY. Refer to  COMPONENTS