LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Toyota >> 2012 >> Avalon Base >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Smart Key System (Keyless Start) (Diagnostic Codes & Circuit Tests) >> Smart Key System >> DTC B2281: "P" Signal Malfunction >> Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC B2281: "P" Signal Malfunction: Procedure

  1. READ VALUE USING TECHSTREAM 
    1. Connect Techstream to the DLC3.
    2. Turn the engine switch on (IG) and press Techstream main switch on.
    3. Read the DATA LIST according to the displays on the tester.
      POWER SOURCE CONTROL:

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Shift P Signal Shift P Signal / ON or OFF ON: Shift P signal ON (Shift position is P)
      OFF: Shift P signal OFF (Shift position is not P)
      -

      OK

      "ON" (P signal is ON) appears on the screen.

      Result

      Condition Proceed to
      NG C
      OK (When troubleshooting according to the PROBLEM SYMPTOM TABLE) B
      OK (When troubleshooting according to the DTC chart) A

    B → PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN  PROBLEM SYMPTOMS TABLE 

    C → See step   2 

    A → REPLACE POWER SOURCE CONTROL ECU 

  2. CHECK WIRE HARNESS (POWER SOURCE CONTROL ECU - SHIFT LOCK CONTROL ECU) 
    1. Disconnect the D44 ECU connector.
      Fig 1: View Of Disconnected D44 ECU Connector Terminal
      GTY192346Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Disconnect the D25 ECU connector.
      Fig 2: Identifying D25 ECU Connector Terminals
      GTY210307Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    3. Measure the resistance according to the value(s) in the table below.

      Resistance

      Terminal No. (Symbol) Specified Condition
      D44-5 (P) - D25-11 (P2) Below 1 Ω
      D44-5 (P) - Body ground 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK: Go to next step 

  3. CHECK POWER SOURCE CONTROL ECU OPERATION 
    1. After replacing the power source control ECU with a normally functioning ECU, check that the push button start function can start normally.

      OK

      Push button start function can start normally.

    NG → GO TO SHIFT CONTROL SYSTEM Found In  SHIFT LOCK SYSTEM 

    OK → END (POWER SOURCE CONTROL ECU DEFECTIVE)