MULTI-MODE MANUAL TRANSAXLE SYSTEM, Diagnostic DTC:P0725

DTC Code DTC Name
P0725 Engine Speed Input Circuit

DESCRIPTION

The ECM detects the engine speed signals (NE) using the crankshaft position (CKP) sensor. The transmission control ECU controls the transmission in accordance with two engine speed signals. One signal is received directly from the ECM through a serial communication line. The other signal is received from the ECM via the Controller Area Network (CAN) communication. If the transmission control ECU detects no engine speed signals despite the engine speed signal via CAN being received while the vehicle is running, the ECU interprets this as a malfunction in the engine speed signal circuit. The ECU sets the DTC and illuminates the multi-mode manual transmission warning light.

DTC No. DTC Detection Condition Trouble Area
P0725

The transmission control ECU detects the following conditions simultaneously:

(1 trip detection logic)


  1. Engine speed is 400 rpm or less (serial communication circuit)

  2. Engine speed is 400 rpm or more (CAN communication circuit)

  3. Engine speed difference between signal from serial communication circuit and signal from CAN communication circuit is 400 rpm or more for 1.0 second

  • Wire harness or connector

  • Transmission control ECU

  • ECM

WIRING DIAGRAM

A0138G3E02

INSPECTION PROCEDURE

Note

In ECM replacement, perform the electronic throttle learning after installing the ECM Click here

PROCEDURE


  1. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0725)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Multi-Mode M/T / DTC.

    5. Read DTCs and write them down.

    6. Enter the following menus: Powertrain / Engine and ECT.

    7. Read DTCs.

      Result
      Display (DTC Output) Proceed To
      P0725 A
      P0725, and P0335 and/or P0336 B

      Check the DTC output related to the engine speed signal circuit in the engine control system and the multi-mode manual transmission control system. If DTC P0335 and/or P0336 are set together with DTC P0725, troubleshoot those DTCs first.


    B

    GO TO DTC CHART (EFI SYSTEM) Click here

    A

  2. READ VALUE USING INTELLIGENT TESTER (ENGINE REVOLUTION AND BACKUP ENGINE SPEED)


    1. Connect the intelligent tester to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the tester on.

    4. Enter the following menus: Powertrain / Multi-Mode M/T / Data List / Engine Revolution and Backup Engine Speed.

    5. Check the engine speed value displayed on the tester.

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note

      Engine Revolution

      [Engine Rev]

      Engine revolution per minute:

      Min.: 0 rpm, Max.: 16383.75 rpm

      		 790 to 890 rpm: Idling If NE signal circuit has a short or open circuit, back-up engine speed data from CAN communication displayed

      Backup Engine Speed

      [Bacup Engin Spd]

      Back-up engine speed:

      Min.: 0 rpm, Max.: 8160 rpm

      		 790 to 890 rpm: Idling 0 rpm displayed when malfunction in CAN communication
      OK
      The difference between Engine Speed value and Backup Engine Speed value is constantly less than 400 rpm.

    NG

    INSPECT TRANSMISSION CONTROL ECU Click here

    OK

    CHECK FOR INTERMITTENT PROBLEMS Click here

  3. INSPECT TRANSMISSION CONTROL ECU

    A01379XE05
    Text in Illustration
    *a

    Component with harness connected

    (Transmission Control ECU)

    1. Turn the ignition switch to ON.

    2. Check the signal waveform between the NE terminal and body ground.

      Tester Settings
      Terminals NE (A28-10) - Body ground
      Equipment Settings 5 V/DIV, 1 ms/DIV
      Condition Engine idling
      OK
      A waveform similar to that in the illustration is output.

    NG

    CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - ECM) Click here

    OK

  4. REPLACE TRANSMISSION CONTROL ECU


    1. Replace the transmission control ECU Click here.


    NEXT

  5. PERFORM INITIALIZATION


    1. Perform the initialization and learning for multi-mode manual transaxle system Click here.


    NEXT

    END

  6. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - ECM)


    1. Disconnect the A28 transmission control ECU connector.

    2. Disconnect the B26 ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A28-10 (NE) - B26-15 (NEO) Always Below 1 Ω
      A28-10 (NE) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here