STOP AND START SYSTEM, Diagnostic DTC:P1780

DTC Code DTC Name
P1780 Discrepancy between Neutral Position SW and Shift Position

DESCRIPTION

The engine stop and start ECU detects a malfunction by comparing the shift position signal with the neutral position switch signal input state. When a malfunction occurs, the engine stop and start ECU stores this DTC, blinks the stop and start cancel indicator light, and prohibits the stop and start control.

DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Memory
P1780 Discrepancy between Neutral Position SW and Shift Position

The following condition continues for 1 seconds or more (1 trip detection logic):


  • Open or short in neutral position switch circuit.

  • Neutral position switch

  • Engine stop and start ECU

  • Wire harness or connector

 Blinking DTC stored

WIRING DIAGRAM

A01TAQ9E05
*a Neutral Position Switch
*b Engine Stop and Start ECU

CAUTION / NOTICE / HINT

Note


  • Before replacing the engine stop and start ECU, read the number of starter operations and write it into a new engine stop and start ECU.

    Click here

  • After replacing the engine stop and start ECU or air conditioning amplifier assembly, reset and perform learning of the air conditioning information in the engine stop and start ECU.

    Click here

  • After replacing the engine stop and start ECU or airbag sensor assembly, clear and calibrate the deceleration sensor zero point in the engine stop and start ECU.

    Click here

Tech Tips

Using the GTS, read the freeze frame data before troubleshooting. System condition information is recorded as freeze frame data the moment a DTC is stored. This information can be useful when troubleshooting.

Click here

PROCEDURE


  1. READ VALUE USING GTS (NEUTRAL SWITCH)


    1. Connect the GTS to the DLC3.

    2. Turn the ignition switch to ON.

    3. Turn the GTS on.

    4. Enter the following menus: Powertrain / Stop and Start / Data List / Neutral Switch.


      Powertrain > Stop and Start > Data List
      Tester Display
      Neutral Switch

    5. Read the value when the shift lever is in neutral and any other position

      OK
      Tester Display Condition Normal Condition
      Neutral Switch Shift lever in neutral ON
      Shift lever in any position other than neutral OFF
      Result
      Result Proceed to
      NG A
      OK B

    B

    USE SIMULATION METHOD TO CHECK Click here

    A

  2. CHECK HARNESS AND CONNECTOR (ENGINE STOP AND START ECU - NEUTRAL POSITION SWITCH)


    1. Disconnect the A9 engine stop and start ECU connector.

    2. Disconnect the B100 neutral position switch connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A9-26 (TMVC) - B100-1 (WI) Always Below 1 Ω
      A9-25 (TME2) - B100-3 (F+) Always Below 1 Ω
      A9-27 (TMN) - B100-2 (TMN) Always Below 1 Ω
      A9-26 (TMVC) - Body ground Always 10 kΩ or higher
      B100-1 (WI) - Body ground Always 10 kΩ or higher
      A9-25 (TME2) - Body ground Always 10 kΩ or higher
      B100-3 (F+) - Body ground Always 10 kΩ or higher
      A9-27 (TMN) - Body ground Always 10 kΩ or higher
      B100-2 (TMN) - Body ground Always 10 kΩ or higher
      Result
      Proceed to
      OK
      NG

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  3. CHECK ENGINE STOP AND START ECU (TMN TERMINAL VOLTAGE)


    1. Measure the voltage according to the value(s) in the table below.

      A01TA8UC23
      *a

      Component with harness connected

      (Engine Stop and Start ECU)

      		 - -
      Standard Voltage
      Tester Connection Condition Specified Condition
      A9-27 (TMN) - A9-25 (TME2) Ignition switch ON, shift lever in neutral 2.7 to 4.3 V
      Ignition switch ON, shift lever in any position other than neutral 0.7 to 1.9 V
      Result
      Result Proceed to
      OK A
      NG (for 1AD-FTV) B
      NG (for 1ND-TV) C
      NG (for 1NR-FE) D

    A

    REPLACE ENGINE STOP AND START ECU Click here

    B

    REPLACE NEUTRAL POSITION SWITCH Click here

    C

    REPLACE NEUTRAL POSITION SWITCH Click here

    D

    REPLACE NEUTRAL POSITION SWITCH Click here