AUTOMATIC TRANSMISSION SYSTEM (for 1TR-FE), Diagnostic DTC:P2742, P2743

DTC Code DTC Name
P2742 Transmission Fluid Temperature Sensor "B" Circuit Low Input
P2743 Transmission Fluid Temperature Sensor "B" Circuit High Input

DESCRIPTION

The No. 2 ATF temperature sensor is installed in the transmission valve body assembly.

If the ECM detects an abnormally high ATF temperature near this sensor, it illuminates the warning light.

Tech Tips


  • The temperature of ATF easily rises when towing, climbing hills, in traffic, etc.

  • If the No. 2 ATF temperature sensor becomes short-circuited, the signal that indicates that the ATF temperature is 150°C (302°F) or higher is input into the ECM.

Vehicle conditions when the sensor is normal and when the sensor is short-circuited are indicated in the table below.

No. 2 ATF Temperature Sensor State Detection Condition Symptom Recovery Condition
Sensor is normal ATF temperature higher than 150°C (302°F) ATF temperature warning indicator remains on ATF temperature below 135°C (275°F)*1
ATF temperature higher than 130°C (266°F) Shift point too high ATF temperature below 110°C (230°F)
Sensor is short-circuited Any conditions Shift point too high Symptoms still occur
Engine coolant temperature higher than 95°C (203°F) Lock-up at 3rd gear*2 Symptoms still occur

Tech Tips

*1: When ATF temperature is in the normal range, it decreases to below 135°C (275°F) within 5 minutes with the shift lever in P or N in an idling state.

*2: When ATF temperature is normal, transmission lock-up occurs in 4th, 5th and 6th gear with the shift lever in D or the S6 range, in 4th or 5th gear with the shift lever in the S5 range, and 4th gear with the shift lever in the S4 range.

DTC Code DTC Detection Condition Trouble Area
P2742 No. 2 ATF temperature sensor resistance is below 25 Ω for 0.5 seconds or more (1 trip detection logic).

  • Short in No. 2 ATF temperature sensor circuit

  • No. 2 ATF temperature sensor (transmission wire)

  • ECM
P2743

No. 2 ATF temperature sensor resistance is higher than 156 kΩ for 0.5 seconds or more and either condition is met (1 trip detection logic):

(A) 15 minutes or more have elapsed after the engine start when the engine coolant temperature or intake air temperature is -29.375°C (-20.875°F) or less.

(B) 10 seconds or more have elapsed after the engine start when the engine coolant temperature and intake air temperature are higher than -29.375°C (-20.875°F).

  • Open in No. 2 ATF temperature sensor circuit

  • No. 2 ATF temperature sensor (transmission wire)

  • ECM

MONITOR DESCRIPTION

The No. 2 ATF temperature sensor converts the ATF temperature to an electrical resistance value. Based on the resistance, the ECM determines the ATF temperature and detects an open or short in the No. 2 ATF temperature sensor circuit. If the resistance value of the No. 2 ATF temperature sensor is below 25 Ω*1 or higher than 156 kΩ*2, the ECM interprets this as a fault in the No. 2 ATF temperature sensor or wiring. The ECM stores the DTC.

*1: 150°C (302°F) or higher is indicated regardless of the actual ATF temperature.

*2: -40°C (-40°F) is indicated regardless of the actual ATF temperature.

Tech Tips

The ATF temperature can be checked on the GTS display.

WIRING DIAGRAM

Refer to DTC P0712 Click here.

INSPECTION PROCEDURE

Note

Perform registration and/or initialization when parts related to the automatic transmission are replaced Click here.


  1. DATA LIST

    Tech Tips

    Using the GTS to read the Data List allows the values or states of switches, sensors, actuators and other items to be read without removing any parts. This non-intrusive inspection can be very useful because intermittent conditions or signals may be discovered before parts or wiring is disturbed. Reading the Data List information early in troubleshooting is one way to save diagnostic time.

    Note

    In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not.


    1. Warm up the engine.

    2. Turn the engine switch off.

    3. Connect the GTS to the DLC3.

    4. Turn the ignition switch to ON.

    5. Turn the GTS on.

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

    7. According to the display on the GTS, read the Data List.

      Engine and ECT
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      A/T Oil Temperature 2

      No. 2 ATF temperature sensor value/

      Min.: -40°C (-40°F)

      Max.: 150°C (302°F)

      • Approx. 80°C (176°F): After stall test

      • Equal to ambient temperature when cold soak

      		 If the value -40°C (-40°F) or 150°C (302°F), No. 2 ATF temperature sensor circuit is open or shorted.

      Tech Tips


      • When DTC P2742 is output and the GTS indicates 150°C (302°F) or higher, there is a short circuit.

      • When DTC P2743 is output and the GTS indicates -40°C (-40°F), there is an open circuit.

        Check the temperature displayed on the GTS in order to check if a malfunction exists.

      Temperature Displayed Malfunction
      -40°C (-40°F) Open circuit
      150°C (302°F) or higher Short circuit

PROCEDURE


  1. INSPECT NO. 2 ATF TEMPERATURE SENSOR (TRANSMISSION WIRE)


    1. B007TU8E07
      Text in Illustration
      *a

      Component without harness connected

      (Transmission Wire)

      Disconnect the transmission wire connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      5 (OT2+) - 6 (OT2-) Always 25 Ω to 156 kΩ
      5 (OT2+) - Body ground Always 10 kΩ or higher
      6 (OT2-) - Body ground Always 10 kΩ or higher

      Tech Tips

      If the resistance is out of the specified range at any of the ATF temperatures shown in the table below, the driveability of the vehicle may decrease.

      ATF Temperature Specified Condition
      10°C (50°F) 5 to 8 kΩ
      25°C (77°F) 2.5 to 4.5 kΩ
      110°C (230°F) 0.22 to 0.28 kΩ

    NG

    REPLACE NO. 2 ATF TEMPERATURE SENSOR (TRANSMISSION WIRE) Click here

    OK

  2. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)


    1. B007U51E07
      Text in Illustration
      *a

      Front view of wire harness connector

      (to ECM)

      Disconnect the ECM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      D116-85 (THO2) - D116-128 (ETHO) Always 25 Ω to 156 kΩ
      D116-85 (THO2) - Body ground Always 10 kΩ or higher
      D116-128 (ETHO) - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

    REPLACE ECM Click here