AUTOMATIC TRANSMISSION SYSTEM, Diagnostic DTC:P2742, P2743

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

DESCRIPTION

The No. 2 ATF temperature sensor is on the transmission, just in front of the oil cooler inlet pipeline.

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

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 193°C (379.4°F) or higher is input into the TCM.

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)

When conditions (a) and (b) are satisfied.

(a) ATF temperature higher than 130°C (266°F)

(b) Engine coolant temperature higher than 95°C (203°F)

 Lock-up at 3rd gear*2 ATF temperature below 110°C (230°F)*1 and engine coolant temperature higher than 95°C (203°F)
Sensor is short-circuited Any conditions

  • ATF temperature warning indicator remains on

  • 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 the ATF is normal, 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 the ATF temperature is normal, transmission lock-up occurs in 5th, 6th, 7th or 8th gear with the shift lever in D or with the S8 range selected, in 5th, 6th or 7th gear with the S7 range selected, in 5th or 6th gear with the S6 range selected and in 5th gear with the S5 range selected.

DTC Code

DTC Detection Condition


  1. Diagnosis Condition

  2. Malfunction Status

  3. Malfunction Time

  4. Other

 Trouble Area
P2742

  1. The battery voltage is 9.5 V or higher.

  2. No. 2 ATF temperature sensor voltage is below 0.08 V

  3. 60 seconds

  4. 1-trip detection logic

  • Short in No. 2 ATF temperature sensor circuit

  • No. 2 ATF temperature sensor

  • TCM
P2743

  1. The battery voltage is 9.5 V or higher, engine speed is more than 400 rpm and shift lever in D.

  2. No. 2 ATF temperature sensor voltage is higher than 4.94 V

  3. 12 seconds

  4. 1-trip detection logic

  • Open in No. 2 ATF temperature sensor circuit

  • No. 2 ATF temperature sensor

  • TCM

MONITOR DESCRIPTION

The No. 2 ATF temperature sensor converts the ATF temperature into an electrical resistance value. Based on the resistance, the TCM determines the ATF temperature, and the TCM 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 79 Ω*1 or higher than 156 kΩ*2, the TCM interprets this as a fault in the No. 2 ATF temperature sensor or wiring. The TCM stores a DTC.

Tech Tips


  • *1: 193°C (379.4°F) or higher is indicated regardless of the actual ATF temperature.

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

  • The ATF temperature can be checked on the GTS display.

WIRING DIAGRAM

A01X7GKE03
*a THOC
*b No. 2 ATF Temperature Sensor

CAUTION / NOTICE / HINT

Note

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

Tech Tips

After performing repair, clear the DTCs and perform the following procedure to check that DTCs are not output.


  1. Start the engine.

  2. Wait for 60 seconds or more with the shift lever in D.

  3. Check for DTCs again Click here.


  1. DATA LIST

    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.

    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.


    1. Warm up the engine.

    2. Turn the engine switch off.

    3. Connect the GTS to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the GTS on.

    6. Enter the following menus: Powertrain / ECT / Data List / A/T Oil Temperature 3.

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

      ECT
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      A/T Oil Temperature 3

      No. 2 ATF temperature sensor value/

      Min.: -40°C (-40°F)

      Max.: 193°C (379.4°F)

      • After stall speed test: Approximately 80°C (176°F)

      • While engine is cold: Equal to ambient temperature

      		 If value is -40°C (-40°F) or 193°C (379.4°F), No. 2 ATF temperature sensor circuit is open or short circuited

      Tech Tips


      • When DTC P2742 is stored and the GTS shows 193°C (379.4°F) or higher, there is a short circuit.

      • When DTC P2743 is stored and the GTS shows -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 or short circuit
      193°C (379.4°F) or higher Short circuit

PROCEDURE


  1. READ VALUE USING GTS (A/T OIL TEMPERATURE 3)


    1. Warm up the engine.

    2. Turn the engine switch off.

    3. Connect the GTS to the DLC3.

    4. Turn the engine switch on (IG).

    5. Turn the GTS on.

    6. Enter the following menus: Powertrain / ECT / Data List / A/T Oil Temperature 3.

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

      ECT
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      A/T Oil Temperature 3

      No. 2 ATF temperature sensor value/

      Min.: -40°C (-40°F)

      Max.: 193°C (379.4°F)

      • After stall speed test: Approximately 80°C (176°F)

      • While engine is cold: Equal to ambient temperature

      		 If value is -40°C (-40°F) or 193°C (379.4°F), No. 2 ATF temperature sensor circuit is open or short circuited
      Result
      Result Proceed to
      Data List value is not within the normal condition A
      Data List value is within the normal condition B

    B

    REPLACE TCM Click here

    A

  2. CHECK HARNESS AND CONNECTOR (NO. 2 ATF TEMPERATURE SENSOR - TCM)


    1. A01X458E02
      Text in Illustration
      *a

      Rear view of wire harness connector

      (to TCM)

      Disconnect the TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      A80-26 (THOC) - A80-25 (ETH2) Always 79 Ω to 156 kΩ
      A80-26 (THOC) - Body ground Always 10 kΩ or higher
      A80-25 (ETH2) - 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
      20°C (68°F) 10.3 to 13.9 kΩ
      110°C (230°F) 0.68 to 0.88 kΩ

    OK

    REPLACE TCM Click here

    NG

  3. CHECK HARNESS AND CONNECTOR (NO. 2 ATF TEMPERATURE SENSOR - TCM)


    1. Disconnect the C172 No. 2 ATF temperature sensor connector.

    2. Disconnect the A80 TCM connector.

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      C172-1 (OT2+) - A80-26 (THOC) Always Below 1 Ω
      C172-2 (OT2-) - A80-25 (ETH2) Always Below 1 Ω
      C172-1 (OT2+) or A80-26 (THOC) - Body ground Always 10 kΩ or higher
      C172-2 (OT2-) or A80-25 (ETH2) - Body ground Always 10 kΩ or higher

    OK

    REPLACE NO. 2 ATF TEMPERATURE SENSOR Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR