DTC    P2742    Transmission Fluid Temperature Sensor "B" Circuit Low Input

DTC    P2743    Transmission Fluid Temperature Sensor "B" Circuit High Input

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DESCRIPTION

The Automatic Transmission Fluid (ATF) temperature sensor is on the transmission, just in front of the oil cooler inlet pipeline.
If the ECM detects an abnormally high ATF temperature near this sensor, the ATF temperature warning light illuminates or a message is displayed in the combination meter.

HINT:
  1. The temperature of ATF easily rises when towing, climbing hills, in traffic, etc.
  2. If the 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 more than 150°C (302°F)
ATF temperature warning light is illuminated or message is displayed in combination meter
ATF temperature less than 135°C (275°F)*1
ATF temperature more than 130°C (266°F)
Shift point too high
ATF temperature less than 110°C (230°F)
When the conditions (a) and (b) are satisfied.
(a) ATF temperature more than 130°C (266°F)
(b) Engine coolant temperature more than 95°C (203°F)
Lock-up at 3rd gear*2
ATF temperature less than 110°C (230°F)*1 and engine coolant temperature more than 95°C (203°F)
Sensor is short-circuited
Any conditions
  1. ATF temperature warning light blinks or message is displayed in combination meter
  2. Shift point too high
Symptoms still occur
Engine coolant temperature more than 95°C (203°F)
Lock-up at 3rd gear*2
Symptoms still occur

HINT:
*1: When ATF temperature is in the normal range, it decreases to less than 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 5th or 6th gear with the shift lever in the D position or S6 range, in 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 less than 25 Ω (0.046 V) for 0.5 seconds or more. (1-trip detection logic)
  1. Short in No. 2 ATF temperature sensor circuit
  2. No. 1 transmission wire (No. 2 ATF temperature sensor)
  3. ECM
P2743
No. 2 ATF temperature sensor resistance is higher than 156 kΩ (4.915 V) for 0.5 sec. or more and either condition is met (1-trip detection logic):
(A) 15 min. 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 sec. 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).
  1. Open in No. 2 ATF temperature sensor circuit
  2. No. 1 transmission wire (No. 2 ATF temperature sensor)
  3. ECM

MONITOR DESCRIPTION

The ATF temperature sensor converts the ATF temperature into an electrical resistance value. Based on the resistance, the ECM determines the ATF temperature, and the ECM detects an open or short in the ATF temperature circuit. If the resistance value of the ATF temperature is less than 25 Ω*1 or more than 156 kΩ*2, the ECM interprets this as a fault in the ATF temperature sensor or wiring. The ECM stores a DTC, and the ATF temperature warning light blinks or a message is displayed in the combination meter.

HINT:
  1. *1: 150°C (302°F) or more is indicated regardless of the actual ATF temperature.
  2. *2: -40°C (-40°F) is indicated regardless of the actual ATF temperature.
  3. The ATF temperature can be checked on the Techstream display.

WIRING DIAGRAM

Refer to DTC P0712 (Click here).

INSPECTION PROCEDURE


DATA LIST

HINT:
Using the Techstream 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.

NOTICE:
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 ignition switch off.

  3. Connect the Techstream to the DLC3.

  4. Turn the ignition switch to ON.

  5. Turn the Techstream on.

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

  7. According to the display on the Techstream, 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.: 215°C (419°F)
    1. After stall test: Approximately 80°C (176°F)
    2. With engine cold: Equal to ambient temperature
    If value is -40°C (-40°F) or 215°C (419°F), No. 2 ATF temperature sensor circuit is open or shorted

    HINT:
    1. When DTC P2742 is output and the Techstream output is 150°C (302°F) or more, there is a short circuit.
    2. When DTC P2743 is output and the Techstream output is -40°C (-40°F), there is an open circuit.
      Check the temperature displayed on the Techstream in order to check if a malfunction exists.

    Temperature Displayed
    Malfunction
    -40°C (-40°F)
    Open circuit
    150°C (302°F) or more
    Short circuit
1.INSPECT NO. 1 TRANSMISSION WIRE (NO. 2 ATF TEMPERATURE SENSOR)


    C159421E18
  1. Disconnect the D63 No. 1 transmission wire connector.

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

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

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

    Resistance (Reference):
    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
REPAIR OR REPLACE NO. 1 TRANSMISSION WIRE (NO. 2 ATF TEMPERATURE SENSOR) (Click here)
OK


2.CHECK HARNESS AND CONNECTOR (NO. 1 TRANSMISSION WIRE - ECM)


    C159422E18
  1. Disconnect the D74 ECM connector.

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

    Standard resistance:
    Tester Connection
    Condition
    Specified Condition
    D74-99 (THO2) - D74-98 (ETHA)
    Always
    25 Ω to 156 kΩ
    D74-99 (THO2) - Body ground
    Always
    10 kΩ or higher
    D74-98 (ETHA) - Body ground
    Always
    10 kΩ or higher
    Result 
    Result
    Proceed to
    NG
    A
    OK (for 3UR-FE)
    B
    OK (for 3UR-FBE)
    C


B
REPLACE ECM (Click here)

C
REPLACE ECM (Click here)
A

REPAIR OR REPLACE HARNESS OR CONNECTOR