Dtc P2742 Transmission Fluid Temperature Sensor B Circuit Low Input


DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

INSPECT TRANSMISSION WIRE (NO. 2 ATF TEMPERATURE SENSOR)

CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - TCM)

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

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


DESCRIPTION

The Automatic Transmission Fluid (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 light.
HINT:
  1. The temperature of the ATF easily rises when towing, climbing hills, in traffic, etc.
  2. If the ATF temperature sensor becomes short-circuited, a signal that indicates that the ATF temperature is 150°C (302°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 light 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 in 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
Shift point too high
Symptoms still occur
Engine coolant temperature higher than 95°C (203°F)
Lock-up in 3rd gear*2
Symptoms still occur
HINT:
*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 ATF temperature is normal, transmission lock-up occurs in 5th gear with the shift lever in D or with the S5 range selected, and in 4th gear with the S4 range selected.

DTC Code
DTC Detection Condition
Trouble Area
P2742
No. 2 ATF temperature sensor resistance is below 25 Ω (0.046 V) for 0.5 sec. or more (1-trip detection logic).
  1. Short in No. 2 ATF temperature sensor circuit
  2. No. 2 ATF temperature sensor (transmission wire)
  3. TCM
P2743
When 15 min. or more have elapsed after the engine is started, No. 2 ATF temperature sensor resistance is higher than 156 kΩ (4.915 V) for 0.5 sec. or more (1-trip detection logic).
  1. Open in No. 2 ATF temperature sensor circuit
  2. No. 2 ATF temperature sensor (transmission wire)
  3. TCM

MONITOR DESCRIPTION

The ATF temperature sensor converts the ATF temperature into an electrical resistance value. Based on the resistance, the TCM determines the ATF temperature and detects an open or short in the ATF temperature circuit. If the resistance value of the ATF temperature sensor is below 25 Ω*1 or higher than 156 kΩ*2, the TCM interprets this as a fault in the ATF sensor or wiring. The TCM will illuminate the MIL and store the DTC.
HINT:
  1. *1: 150°C (302°F) or higher 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 intelligent tester display.

WIRING DIAGRAM

Refer to DTC P0712 (LandCruiser RM0000013US027X_03.html).

INSPECTION PROCEDURE


DATA LIST
HINT:
Using the intelligent tester 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 intelligent tester to the DLC3.

  4. Turn the ignition switch to ON.

  5. Turn the intelligent tester on.

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

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

    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)
    1. After stall test: Approximately 80°C (176°F)
    2. With engine cold: Equal to ambient temperature
    		If the value is -40°C (-40°F) or 150°C (302°F), the No. 2 ATF temperature sensor circuit is open or shorted.
    HINT:
    1. When DTC P2742 is output and the intelligent tester output is 150°C (302°F) or higher, there is a short circuit.
    2. When DTC P2743 is output and the intelligent tester output is -40°C (-40°F), there is an open circuit.
      Check the temperature displayed on the tester 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
1.INSPECT TRANSMISSION WIRE (NO. 2 ATF TEMPERATURE SENSOR)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.A750F Automatic Transmission Transaxle.Automatic Transmission System (For 1Kd-Ftv). Dtc P2742 Transmission Fluid Temperature Sensor B Circuit Low Input

  1. Disconnect the C30 transmission wire connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 (OT2-) - 9 (OT2+)
    		Always
    		25 Ω to 156 kΩ
    1 (OT2-) - Body ground
    		Always
    		10 kΩ or higher
    9 (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
Text in Illustration
*a
Component without harness connected
(Transmission Wire)


NG
REPAIR OR REPLACE NO. 2 ATF TEMPERATURE SENSOR (TRANSMISSION WIRE) (LandCruiser RM0000013C105QX.html)
OK


2.CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - TCM)
Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.A750F Automatic Transmission Transaxle.Automatic Transmission System (For 1Kd-Ftv). Dtc P2742 Transmission Fluid Temperature Sensor B Circuit Low Input

  1. Disconnect the G69 TCM connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    G69-24 (THO2) - G69-23 (E2)
    		Always
    		25 Ω to 156 kΩ
    G69-24 (THO2) - Body ground
    		Always
    		10 kΩ or higher
    G69-23 (E2) - Body ground
    		Always
    		10 kΩ or higher
    Text in Illustration
    *a
    		Rear view of wire harness connector
    (to TCM)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE TCM (LandCruiser RM0000048F300JX.html)