Dtc P2742 Transmission Fluid Temperature Sensor B Circuit Low Input

Drivetrain. Land Cruiser. Urj200, 202 Grj200 Vdj200
Ab60F Automatic Transmission Transaxle. Land Cruiser. Urj200, 202 Grj200 Vdj200

DESCRIPTION

MONITOR DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

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

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

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 ECM detects an abnormally high ATF temperature near this sensor, it illuminates the warning light.
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 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 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
  1. ATF temperature warning light blinks or message is displayed in combination meter
  2. 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
HINT:
*1: When the 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 the ATF temperature is normal, transmission lock-up occurs in 5th or 6th gear with the shift lever in D or the 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
The 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. 1 transmission wire (No. 2 ATF temperature sensor)
  3. ECM
P2743
When 15 min. or more have elapsed after the engine is started, the 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. 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 below 25 Ω*1 or higher than 156 kΩ*2, the ECM interprets this as a fault in the ATF 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 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 (Click here).

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 stored and the intelligent tester output is 150°C (302°F) or higher, there is a short circuit.
    2. When DTC P2743 is stored 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 NO. 1 TRANSMISSION WIRE (NO. 2 ATF TEMPERATURE SENSOR)


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Ab60F Automatic Transmission Transaxle.Automatic Transmission System (For 1Ur-Fe). Dtc P2742 Transmission Fluid Temperature Sensor B Circuit Low Input

  1. Disconnect the 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 of 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. 2 ATF TEMPERATURE SENSOR (NO. 1 TRANSMISSION WIRE) (Click here)
OK


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


    Land Cruiser. Urj200, 202 Grj200 Vdj200.Ab60F Automatic Transmission Transaxle.Automatic Transmission System (For 1Ur-Fe). Dtc P2742 Transmission Fluid Temperature Sensor B Circuit Low Input

  1. Disconnect the ECM connector.

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

    Standard Resistance:
    for LHD
    Tester Connection
    		Condition
    		Specified Condition
    C45-121 (THO2) - C45-122 (ETHA)
    		Always
    		25 Ω to 156 kΩ
    C45-121 (THO2) - Body ground
    		Always
    		10 kΩ or higher
    C45-122 (ETHA) - Body ground
    		Always
    		10 kΩ or higher
    for RHD
    Tester Connection
    		Condition
    		Specified Condition
    C46-121 (THO2) - C46-122 (ETHA)
    		Always
    		25 Ω to 156 kΩ
    C46-121 (THO2) - Body ground
    		Always
    		10 kΩ or higher
    C46-122 (ETHA) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM (Click here)