A750E Automatic Transmission System
A750E AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P2740,P2742,P2743: Transmission Fluid Temperature Sensor "B" Circuit
P2743 - Transmission Fluid Temperature Sensor "B" Circuit High Input
DESCRIPTION
The No. 2 Automatic Transmission Fluid (ATF) temperature sensor is on the transmission, just before the oil cooler inlet pipeline.
If the ECM detects an abnormally high ATF temperature through this sensor, it illuminates the warning light to indicate the problem to the driver.
HINT
* The ATF temperature is liable to increase under vehicle conditions such as towing, climbing hills or in traffic.
* If there is a short malfunction in the No. 2 ATF temperature sensor, the ECM receives signals from the sensor, which indicates that the ATF temperature is 150°C (302°F) or more.
The symptoms and recovery conditions, when the sensor is normal or there is a short malfunction in the sensor, are as shown in the table below.
HINT
*1: When the ATF temperature is normal, the transmission locks up in 5th gear with the shift lever in D and in 4th gear with the shift lever in 4.
*2: When the ATF temperature is in the normal range, it decreases to less than 135°C (275°F) within 5 minutes of the shift lever being moved to P or N, while idling.
for Mexico models
MONITOR DESCRIPTION
These DTCs indicate an open or short in the No. 2 Automatic Transmission Fluid (ATF) temperature sensor circuit. 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 any open or short malfunctions in the No. 2 ATF temperature sensor circuit. If the resistance (voltage) of the No. 2 ATF temperature sensor is less than 25 Ohms (0.046 V) or more than 156 kOhms (4.915 V), the ECM interprets this as a fault in the No. 2 ATF temperature sensor or its wiring. The ECM turns on the MIL* and stores a DTC.
*: for Mexico models
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTICE:
Perform the universal trip to clear permanent DTCs DTC Check / Clear.
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
HINT
When DTC P2742 is output and the Techstream reading is 150°C (302°F) or more, there is a short circuit.
When DTC P2743 is output and the Techstream reading 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.
PROCEDURE
1. INSPECT TRANSMISSION WIRE (NO. 2 ATF TEMPERATURE SENSOR)
(a) Disconnect the transmission wire connector from the transmission.
(b) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
HINT
If the resistance is outside the specified range at either of the ATF temperatures shown in the table below, the driveability of the vehicle may decrease.
NG -- REPAIR OR REPLACE TRANSMISSION WIRE Removal
OK -- Continue to next step.
2. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)
(a) Connect the transmission wire connector to the transmission.
(b) Disconnect the connectors from the ECM.
(c) Measure the resistance according to the value(s) in the table below.
Standard Resistance:
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM Removal