A340E Automatic Transmission System

A340E AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0712,P0713: Transmission Fluid Temperature Sensor "A" Circuit Low Input


DESCRIPTION

The ATF (Automatic Transmission Fluid) temperature sensor converts the fluid temperature into a resistance value which is input into the ECM. The No. 2 ATF temperature sensor is on the transmission, just before the oil cooler inlet pipeline.

HINT
The ATF temperature is liable to increase under conditions such as towing, climbing hills and in traffic.

The table below shows the symptoms and recovery conditions for when the sensor is normal and when the sensor has a short circuit.





HINT
*1: When the ATF temperature is normal, the transmission locks up in 4th gear with the shift lever in the D position and in 3rd gear with the shift lever in the 3rd position.





MONITOR DESCRIPTION

The Automatic Transmission Fluid (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 ATF temperature circuit. If the resistance of the ATF temperature is less than 79 Ohms or more than 156 kOhms, the ECM interprets this as a fault in the ATF temperature sensor or its wiring. The ECM stores a DTC.

WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Perform the universal trip to clear permanent DTCs DTC Check / Clear.

HINT
According to the Data List displayed by Techstream, you can read the values of switches, sensors, actuators and so on without removing parts. Reading the Data List as the first step of troubleshooting is one method to save 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 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 / All Data.

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

Engine and ECT





HINT
When DTC P0712 is output and Techstream reading is 150°C (302°F) or more, there is a short circuit.

When DTC P0713 is output and Techstream reading 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.





HINT
If a circuit related to the ATF temperature sensor becomes open, P0713 is immediately set (in 0.5 seconds).

PROCEDURE

1. INSPECT TEMPERATURE SENSOR





(a) Disconnect the ATF temperature sensor connector from the transmission.

(b) Measure the resistance between the sensor connector terminals.

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 (ATF TEMPERATURE - ECM)





(a) Connect the transmission wire connector.

(b) Disconnect the ECM connector.

(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