A340F Automatic Transmission System

A340F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P2757: Torque Converter Clutch Pressure Control Solenoid Performance (Shift Solenoid Valve SLU)
P2757 - Torque Converter Clutch Pressure Control Solenoid Performance (Shift Solenoid Valve SLU)

DESCRIPTION

The ECM uses the signals from the throttle position sensor, mass air-flow meter, turbine (input) speed sensor, output speed sensor and crankshaft position sensor, to monitor the engagement condition of the lock-up clutch.





Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect any mechanical problems with the shift solenoid valve SLU, valve body or torque converter clutch.





MONITOR DESCRIPTION

Torque converter lock-up is controlled by the ECM based on the turbine (input) speed sensor NCO, output speed sensor SP2, engine speed, engine load, engine coolant temperature, vehicle speed, transmission fluid temperature, and gear selection. The ECM determines the lock-up status of the torque converter by comparing the engine speed (NE) with the input turbine speed (NCO). The ECM calculates the actual transmission gear by comparing the input turbine speed (NCO) with the output shaft speed (SP2). When the conditions are appropriate, the ECM requests lock-up by applying the control voltage to the shift solenoid SLU. When the SLU is turned on, the solenoid SLU applies pressure to the lock-up relay valve and locks the torque converter clutch.

If the ECM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the ECM interprets this as a fault in the shift solenoid valve SLU or lock-up system performance.

The ECM turns on the MIL and stores the DTC.

Example:

When any of the following are met, the ECM interprets it as a malfunction.

- (a) There is a difference in rotation between before and after the torque converter even when the ECM requests lock-up.

(Engine speed is at least 70 rpm greater than the input turbine speed.)

- (b) There is no difference in rotation between before and after the torque converter even when the ECM requests lock-up off.

(The difference between the engine speed and input turbine speed is less than 35 rpm.)

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

All





OFF malfunction (A)





OFF malfunction (B)





ON malfunction (A) and (B)





TYPICAL MALFUNCTION THRESHOLDS

OFF malfunction

- Both of the following conditions are met: OFF malfunction (A) and (B)

OFF malfunction (A)





OFF malfunction (B)





ON malfunction

- 2 detections are necessary in 1 driving cycle.

- 1st detection: Temporary flag ON

- 2nd detection: Pending fault code ON

- Vehicle speed must be under 10 km/h (6.2 mph) once before the 2nd detection.

ON malfunction (A)





ON malfunction (B)





COMPONENT OPERATING RANGE





INSPECTION PROCEDURE

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

HINT
Using the Techstream to perform Active Tests allows relays, VSVs, actuators and other items to be operated without removing any parts. This non-intrusive functional inspection can be very useful because intermittent operation may be discovered before parts or wiring is disturbed. Performing Active Tests early in troubleshooting is one way to save diagnostic time. Data List information can be displayed while performing Active Tests.

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 / Active Test.

7. According to the display on the Techstream, perform the Active Test.

Engine and ECT





HINT
This test can be conducted when the vehicle speed is 60 km/h (36 mph) or more.





HINT
* When changing the accelerator pedal opening angle while driving, if the engine speed does not change rapidly, lock-up is on.
* Slowly release the accelerator pedal in order to decelerate, but do not fully release the pedal. (Fully releasing the pedal will close the throttle valve and lock-up may be turned off automatically.)

PROCEDURE

1. CHECK DTC OUTPUT (IN ADDITION TO DTC P2757)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

(e) Read the DTCs using the Techstream.

Result





HINT
If any other codes besides P2757 are output, perform troubleshooting for those DTCs first.

B -- GO TO DTC CHART Automatic Transmission System - A340F
A -- Continue to next step.

2. INSPECT SHIFT SOLENOID VALVE SLU

(a) Remove shift solenoid valve SLU.





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

Standard Resistance:





(c) Apply 12 V battery voltage to the shift solenoid valve and check that the valve moves and makes an operating noise.

OK:





Text in Illustration





NG -- REPLACE SHIFT SOLENOID VALVE SLU Removal
OK -- Continue to next step.

3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY P0751

NG -- REPLACE TRANSMISSION VALVE BODY ASSEMBLY Removal
OK -- Continue to next step.

4. INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY P2714

NG -- REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY Removal

OK -- REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY Removal