P2757

DTC P2757 Torque Converter Clutch Pressure Control Solenoid Performance (Shift Solenoid Valve SLU)

DESCRIPTION
The ECM uses the signals from the throttle position sensor, 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 a mechanical problems of the shift solenoid valve SLU, valve body and torque converter clutch.





MONITOR DESCRIPTION
Torque converter lock-up is controlled by the ECM based on the turbine (input) speed sensor NT, output speed sensor SP2, engine rpm, engine load, engine temperature, vehicle speed, transmission temperature, and gear selection. The ECM determines the lock-up status of the torque converter by comparing the engine rpm (NE) to the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing input turbine rpm (NT) to output shaft rpm (SP2). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to the shift solenoid SLU. When the SLU is turned on, it 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 will turn on the MIL and store the DTC. Example: When either of the following is met, the system judges it as a malfunction.
- There is a difference in rotation between the input side (engine speed) and output side (input turbine speed) of the torque converter when the ECM commands lock-up.
(Engine speed is at least 70 rpm greater than input turbine speed.)
- There is no difference in rotation between the input side (engine speed) and output side (input turbine speed) of the torque converter when the ECM commands lock-up off.
(The difference between engine speed and input turbine speed is less than 35 rpm.)

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

Part 1:

Part 2:

TYPICAL MALFUNCTION THRESHOLDS





INSPECTION PROCEDURE
1. ACTIVE TEST

HINT: Performing the intelligent tester's or Techstream's Active Test allows relay, VSV, actuator and other items to be operated without removing any parts. Performing the Active Test early in troubleshooting is one way to save time. The Data List can be displayed during the Active Test.

(a) Warm up the engine.
(b) Turn the ignition switch OFF.
(c) Connect the intelligent tester or Techstream to the DLC3.
(d) Turn the ignition switch ON and push the tester switch ON.
(e) Enter the following menus:
(1) Intelligent tester - Select: DIAGNOSIS / OBD/MOBD / ECT / ACTIVE TEST /
(2) Techstream - Select: Powertrain / Engine and ECT / Active Test /
(f) Follow the instructions on the tester and perform the Active Test.
(1) Intelligent tester

ECT:

(2) Techstream

ECT:

HINT:
^ This test can be conducted when the vehicle speed is 60 km/h (36 mph) or more.
^ This test can be conducted with the 5th gear.

(g) Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.





HINT:
^ When changing the accelerator pedal opening angle while driving, if the engine speed does not change, 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.)

Step 1:

Step 1-3:

Step 3-4: