P2757

AB60E AUTOMATIC TRANSMISSION / TRANSAXLE: AUTOMATIC TRANSMISSION SYSTEM: P2757: Torque Converter Clutch Pressure Control Solenoid Performance (Shift Solenoid Valve SLU)

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 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 illuminate the MIL and store the DTC.
Example: When one of the following conditions is met, the system determines that there is 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 ON.
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

All





OFF Malfunction (A)





OFF Malfunction (B)





ON Malfunction





TYPICAL MALFUNCTION THRESHOLDS

- OFF malfunction is detected when OFF malfunction (A) and (B) are met.

OFF Malfunction (A)





OFF Malfunction (B)





ON malfunction
- 2 detections are necessary per 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 2nd detection.





COMPONENT OPERATING RANGE





INSPECTION PROCEDURE

1. ACTIVE TEST

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.

(a) Warm up the engine.
(b) Turn the ignition switch off.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON.
(e) Turn the Techstream on.
(f) Enter the following menus: Powertrain / Engine and ECT / Active Test.
(g) 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.
- Perform this test while driving in the 5th or 6th gear.

(h) 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.)

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
A -- Continue to next step.

2. INSPECT SHIFT SOLENOID VALVE SLU
(a) Remove the shift solenoid valve SLU.





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

Standard Resistance:





(c) Connect the battery positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector. Then check that the valve moves and makes an operating noise.
OK:
Valve moves and makes an operating noise.

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

3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY
(a) Check the transmission valve body assembly.
OK:
There are no foreign objects on each valve.

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

4. INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY
(a) Check the torque converter clutch assembly Testing and Inspection.
OK:
The torque converter clutch operates normally.

NG -- REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY
OK -- REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSEMBLY