СИСТЕМА АВТОМАТИЧЕСКОЙ ТРАНСМИССИИ, Diagnostic DTC:P2757

DESCRIPTION

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

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.

MONITOR DESCRIPTION

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

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 shift solenoid valve SLU or lock-up system performance.

The ECM will turn on the MIL and store the DTC.

CAUTION / NOTICE / HINT

1. ACTIVE TEST

   Tech Tips

   Using the GTS 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 GTS to the DLC3.

   4. Turn the ignition switch to ON.

   5. Turn the GTS on.

   6. Enter the following menus: Powertrain / Engine and ECT / Active Test.

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

      
      Powertrain > Engine and ECT > Active Test

      Tester Display	Measurement Item	Control Range	Diagnostic Note
      Activate the Lock Up	Control shift solenoid valve SLU and SL to set the automatic transaxle to lock-up	ON or OFF	Can be used to check shift solenoid valve SLU and SL operation. [Vehicle Condition] Vehicle speed: 60 km/h (37 mph) or more

      
      Powertrain > Engine and ECT > Active Test

      Tester Display
      Activate the Lock Up

   8. Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.

      Tech Tips

      
      

      • When depressing the accelerator pedal while driving, if the engine speed does not change abruptly, lock-up is on.

      • When decelerating, slowly release the accelerator pedal, but do not fully release it (fully releasing the pedal will close the throttle valve and lock-up may be turned off).

      

PROCEDURE

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

   
   

   1. Connect the GTS to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the GTS on.

   4. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.

      
      Powertrain > Engine and ECT > Trouble Codes

   5. Read the DTCs using the GTS.

      Result
      Result Proceed to Only P2757 is output A P2757 and other DTCs are output B

      Tech Tips

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

   
   

   B

   GO TO DTC CHART Click here

   A

2. INSPECT SHIFT SOLENOID VALVE SLU

   
   
   1. 

      *1	Shift Solenoid Valve SLU

      Remove shift solenoid valve SLU.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 1 - 2 20°C (68°F) 5.0 to 5.6 Ω

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

      OK
      Measurement Condition Specified Condition Battery positive (+) with a 21 W bulb → Terminal 1 Battery negative (-) → Terminal 2 Valve moves and makes an operating noise

      Result
      Proceed to OK NG

   
   

   NG

   REPLACE SHIFT SOLENOID VALVE SLU Click here

   OK

3. INSPECT TRANSMISSION VALVE BODY ASSEMBLY

   
   

   1. Check the transmission valve body assembly.

      Click here

      OK
      There are no foreign objects on any valve.

      Result
      Proceed to OK NG

   
   

   NG

   REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

   OK

4. INSPECT TORQUE CONVERTER ASSEMBLY

   
   

   1. Check the torque converter assembly.

      Click here

      OK
      The torque converter operates normally.

      Result
      Proceed to OK NG

   
   

   OK

   REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLY Click here

   NG

   REPLACE TORQUE CONVERTER ASSEMBLY Click here