СИСТЕМА АВТОМАТИЧЕСКОЙ ТРАНСМИССИИ, Diagnostic DTC:P0741

SYSTEM DESCRIPTION

The ECM uses the signals from the throttle position sensor, air-flow meter, turbine (input) speed sensor, intermediate (counter) shaft 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 DSL, valve body and torque converter clutch.

MONITOR DESCRIPTION

Torque converter lock-up is controlled by the ECM based on the speed sensor (NT), speed sensor (NC), 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 counter gear rpm (NC). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to the shift solenoid DSL. When the shift solenoid DSL 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 DSL or lock-up system performance. The ECM will turn on the MIL and store the DTC.

• 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 75 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.)

INSPECTION PROCEDURE

1. PERFORM ACTIVE TEST

   
   

   1. Warm up the engine.

   2. Turn the ignition switch off.

   3. Connect Intelligent tester to the DLC3.

   4. Turn the ignition switch on (IG).

   5. Select the item "Powertrain / Engine and ECT / Active Test".

   6. According to the display on the tester, perform the "Active Test".

      Tester Display	Test Part	Control Range	Diagnostic Note
      Activate the Lock Up	[Test Details] Control the shift solenoid DSL to set the automatic transaxle to the lock-up condition. [Vehicle Condition] Throttle valve opening angle: Less than 35 % Vehicle Speed: 60 km/h (37 mph) or more	ON/OFF	Possible to check the DSL operation.

      Tech Tips

      
      

      • This test can be conducted when the vehicle speed is 60 km/h (37 mph) or more.

      • This test can be conducted in the 5th gear.

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

      Tech Tips

      
      

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

      • Slowly release, but not fully, the accelerator pedal in order to decelerate. (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 P0741)

   
   

   1. Connect Intelligent tester to the DLC3.

   2. Turn the ignition switch on (IG) and turn the Intelligent tester main switch ON.

   3. When you use Intelligent tester:

      Select the item "Powertrain / Engine and ECT / DTC / Current or Pending".

   4. Read the DTCs using Intelligent tester.

      Result
      Result Proceed to P0741 A P0741 and other DTCs B

      Tech Tips

      If any other codes besides "P0741" are output, perform the troubleshooting for those DTCs first.

   
   

   B

   GO TO DTC CHART Click here

   A

2. INSPECT TRANSMISSION WIRE (DSL)

   
   

   1. 

      Disconnect the transmission wire connector from the transaxle.

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

      Standard resistance
      Tester Connection Condition Specified Condition 10 (DSL) - Body ground 20°C (68°F) 11 to 13 Ω

   
   

   NG

   INSPECT SHIFT SOLENOID VALVE (DSL) Click here

   OK

3. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)

   
   

   1. 

      Connect the transmission wire connector.

   2. Disconnect the ECM connector.

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

      Standard resistance
      Tester Connection Condition Specified Condition B50-34 (DSL) - Body ground 20°C (68°F) 11 to 13 Ω

   
   

   NG

   REPAIR OR REPLACE HARNESS OR CONNECTOR

   OK

4. INSPECT SHIFT SOLENOID VALVE (DSL)

   
   

   1. 

      Remove the shift solenoid valve DSL.

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

      Standard resistance
      Tester Connection Condition Specified Condition Solenoid Connector (DSL) - Solenoid Body (DSL) 20°C (68°F) 11 to 13 Ω

   3. Connect the positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body.

      OK
      The solenoid valve makes an operating sound.

   
   

   NG

   REPLACE SHIFT SOLENOID VALVE (DSL) Click here

   OK

5. CHECK TRANSMISSION WIRE

   OK
   The connectors and pins are securely installed.
   There is no open or short on the wire harness.

   
   

   NG

   REPAIR OR REPLACE TRANSMISSION WIRE Click here

   OK

6. INSPECT TRANSMISSION VALVE BODY ASSEMBLY

   OK
   There are no foreign objects on each valve and they operate smoothly.

   
   

   NG

   REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

   OK

7. INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY

   OK
   The torque converter clutch operates normally.

   
   

   NG

   REPLACE TORQUE CONVERTER CLUTCH ASSEMBLY Click here

   OK

   REPAIR AUTOMATIC TRANSAXLE ASSEMBLY Click here