AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P0741

DESCRIPTION

The TCM uses signals from the throttle position sensor, air-flow meter, turbine (input) speed sensor, intermediate (counter gear) speed sensor and crankshaft position sensor to help determine the engagement timing of the lock-up clutch. The TCM monitors the engagement of the clutch using the turbine (input) speed sensor, intermediate (counter gear) speed sensor and crankshaft position sensor.

Then the TCM compares the engagement condition of the lock-up clutch with the lock-up schedule in the TCM memory to detect shift solenoid valve SL, valve body and torque converter clutch mechanical problems.

MONITOR DESCRIPTION

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

If the TCM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the TCM interprets this as a fault in shift solenoid valve SL or lock-up system performance. The TCM will turn on the MIL and store the DTC.

INSPECTION PROCEDURE

1. ACTIVE TEST

   Tip:

   Using the intelligent tester 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 intelligent tester to the DLC3.

   4. Turn the ignition switch to ON.

   5. Turn the intelligent tester on.

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

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

      Table 1. ECT

      Tester Display	Test Part	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: 80 km/h (50 mph) or more

   8. 

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

      Tip:
      

      • When changing the accelerator pedal opening angle 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. Click here

   CHECK DTC OUTPUT (IN ADDITION TO DTC P0741)

   
   

   1. Connect the intelligent tester to the DLC3.

   2. Turn the ignition switch to ON.

   3. Turn the intelligent tester on.

   4. Enter the following menus: Powertrain / ECT / DTC.

   5. Read the DTCs using the intelligent tester.

      Table 2. Result

      Result	Proceed to
      Only P0741 is output	A
      P0741 and other DTCs are output	B

      Tip:

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

   
   
   • AClick here
   • BClick here
2. Click here

   INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL)

   
   
   1. 

      Remove the TCM.

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

      Standard Resistance
      Tester Connection Condition Specified Condition 6 (SL) - Body ground 20°C (68°F) 11 to 15 Ω

      Table 3. Text in Illustration

      *a	Component without TCM connected (Transmission Wire)

   
   
   • OKClick here
   • NGClick here
3. Click here

   INSPECT SHIFT SOLENOID VALVE SL (OPERATION)

   
   
   1. 

      Remove shift solenoid valve SL.

   2. 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 (+) → Shift solenoid valve SL connector Battery negative (-) → Shift solenoid valve SL body Valve moves and makes an operating noise

      Table 4. Text in Illustration

      *a	Component without harness connected (Shift Solenoid Valve SL)

   
   
   • OKClick here
   • NGClick here
4. Click here

   INSPECT TRANSMISSION VALVE BODY ASSEMBLY

   
   

   1. Check the transmission valve body assembly (Click here).

      OK
      There are no foreign objects on any valve.

   
   
   • OKClick here
   • NGClick here
5. Click here

   INSPECT TORQUE CONVERTER CLUTCH ASSEMBLY

   
   

   1. Check the torque converter clutch assembly (Click here).

      OK
      The torque converter clutch operates normally.

   
   
   • OKClick here
   • NGClick here
6. Click here

   REPAIR OR REPLACE AUTOMATIC TRANSAXLE ASSEMBLYClick here

7. Click here

   INSPECT SHIFT SOLENOID VALVE SL (RESISTANCE)

   
   
   1. 

      Remove shift solenoid valve SL.

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

      Standard Resistance
      Tester Connection Condition Specified Condition Shift solenoid valve SL connector terminal - Shift solenoid valve SL body 20°C (68°F) 11 to 15 Ω

      Table 5. Text in Illustration

      *a	Component without harness connected (Shift Solenoid Valve SL)

   
   
   • OKClick here
   • NGClick here
8. Click here

   REPLACE TRANSMISSION WIREClick here

9. Click here

   GO TO DTC CHARTClick here

10. Click here

    REPLACE SHIFT SOLENOID VALVE SLClick here

11. Click here

    REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSEMBLYClick here

12. Click here

    REPLACE TORQUE CONVERTER CLUTCH ASSEMBLYClick here

13. Click here

    REPLACE SHIFT SOLENOID VALVE SLClick here