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DTC P2757, P2758: Torque Converter Clutch Pressure Control Solenoid Control Circuit Performance/Stuck Off, Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck On: Notes

Circuit description

The lock-up control solenoid (SLU) is controlled by the duty signal which is predetermined by the transmission control computer ASSY. Then, lock-up and flex lock-up control is performed.

DTC No. SAE/TCCS DTC detecting condition
  1. Diagnosis condition
  2. Abnormal condition
  3. Abnormal period
  4. Other
Inspection parts
P2757
  1. All of the following conditions are established. Learning control is not prohibited. 4 seconds or more passed after shifting to D position. Engine coolant temperature is 40°C or more. ATF temperature is 20°C or more. Gear range is 4th or higher. No malfunction is detected in transmission 3 way solenoid ASSY (S1, S2, S3, S4, SR), clutch control solenoid No. 1 (SL1, SL2), lock-up control solenoid (SLU), line pressure control solenoid ASSY (SLT), transmission revolution sensor (NT, SP2), neutral start switch ASSY, CAN bus, engine ECM communication, engine coolant temperature, electronic throttle control, and accelerator pedal.
  2. All of the following conditions are established.

    3 seconds or more passed after hydraulic command value of lock-up control solenoid (SLU) exceeds the specified value.

    Engine speed is higher than turbine revolution speed by 70 r/min or more.

    Gear range is 4th or higher.

    Throttle opening angle is the specification or more.

    Vehicle speed is 22km/h {14 MPH} or more

  3. seconds or more passed for all conditions of item 2
  4. trips
  • Transmission wire
  • Lock-up control solenoid ASSY (SLU)
  • Transmission control computer ASSY
  • Torque converter ASSY
P2758
  1. All of the following conditions are established. Learning control is not prohibited. 4 seconds or more passed after shifting to D position. Engine coolant temperature is 40°C or more. ATF temperature is 20°C or more. Gear range is 4th or higher.

    No malfunction is detected in transmission 3 way solenoid ASSY (S1, S2, S3, S4, SR), clutch control solenoid No. 1 (SL1, SL2), lock-up control solenoid (SLU), line pressure control solenoid ASSY (SLT), transmission revolution sensor (NT, SP2), neutral start switch ASSY, CAN bus, engine ECM communication, engine coolant temperature, electronic throttle control, and accelerator pedal.

  2. All of the following conditions are established. 3 seconds or more passed after hydraulic command value of lock-up control solenoid (SLU) drops to less than the specified value.

    Difference between engine speed and turbine revolution speed is less than 35 r/min.

    Gear range is 4th or higher.

    Throttle opening angle is the specification or more.

    Vehicle speed is 22km/h {14 MPH} or more

  3. After 2 or more seconds passed for all conditions of item 2, vehicle experiences the speed of less than 10 km/h {6 MPH}, then 2 or more seconds passed for all conditions of item 2.
  4. trips
  • Transmission wire
  • Lock-up control solenoid ASSY (SLU)
  • Transmission control computer ASSY
  • Torque converter ASSY

Monitor description

The torque converter lock-up is controlled by TCM based on the transmission revolution sensor (NT, SP2), engine r/min, engine load, engine temperature, vehicle speed, transmission temperature, and selected gear. TCM compares engine r/min (NE) with input turbine r/min (NT) to determine the lock-up status of the torque converter. TCM compares input turbine r/min (NT) and output shaft r/min (SP2) to calculate the actual transmission gear. If the condition is appropriate, TCM applies control voltage to the lock-up control solenoid (SLU) and requires "lock up". When the lock-up control solenoid (SLU) turns to ON, it applies pressure to the lock up relay valve to lock the torque converter clutch.

If TCM does not detect lock up after the lock up is requested or detects lock up even though it is not requested, TCM recognizes it as a malfunction of the lock-up control solenoid (SLU) or lock up system performance. TCM turns on MIL and records the diagnostic codes.

MONITOR STRATEGY DESCRIPTION

Applicable diagnostic codes P2757: Torque Converter Clutch Pressure Control Solenoid
Control Circuit Performance/Stuck Off
P2758: Torque Converter Clutch Pressure Control Solenoid
Control Circuit Stuck On
Required sensor/component Lock-up control solenoid ASSY (SLU)
Operation frequency Consecutive
Period P2757: 2 seconds
P2758: 1.8 seconds, 2 counts (detecting defects after the vehicle speed becomes less than 10 km/h {6 MPH} after 1 count)
MIL operation 2nd driving cycle
Operation order None

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS DESCRIPTION

Battery voltage 10.5V or more
Engine speed 400 r/min or more
Fail safe mode (solenoid power supply shut down) Non-active
Transmission revolution sensor (NT) (P0717) No defect
Transmission revolution sensor (SP2) (P0722) No defect
Transmission 3 way solenoid ASSY (S1) (P0973, P0974) No defect
Transmission 3 way solenoid ASSY (S2) (P0976, P0977) No defect
Transmission 3 way solenoid ASSY (S3) (P0979, P0980) No defect
Transmission 3 way solenoid ASSY (S4) (P0982, P0983) No defect
Transmission 3 way solenoid ASSY (SR) (P0985, P0986) No defect
Clutch control solenoid No. 1 (SL1) (P0962, P0963, P0961) No defect
Clutch control solenoid No. 1 (SL2) (P0966, P0967, P0965) No defect
Line pressure control solenoid ASSY (SLT) (P2720, P2721, P2719) No defect
Lock-up control solenoid (SLU) (P2762, P2763, P2764) No defect
Neutral start switch ASSY (P0707, P0708) No defect
Oil temperature sensor (P0711, P0712, P0713) No defect
CAN bus OFF (U0073) No defect
ECM without ID (U0100) No defect
ECM communication counter (U0401) No defect
Coolant temperature sensor No defect
Engine torque signal No defect
Throttle opening angle sensor No defect
Accelerator pedal opening angle sensor No defect
Range position D
Time elapsed after D range selection 4 seconds or more
Engine coolant temperature 40°C or more
Target gear position 4th, 5th, 6th
ATF temperature 20°C or more

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS DESCRIPTION

Lock-up control solenoid indication 513 kPa {5.2 kgf/cm2 , 74.4 psi} or more
Above condition is established 3 seconds or more
Engine speed - turbine shaft speed 70 r/min or more
Gear ratio calculated from turbine shaft speed and vehicle speed 4th, 5th, 6th
Throttle opening angle Refer to MAP A 
Vehicle speed 22 km/h {14 MPH} or more
TURBINE SHAFT SPEED AND THROTTLE SPECIFICATIONS

Turbine shaft speed (r/min) 1200 1500 3500 5100 5200
Throttle (%) 12.9 13.4 26 39.6 100
TYPICAL MALFUNCTION THRESHOLDS DESCRIPTION

Lock-up control solenoid indication 4 kPa {0.04 kgf/cm2 , 0.58 psi} or less
Above condition is established 3 seconds or more
Engine speed - turbine shaft speed Less than 35 r/min
Gear ratio calculated from turbine shaft speed and vehicle speed 4th, 5th, 6th
Throttle opening angle Refer to MAP B 
Vehicle speed 22 km/h {14 MPH} or more
TURBINE SHAFT SPEED AND THROTTLE SPECIFICATIONS

Turbine shaft speed (r/min) 1200 1500 2000 5800 5900
Throttle (%) 8.1 8.2 10 40 100