P2757

DTC Code	DTC Name
P2757	Torque Converter Clutch Pressure Control Solenoid Performance (Shift Solenoid Valve SLU)

SYSTEM DESCRIPTION

The TCM 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.

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 SLU, valve body and torque converter assembly mechanical problems.

DTC No.	DTC Detection Condition Diagnosis Condition Malfunction Status Malfunction Time Other	Trouble Area
P2757	Coolant temperature 40°C or higher, ATF temperature -10°C or higher, driving with the shift lever in D, and no malfunctions detected in the SL1, SL2, SL3, SL4 solenoids, transmission revolution sensors (NT and NC) or ATF temperature sensor. Lock-up does not occur when requested. 3.5 seconds or more 2 trip detection logic	Shift solenoid valve SLU remains open or closed Valve body is blocked Torque converter assembly Automatic transaxle (clutch, brake or gear, etc.) Line pressure is too low
Coolant temperature 40°C or higher, ATF temperature -10°C or higher, driving with the shift lever in D, and no malfunctions detected in the SL1, SL2, SL3, SL4 solenoids, transmission revolution sensors (NT and NC) or ATF temperature sensor. Lock-up occurs when shift solenoid valve SLU is requested to turn on in the lock-up range. 1.8 seconds or more 2 trip detection logic

DTC No.

DTC Detection Condition

Diagnosis Condition
Malfunction Status
Malfunction Time
Other

Trouble Area

P2757

Coolant temperature 40°C or higher, ATF temperature -10°C or higher, driving with the shift lever in D, and no malfunctions detected in the SL1, SL2, SL3, SL4 solenoids, transmission revolution sensors (NT and NC) or ATF temperature sensor.
Lock-up does not occur when requested.
3.5 seconds or more
2 trip detection logic

Shift solenoid valve SLU remains open or closed
Valve body is blocked
Torque converter assembly
Automatic transaxle (clutch, brake or gear, etc.)
Line pressure is too low

Coolant temperature 40°C or higher, ATF temperature -10°C or higher, driving with the shift lever in D, and no malfunctions detected in the SL1, SL2, SL3, SL4 solenoids, transmission revolution sensors (NT and NC) or ATF temperature sensor.
Lock-up occurs when shift solenoid valve SLU is requested to turn on in the lock-up range.
1.8 seconds or more
2 trip detection logic

MONITOR DESCRIPTION

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

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 SLU or lock-up system performance.

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

Example:

When any of the following is met, the system judges it as a malfunction.

There is a difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter when the TCM commands lock-up.

(Engine speed is at least 70 rpm greater than input turbine speed.)
There is no difference in rotation (speed) between the input side (engine speed) and output side (input turbine speed) of the torque converter when the TCM commands lock-up off.

(The difference between engine speed and input turbine speed is less than 20 rpm.)

INSPECTION PROCEDURE

Tech Tips

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.

ACTIVE TEST

Warm up the engine.
Turn the engine switch off.
Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the intelligent tester on.
Enter the following menus: Powertrain / ECT / Active Test.

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

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

Tester Display

Test Part

Control Range

Diagnostic Note

Activate the Lock Up

Control the shift solenoid SLU and SL to set the automatic transaxle to the lock-up condition.

ON/OFF

Can be used to check operation of the shift solenoid SLU and SL.

[Vehicle Condition]

Vehicle speed: 60 km/h (37 mph) or more

Tech Tips

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

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

CHECK OTHER DTCS OUTPUT (IN ADDITION TO DTC P2757)

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Turn the intelligent tester on.
Enter the following menus: Powertrain / ECT / DTC.

Read the DTCs using the intelligent tester.

Result

Display (DTC output)	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

INSPECT SHIFT SOLENOID VALVE SLU

Text in Illustration

*1 Shift Solenoid Valve SLU

Remove shift solenoid valve SLU.

Text in Illustration
*1	Shift Solenoid Valve SLU

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

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

OK

Valve moves and makes an operating sound.

OK
Valve moves and makes an operating sound.

NG

REPLACE SHIFT SOLENOID VALVE SLU Click here

OK

INSPECT TRANSMISSION VALVE BODY ASSEMBLY
1. Check the transmission valve body assembly Click here.
  
  OK
  
  There are no foreign objects on each valve and they operate smoothly.
NG
REPLACE TRANSMISSION VALVE BODY ASSEMBLY Click here

OK
INSPECT TORQUE CONVERTER ASSEMBLY
1. Check the torque converter assembly Click here.
  
  OK
  
  The torque converter assembly operates normally.
NG
REPLACE TORQUE CONVERTER ASSEMBLY Click here

OK

REPLACE AUTOMATIC TRANSMISSION ASSEMBLY Click here

AUTOMATIC TRANSAXLE SYSTEM, Diagnostic DTC:P2757