NO.17 EXCESSIVE SHIFT SHOCK FROM N TO D OR N TO R POSITION/RANGE [SJ6A-EL]

id050307802200

17
Excessive shift shock from N to D or N to R position/range
DESCRIPTION
•  Strong shock is felt when shifting from N to D or N to R position/range at idle.
POSSIBLE CAUSE
•  Shift shock may worsen when the fail-safe is operating. If no DTC is output, the shift shock may worsen due to poor operation of the control valve body or sticking of the clutch.
―  Clutch burnt (N→D: C1 clutch, N→R: C3 clutch or B4 brake)
•  ATF level low
•  Line pressure low
•  Incorrect throttle position signal
•  Incorrect accelerator pedal position signal
•  Incorrect engine speed signal
•  Incorrect engine coolant temperature signal
•  Incorrect engine torque signal
•  Incorrect turbine sensor signal (N→D)
•  TFT sensor malfunction
•  Sensor GND malfunction
•  Shift solenoid A malfunction
•  Shift solenoid F malfunction
•  Line pressure control solenoid malfunction
•  TCC control solenoid malfunction (N→R)
•  Control valve body malfunction
―  Poor hydraulic operation (Malfunction in range change)
―  Idle speed high
―  Poor tightening torque of engine mount, exhaust mount, suspension, propeller shaft
―  Line pressure high
―  Insufficient battery voltage
―  Harness or connector malfunction
―  AT malfunction
Note
•  Before following the troubleshooting steps, make sure that the Automatic Transmission On-Board Diagnostic and Automatic Transmission Basic Inspection are conducted. (See BASIC INSPECTION [SJ6A-EL].)

Diagnostic procedure

STEP

INSPECTION

ACTION
1
•  Does the shift shock occur only when the engine is cold?
Yes
Go to the next step.
No
Go to Step 3.
2
•  Inspect the TFT sensor and related wiring harness (vibration, intermittent open/short circuit).
•  Is it normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
3
•  Perform the initial learning procedure.
•  Does the symptom eliminate?
Yes
Symptom troubleshooting is completed.
No
Go to the next step.
4
•  Is the line pressure normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
5
•  Is the stall speed normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
6
•  Access the following PCM PIDs using the M-MDS:
―  RPM
―  APP
―  TP
―  ECT
•  Are the PIDs value normal?
Yes
Go to the next step.
No
Repair or replace the malfunctioning part according to the inspection results.
7
•  Stop the engine.
•  Inspect the following solenoids:
―  Line pressure control solenoid
―  Shift solenoid A
―  Shift solenoid F
―  TCC control solenoid
•  Are these solenoids normal?
Yes
Inspect the ATF condition.
•  If a large amount of metal specks are found, overhaul the transmission and repair or replace any malfunctioning parts.
(See Automatic Transmission Workshop Manual [SJ6A-EL].)
•  If a large amount of metal specks are not found, replace the control valve body.
No
•  Replace the control valve body.
8
•  Verify test results.
―  If normal, return to the diagnostic index to service any additional symptoms.
―  If malfunction remains, inspect the related Service Information and perform repair or diagnosis.
•  If the vehicle is repaired, troubleshooting completed.
•  If the vehicle is not repaired or additional diagnostic information is not available, replace the TCM. (See TCM REMOVAL/INSTALLATION [SJ6A-EL].)


Initial Learning

Warning
•  When performing a initial learning, be aware of other vehicles, people, and other impediments to order to avoid an accident.
Note
•  While self-learning control gradually reduces shock during normal driving, initial learning is performed to initially learn a certain amount of driving conditions.

1.  Warm-up

•  Increase the ATF temperature by leaving the vehicle idling or performing city driving. Verify that the ATF temperature is between 50—120 °C {122—248 °F}. If the ATF temperature is outside this range, work to bring it inside the range.
Caution
•  Do not raise the ATF temperature by stalling the engine.
Note
•  If the ATF temperature is not between 50—120 °C {122—248 °F}, initial learning cannot be performed.
Before learning, inspect for variable shift shock.

2.  Gear shift control learning

•  In D range, with the throttle opening between 25—30 %, drive until you reach 6th gear and a vehicle speed of 80 km/h {50 mph} or higher. Then, release the accelerator pedal and coast, and bring the vehicle to a stop in at least 60 s. Repeat this procedure 10 times.

3.  Inspect learning results

•  Verify that variable speed shock and shift shock have decreased compared to the conditions before learning.