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

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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). (See TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR INSPECTION [SJ6A-EL].) • 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. (See Initial Learning.) • Does the symptom eliminate? | Yes | Symptom troubleshooting is completed.
No | Go to the next step.
4 | • Is the line pressure normal? (See MECHANICAL SYSTEM TEST [SJ6A-EL].) | Yes | Go to the next step.
No | Repair or replace the malfunctioning part according to the inspection results.
5 | • Is the stall speed normal? (See MECHANICAL SYSTEM TEST [SJ6A-EL].) | 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: (See ON-BOARD DIAGNOSTIC TEST [L8, LF].) ― RPM ― APP ― TP ― ECT • Are the PIDs value normal? (See PCM INSPECTION [L8, LF].) | 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: (See SOLENOID VALVE INSPECTION [SJ6A-EL].) ― 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 REMOVAL/INSTALLATION [SJ6A-EL].) (See Automatic Transmission Workshop Manual [SJ6A-EL].) • If a large amount of metal specks are not found, replace the control valve body. (See CONTROL VALVE BODY REMOVAL [SJ6A-EL].) (See CONTROL VALVE BODY INSTALLATION [SJ6A-EL].)
No | • Replace the control valve body. (See CONTROL VALVE BODY REMOVAL [SJ6A-EL].) (See CONTROL VALVE BODY INSTALLATION [SJ6A-EL].)
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.