6

Low maximum speed and poor acceleration

DESCRIPTION

• Vehicle acceleration is poor at start.

• Delayed acceleration when accelerator pedal is depressed while driving.

POSSIBLE CAUSE

• If the clutch is stuck or does not stay in 4GR, malfunction is in engine circuit.

• Clutch slippage, burnt (C1 clutch, C2 clutch, C3 clutch, B1 brake, B2 brake, B3 brake, B4 brake)

• Line pressure low

• Line pressure control solenoid malfunction

• Control valve body malfunction

• Transmission fixed in 4GR (Operation of fail-safe function)

• Short or open circuit in wiring harness

• Poor connection of connector

• Malfunction of electronic parts of output and input system

• Insufficient starting torque (Suspected when in-gear, shift control and engine circuit are normal)

• Torque converter malfunction (Poor operation, stuck)

• Engine output low

STEP

INSPECTION

ACTION

1

• With the ignition switch at the ON position.

• Does the gear position indication correspond to the selector lever position?

Yes

Go to the next step.

No

Perform the symptom troubleshooting “NO.27 GEAR POSITION INDICATION ILLUMINATES IN D POSITION”, or “NO.28 GEAR POSITION INDICATION DOES NOT ILLUMINATE IN M POSITION”.

(See NO.27 GEAR POSITION INDICATION ILLUMINATES IN D POSITION [SJ6A-EL].)

(See NO.28 GEAR POSITION INDICATION DOES NOT ILLUMINATE IN M POSITION [SJ6A-EL].)

2

• Perform the symptom troubleshooting “NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE”.

  (See NO.12 LACK/LOSS OF POWER-ACCELERATION/CRUISE [SKYACTIV-G 2.0].)

• Does the engine control system normal?

Yes

Go to the next step.

No

Repair or replace the malfunctioning part according to the inspection results.

3

• Stop the engine.

• Inspect line pressure control solenoid.

  (See SOLENOID VALVE INSPECTION [SJ6A-EL].)

• Is the line pressure control solenoid normal?

Yes

Go to the next step.

No

Inspect the coupler component.

• If normal, replace the control valve body.

  (See CONTROL VALVE BODY REMOVAL [SJ6A-EL].)

  (See CONTROL VALVE BODY INSTALLATION [SJ6A-EL].)

4

• Inspect the ATF condition.

  (See AUTOMATIC TRANSMISSION FLUID (ATF) INSPECTION [SJ6A-EL].)

• Are there any metal specks found in ATF?

Yes

• 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 torque converter.

(See TORQUE CONVERTER REMOVAL/INSTALLATION [SJ6A-EL].)

5

• Verify test results.

• If normal, return to the diagnostic index to service any additional symptoms.

• If malfunction remains, inspect the related Service Bulletins and/or On-line Repair 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].)