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NO.14 ENGINE FLARES UP OR SLIPS WHEN UPSHIFTING OR DOWNSHIFTING [JA5A-EL]

BME050301030250

14 | Engine flares up or slips when upshifting or downshifting
DESCRIPTION | • When the accelerator pedal is depressed for driveway, engine speed increases but vehicle speed increase slowly. • When the accelerator pedal is depressed while driving, engine speed increases but vehicle does not.
POSSIBLE CAUSE | • There is clutch slip because clutch is stuck or line pressure is low.

  1. Clutch stuck, slippage

  • Line pressure low
  • Incorrect throttle position signal
  • VSS malfunction
  • Input/turbine speed sensor malfunction
  • Sensor GND malfunction
  • Shift solenoid A, B, or C malfunction
  • TCC solenoid valve malfunction
  • Body GND malfunction
  • Throttle cable mis-adjustment
  • Control valve body malfunction

  2. Poor operation of mechanical pressure

  • Selector lever position disparity
  • TR switch position disparity

  Note

  • Before following the troubleshooting steps, make sure that the Automatic Transaxle On-Board Diagnostic and Automatic Transaxle Basic Inspection are conducted.

Diagnostic procedure

STEP | INSPECTION | ACTION
--- | --- | ---
1 | Is the line pressure normal? (See Line Pressure Test.) | Yes | Go to the next step.
No | Repair or replace any malfunctioning parts according to the inspection results.
2 | Is shift point normal? (See ROAD TEST [JA5A-EL].) | Yes | Go to the next step.
No | Go to No.9 "ABNORMAL SHIFTING".
3 | Stop the engine. Inspect the shift solenoid A, B, or C circuit. Are they normal? | Yes | Overhaul the control valve body and repair or replace any malfunctioning parts. (See ATX Workshop Manual.) If any problem remains, replace or overhaul the transaxle and repair or replace any malfunctioning parts. (See ATX Workshop Manual.)
No | Inspect for stuck shift solenoid. (See SOLENOID VALVE INSPECTION [JA5A-EL].)
4 | • Verify the test results.

  - If normal, return to the diagnostic index to service any additional symptoms.
  - If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis.

  • If the vehicle is repaired, troubleshooting is completed.
  • If the vehicle is not repaired or additional diagnostic information is not available, replace the TCM.