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NO.18 EXCESSIVE SHIFT SHOCK IS FELT WHEN UPSHIFTING AND DOWNSHIFTING [FN4A-EL]

BME050301030222

18 | Excessive shift shock is felt when upshifting and downshifting
DESCRIPTION | • Excessive shift shock is felt when depressing the accelerator pedal at upshifting. During cruising, excessive shift shock is felt when depressing the accelerator pedal at downshifting.
POSSIBLE CAUSE | • Shift shock may worsen when the fail-safe is operating. The shift shock has worsened if the TP sensor, input/turbine speed sensor, or vehicle speed sensor signal malfunctions. 1. Clutch slippage, burnt (Forward clutch, 2-4 brake band, 3-4 clutch)

  • Line pressure low, high
  • Shift solenoid D malfunction
  • Shift solenoid E malfunction
  • Shift solenoid A malfunction
  • Shift solenoid B malfunction
  • Shift solenoid C malfunction
  • Pressure control solenoid malfunction
  • Accelerator cable mis-adjustment
  • Control valve body malfunction
  • Body GND malfunction

2. Signal malfunction

  • Transaxle temperature sensor malfunction
  • Vehicle speed sensor malfunction
  • Sensor GND malfunction
  • TP sensor malfunction
  • Input/turbine speed sensor malfunction

3. Poor hydraulic operation (Malfunction in range change)

  • Pressure switch malfunction
  • Forward accumulator malfunction
  • Servo apply accumulator malfunction

  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 | Perform the stall test. (See Stall Test.) Is the stall speed normal? | Yes | Go to the next step.
No | Repair or replace any malfunctioning parts.
2 | Inspect the value at the following PCM PID using the WDS or equivalent. (See PCM INSPECTION [L3].) • TP V Is the PID value normal? | Yes | Go to the next step.
No | Repair or replace any malfunctioning parts.
3 | Disconnect the PCM connector. Is the resistance between the ground terminal at the PCM connector and the body ground less than 5.0 ohms? | Yes | Go to the next step.
No | Repair the open ground circuit. Reconnect the PCM.
4 | Inspect the LPS PID value using the WDS or equivalent. Is the LPS PID value normal? (See PCM INSPECTION [L3].) | Yes | Overhaul the control valve body and repair or replace any malfunctioning parts. (See ATX workshop manual (FN4A-EL).) If any problem remains, overhaul the transaxle and repair or replace any malfunctioning parts. (See ATX workshop manual (FN4A-EL).)
No | Repair or replace any malfunctioning parts.