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

id050301804600

18

Excessive shift shock is felt when upshifting and downshifting

DESCRIPTION

•  Excessive shift shock felt when depressing accelerator pedal to accelerate at upshifting. During cruising, excessive shift shock is felt when depressing accelerator pedal at downshifting.

POSSIBLE CAUSE

•  Shift shock may worsen when fail-safe is operating. The shift shock has worsened if the accelerator pedal position sensor, input/turbine speed sensor, or vehicle speed sensor signal malfunctions.

1.  Clutch slipped, burned (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 pedal position sensor malfunction

•  Control valve body malfunction

•  Body GND malfunction

2.  Signal malfunction

•  TFT sensor malfunction

•  Vehicle speed sensor malfunction

•  Sensor GND malfunction

•  Accelerator pedal position sensor malfunction

•  Input/turbine speed sensor malfunction

3.  Poor hydraulic operation (Malfunction in range change)

•  Forward accumulator malfunction

•  Servo apply accumulator malfunction

Note

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

Diagnostic procedure

STEP	INSPECTION		ACTION
1	Perform the stall test. (See MECHANICAL SYSTEM TEST [FN4A-EL].) Is stall speed okay?	Yes	Go to next step.
1		No	Repair or replace any defective parts.
2	Check the value at the following PIDs using the M-MDS. (See PCM INSPECTION [ZJ, ZY].) • APP Are PID values okay?	Yes	Go to next step.
2		No	Repair or replace any defective parts.
3	Disconnect PCM. Is resistance between GND terminal at PCM connector and body GND less than 5.0 ohms?	Yes	Go to next step.
3		No	Repair open GND circuit. Reconnect PCM.
4	Check LPS PID value. Is LPS PID value okay? (See PCM INSPECTION [ZJ, ZY].)	Yes	Overhaul control valve body and repair or replace any defective parts. If problem remains, overhaul transaxle and repair or replace any defective parts.
4		No	Repair or replace any defective parts.
5	• Verify test results. ― If okay, return to diagnostic index to service any additional symptoms. ― If malfunction remains, inspect related Service informations and perform repair or diagnosis. • If vehicle not repaired, trouble shooting completed. • If vehicle not repaired or additional diagnostic information not available, replace PCM.