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 is felt when depressing the accelerator pedal to accelerate 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 APP sensor, input/turbine speed sensor, or ABS wheel-speed sensor signal malfunctions.

1.  Clutch slipped, burnt (Forward clutch, 2–4 brake band, 3–4 clutch)

•  Line pressure low, high

•  Shift solenoid A malfunction

•  Shift solenoid B malfunction

•  Shift solenoid C malfunction

•  Shift solenoid D malfunction

•  Shift solenoid E malfunction

•  Pressure control solenoid malfunction

•  Control valve body malfunction

•  APP sensor malfunction

•  Body GND malfunction

2.  Signal malfunction

•  APP sensor malfunction

•  Input/turbine speed sensor malfunction

•  ABS wheel-speed sensor malfunction

•  TFT sensor malfunction

•  Sensor GND malfunction

3.  Poor hydraulic operation (Malfunction in position 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. (See ON-BOARD DIAGNOSTIC SYSTEM DTC INSPECTION [FN4A-EL].) (See BASIC INSPECTION [FN4A-EL].)

Diagnostic procedure

STEP	INSPECTION		ACTION
1	Perform the stall test. (See MECHANICAL SYSTEM TEST [FN4A-EL].) Is the stall speed normal?	Yes	Go to the next step.
1		No	Repair or replace any malfunctioning parts.
2	Inspect the APP PID value using the M-MDS. (See PCM INSPECTION [MZR 1.6].) Is the PID value normal?	Yes	Go to the next step.
2		No	Repair or replace any malfunctioning parts.
3	Disconnect the PCM connector. Measure the resistance between ground terminal at the PCM connector and body ground. Is the resistance less than 5.0 ohms?	Yes	Go to the next step.
3		No	Repair or replace the wiring harness for a possible open circuit.
4	Inspect the LPS PID value using the M-MDS. (See ON-BOARD DIAGNOSTIC SYSTEM PID/DATA MONITOR INSPECTION [FN4A-EL].) Is the PID value normal?	Yes	Overhaul the control valve body and repair or replace any malfunctioning parts. If any problem remains: • Overhaul the transaxle and repair or replace any malfunctioning parts.
4		No	Repair or replace any malfunctioning parts.
5	• Verify the test results. ― If normal, return to the diagnostic index to service any additional symptoms. ― If the malfunction remains, inspect the related Service 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 PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.6].)