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


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, TP 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 cable mis-adjustment • Control valve body malfunction • Body GND malfunction 2. Signal malfunction • Transaxle temperature sensor malfunction • Vehicle speed sensor malfunction • Sensor GND malfunction • Accelerator pedal position sensor malfunction • TP 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.


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