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

id0503a1804600

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 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 misadjustment • 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 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 Stall Test.) Is stall speed normal? | Yes | Go to next step.
No | Repair or replace any defective parts.
2 | • Check the value at the following PIDs using the WDS or equivalent. (See PCM INSPECTION [WITHOUT WU-TWC].) (See PCM INSPECTION [WITH WU-TWC].) - TP • Is PID value normal? | Yes | Go to next step.
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.
No | Repair open ground circuit. Reconnect PCM.
4 | • Check LPS PID value. (See PCM INSPECTION [WITHOUT WU-TWC].) (See PCM INSPECTION [WITH WU-TWC].) • Is LPS PID value normal? | Yes | Overhaul control valve body and repair or replace any defective parts. (See ATX workshop manual (FN4A-EL) [1623-10-98E].) If problem remains, overhaul transaxle and repair or replace any defective parts. (See ATX workshop manual (FN4A-EL) [1623-10-98E].)
No | Repair or replace any defective parts.
5 | • Verify test results. - If normal, return to diagnostic index to service any additional symptoms. - If malfunction remains, inspect related Service Information and perform repair or diagnosis. • If vehicle repaired, troubleshooting completed. • If vehicle not repaired or additional diagnostic information not available, replace PCM.