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NO.17 EXCESSIVE SHIFT SHOCK FROM N TO D OR N TO R POSITION/RANGE [FN4A-EL]

id0503a1802200

17 | Excessive shift shock from N to D or N to R position/range
DESCRIPTION | • Strong shock felt when shifting from N to D or N to R position/range.
POSSIBLE CAUSE | • Shift shock may worsen when the fail-safe is operating. If no DTC is output, the shift shock may worsen due to poor operation of the control valve body or sticking of the clutch. 1. Clutch burned (N→D: Forward clutch, N→R: Reverse clutch or low and reverse brake) • Line pressure low, high • TP sensor malfunction • Vehicle speed sensor malfunction • Input/turbine speed sensor malfunction • Shift solenoid B malfunction • Shift solenoid D malfunction • Shift solenoid A malfunction • Shift solenoid C malfunction • Pressure control solenoid malfunction • Accelerator cable misadjustment • Control valve body malfunction • Sensor GND malfunction • Body GND malfunction 2. Poor hydraulic operation (Malfunction in range change) • Forward accumulator malfunction • Servo apply accumulator malfunction • Pressure switch malfunction 3. Idle speed high 4. Poor tightening torque of engine mount, exhaust mount 5. Poor operation of mechanical pressure • Selector lever position disparity 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 | • Does shift shock occur only when engine is cold? | Yes | Go to next step.
No | Go to Step 3.
2 | • Disconnect PCM. • Is resistance between ground terminal at PCM connector and body ground less than 5.0 ohms? | Yes | 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 • TFT • TFTV Repair or replace any defective parts.
No | Repair open ground circuit. Reconnect PCM.
3 | • Perform the stall test. (See Stall Test.) • Is stall speed normal? | Yes | Go to next step.
No | Go to Step 5.
4 | • Check the value at the following PIDs using the WDS or equivalent. (See PCM INSPECTION [WITHOUT WU-TWC].) (See PCM INSPECTION [WITH WU-TWC].) - TR • Is 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 | • Check the value at the following PID 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.
6 | • 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.
7 | • 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.