NO.18 EXCESSIVE SHIFT SHOCK IS FELT WHEN UPSHIFTING AND DOWNSHIFTING [GF4AX-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 felt when depressing accelerator pedal at downshifting.
POSSIBLE CAUSE	• Shift shock may worsen when fail-safe is operating. The shift shock increases if TP sensor, input/turbine speed sensor, or VSS signal malfunctions. 1. Clutch slippage, burnt (2-4 brake band, 3-4 clutch) • Line pressure low, high • TP sensor malfunction • VSS malfunction • Input/turbine speed sensor malfunction • TFT sensor malfunction • Shift solenoid A, B, or C malfunction • TCC solenoid valve malfunction 3-2 timing solenoid valve malfunction • Throttle cable mis-adjustment • Body GND and sensor GND malfunction • Control valve body malfunction 2. Poor hydraulic operation (Malfunction in range change) Note • Before following the troubleshooting steps, make sure that the Automatic Transaxle On-Board Diagnostic and Automatic Transaxle Basic Inspection are conducted.


STEP	INSPECTION		ACTION
1	Is the line pressure normal? (See Line Pressure Test.)	Yes	Go to the next step.
1	Is the line pressure normal? (See Line Pressure Test.)	No	Repair or replace any malfunctioning parts according to the inspection results.
2	Is the stall speed normal? (See Stall Speed Test.)	Yes	Go to the next step.
2	Is the stall speed normal? (See Stall Speed Test.)	No	Repair or replace any malfunctioning parts according to the inspection results.
3	Connect the WDS or equivalent to DLC-2. Access TFT and TFTV PIDs. Drive the vehicle while monitoring PIDs. (See PCM INSPECTION [L3 R.H.D.].) Are the PIDs within the specification?	Yes	Go to the next step.
3		No	Inspect the TFT sensor and related wiring harness: for intermittent open/short circuit during vibration.
4	Connect the WDS or equivalent to DLC-2. Access TRD, TP, TSS and VSS PIDs. Drive the vehicle in D range while monitoring PIDs (O/D OFF switch off). (See PCM INSPECTION [L3 R.H.D.].) Are the PIDs within the specification?	Yes	Go to the next step.
4		No	TRD PID: • Inspect the TR switch and related wiring harness: for intermittent open/short circuit during vibration. TP PID: • Inspect if output signal from the TP sensor changes smoothly. TSS PID: • Inspect the input/turbine speed sensor and related wiring harness: for intermittent open/short circuit during vibration. VSS PID: • Inspect for intermittent open circuit of the VSS and related wiring harness.
5	Turn the ignition switch to the ON position. Connect the WDS or equivalent to DLC-2. Simulate 3-2SOL PID for ON. Is the 3-2 timing solenoid operating sound heard?	Yes	Replace the control valve body and repair or replace any malfunctioning parts. (See ATX Workshop Manual (GF4AX-EL)) If any problem remains, replace the transaxle and repair or replace any malfunctioning parts. (See ATX Workshop Manual (GF4AX-EL))
5		No	Inspect connection of 3-2 timing solenoid valve terminal on the ATX for bent terminals, damage, corrosion or looseness. Is the 3-2 timing solenoid valve stuck. (See Operating Inspection (On-vehicle Inspection).) If the shift solenoids are normal, inspect for open or short circuit between the PCM terminal 39 and the 3-2 timing solenoid valve terminal E.
6	• 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.