NO.18 EXCESSIVE SHIFT SHOCK IS FELT WHEN UPSHIFTING AND DOWNSHIFTING[GF4AX-EL]

id0503a3804600

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
•  APP 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.

Diagnostic procedure

STEP

INSPECTION

ACTION
1
Is the line pressure normal?
(See MECHANICAL SYSTEM TEST[GF4AX-EL].)
Yes
Go to the next step.
No
Repair or replace any malfunctioning parts according to the inspection results.
2
Is the stall speed normal?
(See MECHANICAL SYSTEM TEST[GF4AX-EL].)
Yes
Go to the next step.
No
Repair or replace any malfunctioning parts according to the inspection results.
3
Connect the M-MDS to DLC-2.
Access TFT and TFTV PIDs.
Drive the vehicle while monitoring PIDs.
(See PCM INSPECTION[L3].)
Are the PIDs within the specification?
Yes
Go to the next step.
No
Inspect the TFT sensor and related wiring harness: for intermittent open/short circuit during vibration.
4
Connect the M-MDS to DLC-2.
Access TRD, APP1, APP2, TSS and VSS PIDs.
Drive the vehicle in D range while monitoring PIDs (O/D OFF switch off).
(See PCM INSPECTION[L3].)
Are the PIDs within the specification?
Yes
Go to the next step.
No
TRD PID:
•  Inspect the TR switch and related wiring harness: for intermittent open/short circuit during vibration.
APP1, APP2 PID:
•  Inspect if output signal from the APP 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 M-MDS 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))
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 SOLENOID VALVE INSPECTION[GF4AX-EL].)
If the shift solenoids are normal, inspect for open or short circuit between the PCM terminal 1C 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.