If shift shock when driving are due to upshifting or downshifting and the transmission
speed become higher than the engine speed, the cause is probably abnormal line pressure or a
malfunction of a solenoid valve, oil pump, valve body or of a brake or clutch.
PROBABLE CAUSES
Malfunction of each solenoid valve
Abnormal line pressure
Malfunction of valve body
Malfunction of oil pump
Malfunction of each brake or each clutch
Malfunction of the A/T-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III actuator test
Item 01: Low-reverse solenoid valve
Item 02: Underdrive solenoid valve
Item 03: Second solenoid valve
Item 04: Overdrive solenoid valve
OK: Operating sound can be heard.
Q.
Is the check result normal?
Go to Step 2.
Replace the defective solenoid valve.
STEP 2. M.U.T.-III data list
Item 11: Shift position (Refer to data list reference table ).
Item 12, 13, 14, 15: Each solenoid valve duty ratio (Refer to data list reference
table ).
Q.
Is the check result normal?
Go to Step 3.
Replace the A/T-ECU.
STEP 3. Hydraulic pressure test
Check all hydraulic pressures within the standard value.
OK: Refer to .
Q.
Is the check result normal?
Go to Step 6.
Go to Step 4.
STEP 4. Line pressure adjustment
(1)Adjust the line pressure (Refer to ).
(2)Test drive the vehicle.
(3)Verify that the condition described by the customer exists.
Q.
Does a malfunction take place again?
Go to Step 5.
The inspection is complete.
STEP 5. Valve body disassembly clean and assembly
(1)Check the bolts for looseness and the O-ring, solenoid valve and valve body for
damage. Replace the valve body assembly if the damages are thought to be irreparable.
(2)Test drive the vehicle.
(3)Verify that the condition described by the customer exists.
Q.
Does a malfunction take place again?
Check the oil pump for incorrect installation, damage and etc., and replace the
oil pump assembly if necessary (The oil pump cannot be disassembled).
The inspection is complete.
STEP 6. Each clutch and brake check
Check the facing for seizure and the piston seal ring for damage and interference with
the retainer.