Inspection Procedure 13: Gear shift does not occur with 3rd <=> 4th




COMMENTS ON TROUBLE SYMPTOM


When the gear does not shift from 3rd to 4th and from 4th to 3rd, the cause is probably a malfunction of inhibitor switch system, C3 pressure control solenoid (SL3) system, C4 pressure control solenoid (SL4) system, or valve body.

PROBABLE CAUSES




DIAGNOSIS PROCEDURE


STEP 1. M.U.T.-III data list



  • Refer to Data List Reference Table .

    1. Item 24: Inhibitor switch P
    2. Item 25: Inhibitor switch R
    3. Item 26: Inhibitor switch N
    4. Item 27: Inhibitor switch D

Q. Is the check result normal?

Go to Step 3.
Go to Step 2.

STEP 2. Inhibitor switch continuity check


Refer to .

Q. Is the check result normal?

Go to Step 3.
Replace the inhibitor switch.

STEP 3. M.U.T.-III actuator test


Item 7: Linear solenoid 3
Item 8: Linear solenoid 4
OK: Operating sound can be heard.

Q. Is the check result normal?

Go to Step 4.
Repair the C3 pressure control solenoid (SL3) system or C4 pressure control solenoid (SL4) system.

STEP 4. Check of inhibitor switch and transmission control cable


Check the installation status of inhibitor switch and transmission control cable.

Q. Is the check result normal?

Go to Step 5.
Adjust the inhibitor switch and the transmission control cable. (Refer to .)

STEP 5. Retest the system


If the trouble symptom is not solved, replace the valve body. Then, check the trouble symptom again.

Q. Is the trouble symptom reproduced?

Go to Step 6.
This diagnosis is complete.

STEP 6. A/T-ECU replacement


(1)Replace the A/T-ECU.
(2)Test drive the vehicle.
(3)Verify that the condition described by the customer exists.

Q. Is the trouble symptom reproduced?

Check the clutches and brakes for damage, and replace if necessary. (It is highly possible that the clutch C3 and clutch C4 that operate at shift change between 3rd and 4th are damaged.)
This diagnosis is complete.





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