A/T Does Not Shift: 4TH Gear->3RD Gear

A/T Does Not Shift: 4th gear -> 3rd gear

SYMPTOM: When shifted from 4M to 3M position in manual mode, does not downshift from 4th to 3rd gear.

DIAGNOSTIC PROCEDURE
1. CHECK A/T FLUID LEVEL
Check the A/T fluid level. Refer to "A/T FLUID CHECK".
OK or NG
OK >>GO TO 2.
NG >>Refill ATF.

2. CHECK SELF-DIAGNOSTIC RESULTS
Perform self-diagnosis.
Is any malfunction detected by self-diagnostic?
YES >>Check the malfunctioning system.
NO >>GO TO 3.

3. DETECT MALFUNCTIONING ITEM
1. Control valve assembly. Refer to "Control Valve Assembly".
2. Disassemble A/T. Refer to "DISASSEMBLY".
3. Check the following items:
^ U/D clutch. Refer to "DISASSEMBLY".
^ U/D brake. Refer to "DISASSEMBLY".
OK or NG
OK >>GO TO 4.
NG >>Repair or replace damaged parts.

4. CHECK TCM
1. Check TCM input/output signal. Refer to "TCM Input/Output Signal Reference Values". Pinout Values and Diagnostic Parameters
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK >>GO TO 5.
NG >>Repair or replace damaged parts.

5. CHECK SYMPTOM
Check again.
OK or NG
OK >> INSPECTION END
NG >>Repair or replace damaged parts.