NO.15 SHIFT CONCERN: NO 3-4 SHIFT [LA4AX-EL (CD4E)]

id0503a2804300

15

Shift concern: no 3-4 shift

POSSIBLE CAUSE

• Powertrain control system malfunction
• Improper pressure
• Control valve body malfunction
2/4 band and servo component malfunction
• Coasting clutch component malfunction
• Forward OWC component malfunction
• Transaxle case malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
Powertrain control system
• Do any of the following malfunctions exist?
- Electrical input/output
- Vehicle wiring harness
- PCM
- Shift solenoid No.1 (SS1), Shift solenoid No.2 (SS2)
- Transaxle range (TR) switch
Yes
Perform OBD test
Perform DTC troubleshooting
No
Go to the next step
2
Improper pressure
• Do any of the following malfunctions exist?
- High line pressure
- Low line pressure
(See Line Pressure Test.)
Yes
Go to the next step
No
Go to step 4
3
Control valve body
• Do any of the following malfunctions exist?
- Bolts are not tightened to the specification
- Gasket leaks
- 3-4 Shift Valve, main regulator valve are stuck, damaged, or misassembled
- SS1, SS2 malfunction (Also no first gear)
- Separator plates are damaged, or orifice is blocked
Yes
Service if necessary
No
Go to the next step
4
2/4 band and servo component
(No second gear engagement also)
• Do any of the following malfunctions exist?
- 2/4 band is damaged or worn
- Servo rod or rod bore is damaged
- Servo piston or cover is damaged or leaking
- Springs are damaged
Yes
Service if necessary
No
Go to the next step
5
Coasting clutch component
• Do any of the following malfunctions exist?
- Seals are damaged or missing
- Piston is damaged
- Friction is severely damaged or worn
- Check ball is severely damaged
Yes
Service if necessary
No
Go to the next step
6
Forward OWC component
• Is there any damage?
Yes
Service if necessary
No
Go to the next step
7
Transaxle case
(No second gear engagement also)
• Do any of the following problems exist?
- Band anchor is damaged
- Leakage in the servo apply and servo release
Yes
Service if necessary
No
Go to the next step
8
• Verify the test results.
- If normal, return to the diagnostic index to service any additional symptoms.
- If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair 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.