NO.2 NO REVERSE ENGAGEMENT (NO MOVEMENT) [LA4AX-EL (CD4E)]

id0503a2804900

2

No reverse engagement (no movement)

POSSIBLE CAUSE

• Powertrain control system malfunction
• Improper pressures
• Internal or external shift linkage malfunction
• Control valve body malfunction
• Oil pump malfunction
• Reverse clutch component malfunction
• Low/reverse clutch component malfunction
• Forward/coasting/direct (F/C/D) clutch cylinder component malfunction
• Transaxle case malfunction
• Reverse/fourth gear (REV/4GR) carrier component malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1
Powertrain control system
• Are there any problems with the following?
- Electrical input/output
- Vehicle wiring harness
- PCM
- Shift solenoid No.1 (SS1) (ON)
- Transaxle range (TR) switch
Yes
Run OBD tests
Perform DTC troubleshooting
No
Go to the next step
2
Improper pressures
• Is the line pressure low?
Yes
Go to step 4 to check the following components
Control valve body, oil pump, reverse clutch component, low/reverse clutch component
No
Go to the next step
3
Internal or external shift linkages
• Do any of the following malfunctions exist?
- Damage
- Misadjustment
(See SELECTOR LEVER REMOVAL/INSTALLATION.)
Yes
Service if necessary
No
Go to step 9
4
Control valve body
• Do any of the following malfunctions exist?
- Bolts are not tightened to the specification
- Gasket is damaged
- 1-2 shift valve, SS1, main regulator valve, low/reverse modulator valve, low/reverse accumulator piston, pressure tap plate are damaged, missing, stuck, or misassembled
- Separator plates are damaged
- Hydraulic passages are damaged
Yes
Service if necessary
No
Go to the next step
5
Oil pump
• Do any of the following malfunctions exist?
- Bolts are not tightened to the specification
- Gasket is damaged
- Porosity/cross leaks and/or the ball plug is missing, leaking, or the hole is plugged
- Oil pump support seal rings, #6 and #7, are damaged
Yes
Service if necessary
No
Go to the next step
6
Reverse clutch component
• Do any of the following malfunctions exist?
- Seals or piston are damaged
- Ball check valve is damaged
- Friction elements worn, severely damaged, or misassembled
- Piston return spring damaged
- Reverse clutch hub to F/C/D clutch hub splines are damaged
Yes
Service if necessary
No
Go to the next step
7
Low/reverse clutch component
• Do any of the following malfunctions exist?
- Seals or piston are damaged
- Friction elements are worn or severely damaged
- Piston return spring is damaged
- Wave spring is missing
- Piston bore is damaged
Yes
Service if necessary
No
Go to the next step
8
Forward/coasting/direct clutch cylinder
• Are any of the reverse seal rings damaged, missing, or misassembled?
Yes
Service if necessary
No
Go to the next step
9
Reverse/fourth (REV/4GR) carrier component
• Is there any damage?
Yes
Service if necessary
No
Go to the next step
10
Transaxle case
• Is there any severe cross leakage from the reverse clutch to low/reverse clutch feeds?
Yes
Service if necessary
No
The problem is resolved
11
• 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.