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

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 (See AUTOMATIC TRANSAXLE ON-BOARD DIAGNOSTIC FUNCTION[LA4AX-EL (CD4E)].)
1		No	Go to the next step
2	Improper pressures • Is the line pressure low? (See MECHANICAL SYSTEM TEST[LA4AX-EL (CD4E)].)	Yes	Go to step 4 to check the following components Control valve body, oil pump, reverse clutch component, low/reverse clutch component
2		No	Go to the next step
3	Internal or external shift linkages • Do any of the following malfunctions exist? ― Damage ― Misadjustment	Yes	Service if necessary
3		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
4		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
5		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
6		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
7		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
8		No	Go to the next step
9	Reverse/fourth (REV/4GR) carrier component • Is there any damage?	Yes	Service if necessary
9		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
10		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 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.