NO.19 SHIFT CONCERN: SOFT/SLIPPING 4–3 SHIFT (AUTOMATIC)[LA4AX-EL (CD4E)]

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19

Shift concern: soft/slipping 4–3 shift (automatic)

POSSIBLE CAUSE

•  Powertrain control system malfunction

•  Control valve body malfunction

•  2/4 band and servo component malfunction

•  Direct clutch component malfunction

•  Forward/coasting clutch component malfunction

•  Transaxle case malfunction

19	Shift concern: soft/slipping 4–3 shift (automatic)
POSSIBLE CAUSE	• Powertrain control system malfunction • Control valve body malfunction • 2/4 band and servo component malfunction • Direct clutch component malfunction • Forward/coasting clutch component malfunction • Transaxle case malfunction

Diagnostic procedure

STEP	INSPECTION		ACTION
1	Powertrain control system • Are there any malfunctions with the following? ― Electrical input/output ― Vehicle wiring harness ― PCM ― Electrical pressure control (EPC) solenoid ― Vehicle speedometer sensor (VSS) ― Mass air flow (MAF) sensor ― Throttle position (TP) sensor	Yes	Perform OBD test Perform DTC troubleshooting (See AUTOMATIC TRANSAXLE ON-BOARD DIAGNOSTIC FUNCTION[LA4AX-EL (CD4E)].)
1		No	Go to the next step
2	Control valve body • Do any of the following malfunctions exist? ― Bolts are not tightened to the specification ― Gasket leaks ― Servo release shutter valve, main regulator valve are stuck, damaged, or misassembled ― Hydraulic passages are damaged ― Pressure tap plate/gasket leaks, or damaged ― Separator plates are damaged or blocked	Yes	Service if necessary
2		No	Go to the next step
3	2/4 band and servo component • Do any of the following malfunctions exist? ― 2/4 band and/or reverse clutch drum component are damaged, worn, or misassembled ― Servo return spring is broken ― Servo rod is damaged ― Piston seal is damaged	Yes	Service if necessary
3		No	Go to the next step
4	Direct clutch component • Do any of the following malfunctions exist? ― Seals are damaged or missing ― Piston is damaged ― Inspect the check ball for damage, loss, or leakage ― Return spring is damaged ― Friction elements are damaged	Yes	Service if necessary
4		No	Go to the next step
5	Forward/coasting clutch component • Do any of the following malfunctions exist? ― Seals are damaged or missing ― Piston is damaged ― Friction elements are worn or damaged ― The ball is not functioning ― Forward clutch piston and return spring are damaged	Yes	Service if necessary
5		No	Go to the next step
6	Transaxle case • Do any of the following malfunctions exists? ― Porosity/cross leaks in servo apply, servo release, direct clutch circuits	Yes	Service if necessary
6		No	The malfunction is not in the automatic transaxle Go to the engine symptom troubleshooting (See ENGINE SYMPTOM TROUBLESHOOTING[AJ (3.0L Duratec)].)
7	• 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.