NO.21 SHIFT CONCERN: SOFT/SLIPPING 2-1 SHIFT (AUTOMATIC OR KICKDOWN) [LA4AX-EL (CD4E)]


id0503a2805200

21

Shift concern: soft/slipping 2-1 shift (automatic or kickdown)

POSSIBLE CAUSE

• Powertrain control system malfunction
• Oil pump malfunction
2/4 band and servo component malfunction
• Forward clutch component malfunction
• Low one-way clutch (OWC) component 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
- Transaxle fluid temperature (TFT) sensor
- Throttle position (TP) sensor
- Mass air flow (MAF) sensor
Yes
Perform OBD test
Perform DTC troubleshooting
No
Go to the next step
2
Oil pump
• Do any of the following malfunctions exist?
- Gaskets are damaged
- Porosity/cross leaks
- Pump support seals #3 and 4 are leaking, misassembled, or damaged
Yes
Service if necessary
No
Go to the next step
3
2/4 band and servo component
• Do either of the following malfunctions exist?
- Piston is damaged
- Return spring is damaged
Yes
Service if necessary
No
Go to the next step
4
Forward clutch component
• Do either of the following malfunctions exist?
- Piston or seals are damaged
- Friction elements are damaged
Yes
Service if necessary
No
Go to the next step
5
Low OWC component
• Is the low OWC damaged or not holding?
Yes
Service if necessary
No
The malfunction is not in the automatic transaxle
Go to the engine symptom troubleshooting
6
• 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.