Inspection Procedure 9
INSPECTION PROCEDURE 9: Shift Shock and SlippingCOMMENT
If shift shock when driving is due to upshifting or downshifting and the transaxle speed become higher than the engine speed, the cause is probably abnormal line pressure or a malfunction of a solenoid valve, oil pump, valve body or of a brake or clutch.
TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CONDITION:)
^ Abnormal line pressure
^ Malfunction of each solenoid valve
^ Malfunction of the oil pump
^ Malfunction of the valve body
^ Malfunction of each brake or each clutch
^ Malfunction of the PCM
DIAGNOSIS
Required Special Tool:
^ MB991958: Scan Tool (M.U.T-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
STEP 1. Using scan tool MB991958, check actuator test.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
(1) Connect scan tool MB991958 to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool MB991958 to actuator test mode for following items.
a. Item 01: Low-reverse solenoid valve
b. Item 02: Underdrive solenoid valve
c. Item 03: Second solenoid valve
d. Item 04: Overdrive solenoid valve
^ An audible clicking or buzzing should be heard when the solenoid valves are energized.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Are the solenoid valves operating properly?
YES: Go to Step 2.
NO: Repair or replace the solenoid valves. Then confirm that the symptom is eliminated.
STEP 2. Check the hydraulic pressure.
(1) Measure the hydraulic pressure of each element. Check if each hydraulic pressure is within the standard value. Refer to Hydraulic Pressure Test. Hydraulic Pressure Tests
(2) If some elements pressure are within the standard value and some are not, recheck the symptom.
Q: Are all hydraulic pressures within the standard value?
YES: Go to Step 6.
NO: Go to Step 3.
STEP 3. Adjust the line pressure.
Adjust the line pressure. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 4.
STEP 4. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and the valve body for damage. Repair or replace the faulty parts.
Replace the valve body assembly if the damages are thought to be irreparable. Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 5.
STEP 5. Check the oil pump.
(1) Remove the transaxle assembly.
(2) Check the oil pump (incorrect installation, damage and etc.) and replace the oil pump assembly if necessary (The oil pump cannot be disassembly). Then check the symptom.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 7.
STEP 6. Check each brake and clutch.
(1) Remove the transaxle.
(2) Check the facing for seizure and piston seal ring for damage and interference with retainer. Repair or replace the faulty parts. Then Retest the system.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Go to Step 7.
STEP 7. Replace the PCM.
Q: Is the symptom eliminated?
YES: The procedure is complete.
NO: Start over at Step 1.