Inspection Procedure 6
INSPECTION PROCEDURE 6: Shift Shock when Shifting from "N" to "D" and Long DelayCOMMENT
If abnormal shock or delay of two seconds or more occurs when the selector lever is shifted from "N" to "D" range while the engine is idling, the cause is probably abnormal underdrive clutch pressure or a malfunction of the underdrive clutch, valve body or throttle position sensor.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
^ Abnormal underdrive clutch pressure
^ Malfunction of the underdrive solenoid valve
^ Malfunction of the underdrive clutch
^ Malfunction of the valve body
^ Malfunction of the throttle position sensor
^ Malfunction of the PCM
DIAGNOSIS
Required Special Tool: MB991502: Scan Tool (MUT-II)
STEP 1. Using scan tool MB991502, check actuator test item 02: Underdrive Solenoid Valve.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Set scan tool MB991502 to actuator test mode for item 02: Underdrive Solenoid Valve.
^ An operation sound should be heard from solenoid valve when solenoid valve is operated.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the solenoid valve operating properly?
YES: Go to Step 2.
NO: Repair or replace the underdrive solenoid valve. Then confirm that the symptom is eliminated.
STEP 2. Check when shift shock occurs.
Q: When does the shift shock occur? When engaging from "N" to "D": Go to Step 3. When the vehicle starts moving: Go to Step 6.
STEP 3. Check the hydraulic pressure (for underdrive clutch).
Measure the hydraulic pressure for underdrive clutch when the selector lever is shifted from "N" to "D" range. Check if the hydraulic pressure is within the standard value.
Q: Is the hydraulic pressure within the standard value?
YES: Go to Step 4.
NO: Go to Step 8.
STEP 4. Check the underdrive clutch system.
1. Remove the valve body cover and valve body.
2. Blow 108 kPa (15 psi) compressed air into the underdrive clutch oil orifice of the transaxle case, and check if the underdrive clutch piston moves and air pressure is maintained in that condition.
Q: Is the air pressure maintained?
YES: Go to Step 8.
NO: Go to Step 5.
STEP 5. Check the underdrive clutch.
1. Remove the transaxle assembly.
2. Check the facing for seizure and the piston seal ring for damage and interference with the retainer. Repair or replace the faulty parts. Then check the symptom.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Go to Step 9.
STEP 6. Check shift shock.
Q: Does shift shock occur?
YES: Go to Step 7.
NO: Go to Step 8.
STEP 7. Using scan tool MB991502, check data list item 11: Throttle position sensor.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Set scan tool MB991502 to data reading mode for item 11: Throttle Position Sensor.
^ With the throttle valve in idle position, voltage should be between 535 and 735 mV.
^ With the throttle valve in full-open position, voltage should be between 4,500 and 5,500 mV.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES: Go to Step 8.
NO: Check the throttle position sensor. Then check the symptom.
STEP 8. 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.
Q: Is the repair possible and the symptom eliminated?
YES: Diagnosis is complete.
NO: Replace the valve body assembly. Then check the symptom. Go to Step 9.
STEP 9. Replace the PCM.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Start over at Step 1.