Inspection Procedure 6
INSPECTION PROCEDURE 6: Shift shocks when shining from "N" to "D" and long delayCOMMENT
If abnormal shocks 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)
CAUTION: To prevent damage to the scan tool MB991502, always turn the ignition switch to "LOCK" (OFF) position before connecting or disconnecting the scan tool MB991502.
STEP 1. Using scan tool MB991502, carry out the actuator test.
1) Connect scan tool MB991502 to the data link connector.
2) Check the following item in the actuator test. Refer to Actuator Test Reference Table. a. Item 2: Underdrive solenoid valve
3) Check that the solenoid valve clicks.
Q: Does the solenoid click?
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 shocks occur.
Q: When the shift shocks 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).
1) 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 compressed air into the underdrive clutch oil orifice of the transmission 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 transmission 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 shocks.
Q: Do shift shocks 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.
1) Set scan tool MB991502 to the data reading mode for item 11, Throttle position sensor.
2) When the accelerator pedal is not depressed (throttle valve is fully closed), the display should be "535 to 735 mV."
3) When the accelerator pedal is depressed, the display should gradually rise.
4) When the accelerator pedal is fully depressed (throttle valve is fully open) (up to two seconds), the display should be "4,500 to 5,500 mV."
Q: Is the result of the above check good (Is throttle position sensor operating properly)?
YES: Go to Step 8.
NO: Check the throttle position sensor. Refer to diagnostic trouble code number 11, 12, 14 - Throttle Position Sensor System. Then check the symptom.
STEP 8. Disassemble and clean the valve body.
1) 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.
1) Replace the PCM. The immobilizer-ECU and the ignition key should be replaced together with it. Confirm that the malfunction symptom is eliminated.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Start over at Step 1.