Inspection Procedure 6
COMMENTIf abnormal shocks or delay of two seconds or more occurs when the selector lever is shifted from "N" to "13" 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
DIAGNOSIS
Required Special Tool: MB991502: Scan Tool (MUT-II)
CAUTION: To prevent damage to scan tool MB991502, make sure the ignition switch is "OFF" before connecting or disconnecting scan tool MB991502.
STEP 1. Using scan tool MB991502, carry out the actuator test.
1. Check the following item in the actuator test. Refer to Actuator Test Reference Table. Actuator Test Reference Table
a. Item 2: Underdrive solenoid valve
2. Check that the solenoid valve clicks.
If the solenoid clicks, go to Step 2.
If the clicks cannot be heard, repair or replace the underdrive solenoid. Refer to Valve Body. Then confirm that the symptom is eliminated.
STEP 2. Check when shift shocks occur.
If shift shocks occur when engaging from "N" to "D", go to Step 3.
If shift shocks occur 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. Refer to Hydraulic Pressure Test. Component Tests and General Diagnostics
If within the standard value, go to Step 4.
If not within the standard value, 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.
If air pressure is not maintained, go to Step 5.
If air pressure is maintained, go to Step 8.
STEP 5. Check the underdrive clutch.
Remove the transmission assembly.
Check the facing for seizure and the piston seal ring for damage and interference with the retainer. Repair or replace the faulty parts. Refer to Underdrive Clutch. Then check the symptom.
If the symptom is eliminated, diagnosis is complete.
STEP 6. Do shift shocks occur?
If yes, go to Step 7.
If no, go to Step 8.
Required Special Tool: MB991502: Scan Tool (MUT-II)
CAUTION: To prevent damage to scan tool MB991502, make sure the ignition switch is "OFF" before connecting or disconnecting scan tool MB991502.
STEP 7. Using scan tool MB991502, check data list item 11: Throttle position sensor.
1. When the accelerator pedal is not depressed (throttle valve is fully closed), the display should be "300 to 1,000 mV"
2. When the accelerator pedal is depressed, the display should gradually rise.
3. When the accelerator pedal is fully depressed (throttle valve is fully open) (up to two seconds), the display should be "4,500 to 5,000 mV"
If the result of the above check is not good (throttle position sensor is not operating properly), check the throttle position sensor. Refer to diagnostic trouble code number 11, 12, 14 - Throttle Position Sensor System. Then check the symptom. DTC 11
If the result of the above check is good (throttle position sensor is operating properly), go to Step 8.
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. Refer to Valve Body.
If repair is not possible, replace the valve body assembly. Then check the symptom.
If the symptom is eliminated, diagnosis is complete.