Inspection Procedure 7
INSPECTION PROCEDURE 7: Shift Shock when Shifting from "N" to "R" and Long DelayCOMMENT
If abnormal shocks or delay of two seconds or more occurs when the selector lever is shifted from "N" to "R" range while the engine is idling, the cause is probably abnormal reverse clutch pressure or low reverse brake pressure, or a malfunction of the reverse clutch, low-reverse brake, valve body or throttle position sensor.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set:)
- Abnormal reverse clutch pressure
- Abnormal low-reverse brake pressure
- Malfunction of the low-reverse solenoid valve
- Malfunction of the reverse clutch
- Malfunction of the low-reverse brake
- 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 01: Low-Reverse 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 the "ON" position.
3. Set scan tool MB991502 to actuator test mode for item 01: Low-Reverse 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 low-reverse solenoid valve. Then confirm that the symptom is eliminated.
STEP 2. Check when shift shock occurs.
Q: When does the shift shock occurs?
When engaging from N to R: Go to Step 3.
When the vehicle starts moving: Go to Step 7.
STEP 3. Check the hydraulic pressure (for reverse clutch).
Measure the hydraulic pressure for reverse clutch when the selector lever is at the "R" range. Check if the hydraulic pressure is within the standard value. Refer to, Hydraulic Pressure Test.
Q: Is the hydraulic pressure within the standard value?
YES: Go to Step 4.
NO: Go to Step 9.
STEP 4. Check the hydraulic pressure (for low-reverse, brake).
Measure the hydraulic pressure for low-reverse brake when the selector lever is at the "R" range. Check if the hydraulic pressure is within the standard value. Refer to, Hydraulic Pressure Test.
Q: Is the hydraulic pressure within the standard value?
YES: Go to Step 5.
NO: Go to Step 9.
STEP 5. Check the reverse clutch system and low-reverse brake system.
1. Remove the valve body cover and valve body.
2. Blow 108 kPa (15 psi) compressed air into the reverse clutch oil orifice of the transaxle case, and check if the reverse clutch piston moves and air pressures are maintained in that condition. Repeat for the low-reverse brake.
Q: Are both air pressures maintained?
YES: Go to Step 6.
NO: Go to Step 9.
STEP 6. Check the reverse clutch and low-reverse brake.
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 for the symptom.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Go to Step 10.
STEP 7. Check shift shock.
Q: Dose shift shock occur sometimes?
YES: Go to Step 8.
NO: Go to Step 9.
STEP 8. Using scan tool M8991502, 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 the "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 9.
NO: Check the throttle position sensor. Refer to diagnostic trouble code number 11, 12, 14: Throttle Position Sensor System. Then check the symptom.
STEP 9. 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 10.
STEP 10. Replace the PCM.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Start over at Step 1.