Inspection Procedure 4

INSPECTION PROCEDURE 4: Does not move (forward or backward)

COMMENT
- If the vehicle does not move forward or backward when the selector lever is shifted to any position while the engine is idling, the cause is probably abnormal line pressure, or a malfunction of the power train, oil pump or valve body

TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Abnormal line pressure
- Malfunction of the power train
- Malfunction of the oil pump
- Malfunction of the valve body
- Low A/T fluid level
- Malfunction of the PCM

DIAGNOSIS

STEP 1. Check the hydraulic pressure.
Measure the hydraulic pressure of each element when the transmission is in 1st, 2nd or reverse. Check if each hydraulic pressure is within the standard value. If some elements are within the standard value and some are not, recheck the symptom.
Q: Are all pressures within the standard value?
YES: Check A/T fluid level and condition. If not OK, repair or replace as necessary, then recheck symptom. If OK, go to Step 3.
NO: Go to Step 2.





STEP 2. Disassemble and clean the valve body.
Check the O-ring installation bolts for looseness and 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. If the symptom is not eliminated, go to Step 4.





STEP 3. Check the transmission power train components.
Disassemble the transmission and check the planetary carrier and output shaft, etc. Repair or replace the damaged parts. Then check the symptom.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Go to Step 5.





STEP 4. Replace the oil pump.
1. Remove the transmission.
2. Replace the oil pump (Oil pump cannot be repaired). Then check the symptom.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Go to Step 5.

STEP 5. Replace the PCM.
Q: Is the symptom eliminated?
YES: Diagnosis is complete.
NO: Start over at Step 1.