Inspection Procedure 7: N → R time lag


COMMENTS ON TROUBLE SYMPTOM



PROBABLE CAUSES



  • Insufficient A/T fluid amount, immixing of water or unspecified A/T fluid
  • Malfunction of stop lamp switch system
  • Malfunction of solenoid valve harness system
  • Malfunction of valve body
  • Malfunction of the A/T-ECU
  • A/T internal error (oil pump, clutch C3, brake B1/B4, one-way clutch F1, etc.)

DIAGNOSIS PROCEDURE

STEP 1. A/T fluid check
Check the A/T fluid for amount and condition (not severely contaminated), and fill or replace the A/T fluid if necessary. Then, check the trouble symptom again.

Q. Is the trouble symptom reproduced?
Go to Step 2.
This diagnosis is complete.

STEP 2. Hydraulic pressure test
Measure the line pressure (Refer to ).
note If a time lag occurs, the line pressure may be lower than the standard value.
OK: Refer to .

Q. Is the check result normal?
Go to Step 3.
Go to Step 4.

STEP 3. Stop lamp switch system check
The stop lamps should illuminate when the brake pedal is depressed, and extinguish when released.

Q. Is the check result normal?
Go to Step 6.
Refer to stop lamp switch system ().

STEP 4. Retest the system
If the trouble symptom occurs again, check and replace the solenoid harness. Then, check the trouble symptom again.

Q. Is the trouble symptom reproduced?
Go to Step 5.
This diagnosis is complete.

STEP 5. Retest the system
If the trouble symptom is not solved, replace the valve body. Then, check the trouble symptom again.

Q. Is the trouble symptom reproduced?
Go to Step 6.
This diagnosis is complete.

STEP 6. A/T-ECU replacement
(1)Replace the A/T-ECU.
(2)Test drive the vehicle.
(3)Verify that the condition described by the customer exists.

Q. Is the trouble symptom reproduced?
After checking the oil pump for damage, check each clutch and brake for any damage, and replace if necessary. (It is highly possible that the clutch C3, brake B1/B4, and one-way clutch F1 that engage in reverse gear are damaged.)
This diagnosis is complete.