Inspection Procedure 22: Shock is significant at shifting from N to D

COMMENTS ON TROUBLE SYMPTOM

If a strong shock occurs when the selector lever is shifted from N to D, the cause is probably an immixing of A/T fluid other than the specified one, a malfunction of the C1 pressure control solenoid (SL1) system, line pressure control solenoid (SLT) system, stop lamp switch system, mounting (engine mounting and transmission mounting insulator), input shaft speed sensor system, A/T fluid temperature sensor 1 system, or valve body.

note

As a cause of shock, an engine system malfunction, driveshaft malfunction (damage, wear, looseness, large deflection), or suspension malfunction (looseness) is suspected. However, in this item, it shall be presupposed that there is no abnormality to the above.

PROBABLE CAUSES

Malfunction of mounting (engine mounting and transmission mounting insulator)
Malfunction of input shaft speed sensor system
Malfunction of stop lamp switch system
Malfunction of A/T fluid temperature sensor 1 system
Immixing of A/T fluid other than the specified one
Malfunction of C1 pressure control solenoid (SL1) system
Malfunction of line pressure control solenoid (SLT) system
Malfunction of valve body (SL1, SLT)
Malfunction of the A/T-ECU
A/T internal error (clutch C1, one-way clutch F1, etc.)

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III actuator test

Item 4: Line pressure solenoid

Item 5: Linear solenoid 1

OK: Operating sound can be heard.

Q. Is the check result normal?

	Go to Step 2.

	Repair the C1 pressure control solenoid (SL1) system or line pressure control solenoid (SLT) system.

STEP 2. M.U.T.-III data list

Item 4: Input shaft speed sensor (Refer to data list reference table

Q. Is the check result normal?

	Go to Step 3.

	Repair the input shaft speed sensor system.

STEP 3. M.U.T.-III data list

Item 6: A/T fluid temperature sensor 1 (Refer to data list reference table

Q. Is the check result normal?

	Go to Step 4.

	Repair the A/T fluid temperature sensor 1 system.

STEP 4. Mounting check

Check the engine mounting and transmission mounting insulator for damage and any faults.

Q. Is the check result normal?

	Go to Step 5.

	Repair or replace the engine mounting and transmission mounting insulator.

STEP 5. 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 (Refer to GROUP 54A - ETACS - Troubleshooting, Input Signal Procedures ).

STEP 6. A/T fluid change

Replace the A/T fluid. Then, check the trouble symptom again.

Q. Is the trouble symptom reproduced?

	Go to Step 7.

	This diagnosis is complete.

STEP 7. Valve body replacement

Replace the valve body. Then, check the trouble symptom again.

Q. Is the trouble symptom reproduced?

	Go to Step 8.

	This diagnosis is complete.

STEP 8. A/T-ECU replacement

Replace the A/T-ECU. Then, check the trouble symptom again.

Q. Is the trouble symptom reproduced?

	Check the clutches and brakes for damage, and replace if necessary. (It is highly possible that the clutch C1 and one-way clutch F1 that engage in 1st gear are damaged.)

	This diagnosis is complete.