Inspection Procedure 23: Shock is significant at shifting from N to R

COMMENTS ON TROUBLE SYMPTOM

If a strong shock occurs when the selector lever is shifted from N to R, the cause is probably an immixing of A/T fluid other than the specified one, a malfunction of the C3 pressure control solenoid (SL3) system, line pressure control solenoid (SLT) system, stop lamp switch system, mounting (engine mounting and transmission mounting insulator), 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 stop lamp switch system
Immixing of A/T fluid other than the specified one
Malfunction of C3 pressure control solenoid (SL3) system
Malfunction of line pressure control solenoid (SLT) system
Malfunction of valve body (SL3, SLT)
Malfunction of the A/T-ECU
A/T internal error (clutch C3, brake B2, etc.)

DIAGNOSIS PROCEDURE

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

Item 4: Line pressure solenoid

Item 7: Linear solenoid 3

OK: Operating sound can be heard.

Q. Is the check result normal?

	Go to Step 2.

	Repair the C3 pressure control solenoid (SL3) system or line pressure control solenoid (SLT) system.

STEP 2. Mounting check

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

Q. Is the check result normal?

	Go to Step 3.

	Repair or replace the engine mounting and transmission mounting insulator.

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 4.

	Refer to stop lamp switch system (Refer to GROUP 54A - ETACS - Troubleshooting, Input Signal Procedures ).

STEP 4. A/T fluid change

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

Q. Is the trouble symptom reproduced?

	Go to Step 5.

	This diagnosis is complete.

STEP 5. Valve body replacement

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

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 C3 and brake B2 that engage in reverse gear are damaged.)

	This diagnosis is complete.