[23A] AUTOMATIC TRANSMISSION (FF) - - TROUBLESHOOTING <A/T> - SYMPTOM PROCEDURES - Inspection Procedure 4: Does not Move BackwardPRINT PAGE / INDEX / PRIOR / NEXT
Inspection Procedure 4: Does not Move Backward
COMMENTS ON TROUBLE SYMPTOM
If the vehicle does not move backward when the selector lever is shifted to R range while the engine is idling, the cause is probably abnormal pressure of the reverse clutch and low-reverse brake or a malfunction of the reverse clutch, low-reverse brake, or valve body.
PROBABLE CAUSES
  • Abnormal reverse clutch pressure
  • Abnormal low-reverse brake pressure
  • Malfunction of low-reverse solenoid valve
  • Malfunction of the reverse clutch
  • Malfunction of low-reverse brake
  • Malfunction of valve body
  • Malfunction of the engine-A/T-ECU
DIAGNOSIS PROCEDURE
STEP 1. MUT-II/III actuator test
Item 01: Low-reverse solenoid valve
OK: Operating sound can be heard.
Q: Is the check result normal?
YES:  Go to Step 2.
NO:  Replace the low-reverse solenoid valve.
STEP 2. Hydraulic pressure test
Measure the hydraulic pressure for reverse clutch and low-reverse brake when the selector lever is at the R range (Refer to ).
OK: Refer to .
Q: Is the check result normal?
YES:  Go to Step 5.
NO:  Go to Step 3.
STEP 3. Engine-A/T-ECU replacement
  1. Replace the engine-A/T-ECU.
  1. Test drive the vehicle.
  1. Verify that the condition described by the customer exists.
Q: Does a malfunction take place again?
YES:  Go to Step 4.
NO:  The inspection is complete.
STEP 4. Valve body disassembly clean and assembly
  1. Check the bolts for looseness and the O-ring, solenoid valve and valve body for damage.
    Replace the valve body assembly if the damages are thought to be irreparable.
  1. Test drive the vehicle.
  1. Verify that the condition described by the customer exists.
Q: Does a malfunction take place again?
YES:  Go to Step 5.
NO:  The inspection is complete.
STEP 5. Reverse clutch and low-reverse brake check
Check the facing for seizure and the piston seal ring for damage and interference with the retainer.
Q: Is the check result normal?
YES:  The inspection is complete.
NO:  Repair or replace the reverse clutch and low-reverse brake.
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