Inspection Procedure 6: Hunting (Repeated Acceleration and Deceleration) Occurs at the Set Vehicle Speed.


COMMENTS ON TROUBLE SYMPTOM




note When the vehicle is driven with the low-speed gear in the sport mode, hunting occurs easily, however, this is not a failure.<A/T>

PROBABLE CAUSES



  • Malfunction of CAN bus system.
  • Malfunction of the diesel fuel system.
  • Malfunction of the A/T system. <A/T>
  • Malfunction of combination meter system.
  • Malfunction of the engine-ECU.

DIAGNOSIS PROCEDURE
caution
  • If there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Before replacing the ECU, ensure that the CAN bus lines is normal.

STEP 1. Check the CAN bus system diagnosis.
Using M.U.T.-III, perform CAN bus diagnosis (Refer to GROUP 54D - Explanation About The M.U.T-III Can Bus Diagnostics .)

Q. Is the check result satisfactory?
Go to Step 2.
Repair the CAN bus lines (Refer to GROUP 54D - Troubleshooting, Can Bus diagnosis Table .) Then go to Step 8.

STEP 2. Check the diesel fuel system diagnosis code.
Using M.U.T.-III, perform diesel fuel system diagnosis code (Refer to GROUP 13B - Troubleshooting, Diagnosis Function .)

Q. Is any diagnosis code set?
Repair the diesel fuel system (Refer to GROUP 13B - Troubleshooting, Inspection Chart for Diagnosis Code .) Then go to Step 8.
Go to Step 4. <M/T>
Go to Step 3. <A/T>

STEP 3. Check the A/T system diagnosis code. <A/T>
Using M.U.T.-III, perform A/T system diagnosis code (Refer to GROUP 23C - Troubleshooting, Diagnosis Function .)

Q. Is any diagnosis code set?
Repair the A/T system (Refer to GROUP 23C - Troubleshooting, Diagnosis Code Chart .) Then go to Step 8.
Go to Step 4.

STEP 4. Check the combination meter system diagnosis code.
Using M.U.T.-III, perform combination meter system diagnosis code (Refer to GROUP 54A - Combination meter, Troubleshooting, Diagnosis Function .)

Q. Is any diagnosis code set?
Repair the combination meter system (Refer to GROUP 54A - Combination meter, Troubleshooting, Diagnosis Code Chart .) Then go to Step 8 .
Go to Step 5.

STEP 5. Check the combination meter system data list.
Using M.U.T.-III, check the combination meter system data list (Refer to GROUP 54A - Combination meter, Troubleshooting, Data List Reference Table .)

  • Item 1: Speed meter
  • Item 2: Speed sensor confirmation flag
  • Item 3: Speed sensor failure flag

Q. Is the check result normal?
Go to Step 6.
Check the combination meter system {Refer to GROUP 54A - Combination meter, Troubleshooting, Symptom Procedures, Inspection Procedure 2: Speedometer does not Work (Other Meters Work) .] Then go to Step 8.

STEP 6. Check the data list.
Using M.U.T.-III, check the data list (Refer to - data list reference table.)

  • Item 04: Vehicle speed signal.

Q. Is the check result normal?
Go to Step 7.
Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU .) Then go to Step 8.

STEP 7. Check the symptom.

Q. Does a hunting occur?
Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU .) Then go to Step 8.
It can be assumed that this malfunction is intermittent (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, How to Cope with Intermittent Malfunctions .)

STEP 8. Check the symptom.

Q. Does a hunting occur?
Return to Step 1.
The procedure is complete.