Inspection Procedure 11: The Feeling of Impact or Vibration when Accelerating


  • Failure is possibly caused by ignition leak occurring in association with the increase of required voltage by the spark plug at an acceleration and failed electronic-control throttle valve system, and so on.


  • Failed ignition system
  • Failed electronic control throttle valve system
  • Contamination around the throttle valve
  • Failed CVT <CVT>
  • Failed engine-ECU


note To protect the CVT, the CVT-ECU outputs, into the engine-ECU, the request signal to reduce the engine torque according to the operation condition, Based on the signal, the engine-ECU closes the throttle valve, retards the ignition or carries out fuel cut. At that time, the engine output seems to temporarily reduce, but there is no malfunction.

STEP 1. M.U.T.-III diagnosis code

Q. Is diagnosis code set?

Inspection chart for diagnosis code (Refer to ).
Go to Step 3 <M/T>. Go to Step 2 <CVT>.

STEP 2. M.U.T.-III diagnosis code

note When the CVT has a malfunction, the CVT-ECU might output the request signal of reducing the engine torque in order to protect the CVT.

  • Confirm whether the diagnosis codes are output from CVT-ECU.

Q. Is the diagnosis code for the CVT system set?

Check for CVT System (Refer to GROUP 23A - Troubleshooting - Diagnosis Code Chart ).
Go to Step 3 .

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

  • Refer to Data List Reference Table .

  1. Item 11: Accelerator pedal position sensor (main)
  2. Item 12: Accelerator pedal position sensor (sub)
  3. Item 13: Throttle position sensor (main)
  4. Item 15: Throttle position sensor (sub)

Q. Are the check results normal?

Go to Step 4 .
Perform the diagnosis code classified check procedure for the sensor that has shown an abnormal data value (Refer to Inspection Chart for Diagnosis Code ).

STEP 4. Check throttle body (throttle valve portion) contamination.

Q. Is the check result normal?

Go to Step 5 .
Clean throttle body (throttle valve portion) (Refer to Throttle Body (Throttle Valve Area) Cleaning ).

STEP 5. Visual check of ignition spark.

  • Remove the spark plug and install it to the ignition coil.
  • Connect the ignition coil connector.
  • Remove all injector connector.
  • At the engine start, check each spark plug produces a spark.

Q. Is the check result normal?

Check end.
Go to Step 6 .

STEP 6. Check spark plug.

  • Check spark plug (Refer to GROUP 16 - Ignition System - On-vehicle Service - Spark Plug Check and Cleaning ).

Q. Is the check result normal?

Check ignition circuit system (Refer to Inspection Procedure 22 ).
Replace the spark plug.