1. If small injection quantity learning has not been executed, the engine warning lamp blinks.
  2. When the requirements for learning are satisfied by operation after replacement of the engine-ECU, learning is automatically executed even if no instruction is given from the M.U.T.-III. Accordingly, the malfunction indicator lamp goes off. However, the learning thus executed is tentative and limited. Be sure to complete leaning using the M.U.T.-III.


To keep emission and noise level at adequate levels, the engine-ECU must learn injector fuel injection in idle mode.
During learning, the engine-ECU calculates actual injection from each cylinder based on changes in engine speeds and corrects pilot injection control. It then keeps records of this amount of correction as a learned value.
For this reason, after the engine-ECU or injector is replaced, learning must be executed using the M.U.T.-III.
note Engine friction changes or injector deterioration over time may cause fluctuation in pilot injection. After use over time, it may prevent injection of an accurate amount of fuel according to the indication by the engine-ECU. This is why learning must be executed again periodically.
For this reason, the engine-ECU periodically leans injection according to the cumulative mileage.
Note that making the M.U.T.-III learn again resets the cumulative mileage.
note The engine sound may change or idling engine speeds may increase during injection learning. These are not abnormalities.


caution To prevent damage to M.U.T.-III, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting M.U.T.-III.

1.After the ignition switch is in "LOCK" (OFF) position, connect the M.U.T.-III to the diagnosis connector.
2.Put the vehicle in the following idling stable conditions:

  • Engine coolant temperature: 76 - 100°C
  • Fuel temperature: 30 - 100°C
  • Intake air temperature: -30 to 100°C
  • Barometric pressure: 70 kPa or more
  • Lamps, radiator fan and all accessories: OFF
  • Transmission: Neutral
  • Power steering: Static state
3.Select "MPI/GDI/DIESEL" from System select Screen of the M.U.T.-III.
4.Select "Special Function" from MPI/GDI/DIESEL Screen.
5.Select "Learning" from Special Function Screen.
6.Select Item No. 1 "Small Injection qt. Learning" from the Learning Screen to execute learning.
    If the vehicle conditions go out of the learning conditions during idling, learning is interrupted.
    To reexecute learning, the ignition switch must once be turned off.
7.Continue idling for about 3 minutes before learning is completed.
8.Confirm that the engine warning lamp is off. If it still blinks, reexecute learning.