Code No. P0012: Variable Valve Timing Advance Abnormality


FUNCTION



  • If the vehicle equipped with 4B11-T/C engine continues the rough driving like competitive running (the running that constantly repeats the cycle of the full opened position of the accelerator pedal and the full closed position of the accelerator pedal.), the amount of carbon mixed into the engine oil tends to increase. This can possibly cause the timing chain to gradually elongate. To prevent this, the function or logic monitoring the amount of elongation of the timing chain is integrated into the engine-ECU. The details are shown in timing chain maintenance (Refer to GROUP 00 - Precautions before Service - Timing Chain Maintenance ).

TROUBLE JUDGMENT


Check Condition
  • Ignition switch is "ON" position.
Judgment Criterion
  • The learning value for the current phase angle of V.V.T. at the intake (most retard angle) side and the exhaust (most advanced angle) side is different from the initial phase angle of V.V.T. by more than the specified value.
FAIL-SAFE AND BACKUP FUNCTION
  • None

PROBABLE CAUSE



  • Timing chain elongated

DIAGNOSIS PROCEDURE

STEP 1. Timing chain elongation visual check
Timing chain elongation visual check (Refer to GROUP 11E - On-vehicle Service - Timing Chain Elongation Visual Check ).

Q. Is the check result normal?
Initialise the learning value for the elongation of the timing chain (Refer to GROUP 00 - Precautions before Service - Timing Chain Maintenance <4B11-Turbo> ).
Replace the timing chain and the oil pump chain. Then initialise the learning value for the elongation of the timing chain (Refer to GROUP 00 - Precautions before Service - Timing Chain Maintenance <4B11-Turbo> ).