Code No. P0101:
Air Flow Sensor Performance
DIAGNOSIS CONTENT
Air mass ratio is higher than threshold high
TROUBLE JUDGMENT
Check Conditions
- No active EGR and open intake air control flap
- After specified time periods following time when engine starting sequence is completed.
- Engine is at operating temperature and not overheated.
- Vehicle is not at high altitude.
- Fuel injection quantity not too large.
- Air flow sensor is normal.
- Average engine speed is within monitoring range.
- Boost pressure is below upper threshold.
Judgment Criterion
- The ratio between normalized and current air mass per hour is above a threshold.
DIAGNOSIS CONTENT
Air mass ratio is lower than threshold low
TROUBLE JUDGMENT
Check Conditions
- No active EGR and open intake air control flap
- After specified time periods following time when engine starting sequence is completed.
- Engine is at operating temperature and not overheated.
- Vehicle is not at high altitude.
- Fuel injection quantity not too large.
- Air flow sensor is normal.
- Average engine speed is within monitoring range.
- The boost pressure is above a lower threshold.
Judgment Criterion
- The ratio between normalized and current air mass per hour is below a threshold.
PROBABLE CAUSE
- Failed air flow sensor
- Failed air intake system
(Refer to Symptom Procedure - Air Flow Sensor System 
.)