DTC Detecting Condition and Trouble Area

DTC DETECTING CONDITION CHART

DTC detecting condition	Trouble area
DTC P0171 System Too Lean (Sensor-1, Bank-1): Total fuel trim (short term + long term fuel trim) is larger than 127% for more than 20 sec, or short term fuel trim is larger than 130% for more than 30 sec. (2 driving cycle detection logic) DTC P0172 System Too Rich (Sensor-1, Bank-1): Total fuel trim (short term + long term fuel trim) is smaller than 71% for more than 20 sec, or short term fuel trim is larger than 70% for more than 30 sec. (2 driving cycle detection logic)	Vacuum leakage Exhaust gas leakage Fuel pressure out of specification Fuel injector malfunction A/F sensor malfunction MAF sensor malfunction Intake & exhaust valve clearance Intake & exhaust valve Valve timing ECM

DTC detecting condition

Trouble area

DTC P0171 System Too Lean (Sensor-1, Bank-1):
Total fuel trim (short term + long term fuel trim) is larger than 127% for more than 20 sec, or short term fuel trim is larger than 130% for more than 30 sec.
(2 driving cycle detection logic)
DTC P0172 System Too Rich (Sensor-1, Bank-1):
Total fuel trim (short term + long term fuel trim) is smaller than 71% for more than 20 sec, or short term fuel trim is larger than 70% for more than 30 sec.
(2 driving cycle detection logic)

Vacuum leakage
Exhaust gas leakage
Fuel pressure out of specification
Fuel injector malfunction
A/F sensor malfunction
MAF sensor malfunction
Intake & exhaust valve clearance
Intake & exhaust valve
Valve timing
ECM