P0172 System too Rich (bank 1)

P0172 System too Rich (bank 1)

Fuel Trim Circuit

Check Conditions
Under the closed loop air/fuel ratio control. Engine coolant temperature is higher than 77°C (171°F). Volume airflow sensor output frequency is 100 Hz or more.
Judgment Criteria
Long-term fuel trim has continued to be lower than −12.5 percent for 5 seconds
or Short-term fuel trim has continued to be lower than −7.4 percent for 5 seconds.
Check Conditions
Under the closed loop air/fuel ratio control. Engine coolant temperature is higher than 77°C (171°F). Volume airflow sensor output frequency is 100 Hz or less.
Judgment Criteria
Long-term fuel trim has continued to be lower than −12.5 percent for 5 seconds.
or Short-term fuel trim has continued to be lower than −12.5 percent for 5 seconds.
Check Conditions
Engine coolant temperature is higher than 77°C (171°F). Under the closed loop air/fuel ratio control.
Judgment Criteria
Long-term fuel trim has continued to be −12.5 percent for 5 seconds or Short-term fuel trim has continued to be −30.0 percent for 5 seconds.

The most likely causes for this code to be set are:
- Volume airflow sensor failed.
- Injector (Number 1, 3, 5) failed.
- Incorrect fuel pressure.
- Air drawn in from gaps in gasket, seals, etc.
- Right bank heated oxygen sensor failed.
- Engine coolant temperature sensor failed.
- Intake air temperature sensor failed.
- Barometric pressure sensor failed.
- Exhaust leak.
- Use of incorrect or contaminated fuel.
- PCM failed.