P0172 - System Too Rich (Bank 1)
The adaptive fuel strategy continuously monitors the fuel delivery hardware. The test fails when the adaptive fuel tables reach a lean calibrated limit. Refer to Section 1 , Powertrain Control Software, Fuel Trim for more information.
- Fuel Pressure Regulator (vacuum hose off, diaphragm leak, malfunctioning).
- Leaking fuel injectors.
- Fuel return line restricted.
- Fuel rail pressure sensor (incorrect reading).
- EVAP canister purge valve leak (when canister is full).
- Engine oil contamination.
Air Measurement System.
- MAF sensor (contaminated, damaged, or corroded connector).
View Freeze Frame Data to determine the operating conditions when the DTC was set. Observe the LONGFT1 and LONGFT2 PID(s). Refer to Section 2 , Adaptive Fuel DTCs Diagnostic Techniques for more information.