DTC P0171-00: System Too Lean Bank 1; DTC P0172-00: System Too Rich Bank 1; DTC P1170-00: Fuel Performance/Port Injector; DTC P117B-00: Fuel Performance/Direct Injector [12/2019 - 10/2022]: Description
The fuel trim is related to the feedback compensation value, not to the basic injection duration. The fuel trim consists of both the short-term and long-term fuel trims.
The short-term fuel trim is fuel compensation that is used to constantly maintain the air fuel ratio at stoichiometric levels. The signal from the air fuel ratio sensor (sensor 1) indicates whether the air fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air fuel ratio is rich and an increase in the fuel injection volume if lean.
Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to vary from the central value. The long-term fuel trim, which controls overall fuel compensation, compensates for long-term deviations in the fuel trim from the central value caused by the short-term fuel trim compensation.
| DTC No. | Detection Item | DTC Detection Condition | Trouble Area | MIL | Memory | Note |
|---|---|---|---|---|---|---|
| P0171-00 | System Too Lean Bank 1 | With a warm engine and stable air fuel ratio feedback, the fuel trim is considerably in error to the lean side (2 trip detection logic). |
|
Comes on | DTC stored | SAE Code: P0171 |
| P0172-00 | System Too Rich Bank 1 | With a warm engine and stable air fuel ratio feedback, the fuel trim is considerably in error to the rich side (2 trip detection logic). |
|
Comes on | DTC stored | SAE Code: P0172 |
| P1170-00 | Fuel Performance/Port Injector | Although a DTC is stored for a rich or lean condition, the amount of fuel trim during direct injection is normal (1 trip detection logic) |
|
Does not come on | DTC stored | SAE Code: P1170 |
| P117B-00 | Fuel Performance/Direct Injector | Although a DTC is stored for a rich or lean condition, the amount of fuel trim during port injection is normal (1 trip detection logic) |
|
Does not come on | DTC stored | SAE Code: P117B |
HINT:
- When DTC P0171-00 is stored, the actual air fuel ratio is on the lean side. When DTC P0172-00 is stored, the actual air fuel ratio is on the rich side.
- If the vehicle runs out of fuel, the air fuel ratio is lean and DTC P0171-00 may be stored. The MIL is then illuminated.
- When DTC P1170-00 or P117B-00 is output, it may not be possible to precisely determine whether the port injection or the direct injection is malfunctioning, depending on the conditions. In this case, perform an Active Test (Control the Injection Mode) to determine which injection system is malfunctioning.