DTC P2178: Notes
DTC P2178 DETECTION CONDITION AND POSSIBLE CAUSES
| DTC P2178 |
Fuel system too rich at off idle |
| DETECTION CONDITION |
- PCM monitors the short term fuel trim (SHRTFT) and long term fuel trim (LONGFT) during closed loop fuel control at off-idle. If the LONGFT and the sum total of these fuel trims exceed the preprogrammed criteria, the PCM determines that fuel system is too rich at off-idle.
Diagnostic support note
- This is a continuous monitor. (Fuel system)
- MIL illuminates if the PCM detects the above malfunctioning condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
- PENDING CODE is available if the PCM detects the above malfunction conditions during the first drive cycle.
- FREEZE FRAME DATA is available.
- DTCs are stored in the PCM memory.
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| POSSIBLE CAUSE |
- Misfire
- Front HO2S deterioration
- Front HO2S heater malfunction
- MAF sensor malfunction
- Pressure regulator malfunction
- Fuel pressure sensor malfunction
- Relief valve (built-in fuel delivery pipe) malfunction
- Spill valve control solenoid valve (built-in high pressure fuel pump) malfunction
- High pressure fuel pump malfunction
- Fuel pump malfunction
- EGR valve improper operation
- Variable swirl control improper operation
- Purge solenoid valve improper operation
- Purge solenoid valve malfunction (stuck open)
- Purge solenoid hoses improper connection
- PCV valve malfunction
- Variable valve timing control system improper operation
- PCM malfunction
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