DTC P2178:00 [L5]: Notes
WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
DETECTION CONDITION & POSSIBLE CAUSES
| DTC P2178:00 |
Fuel system too rich at off idle |
| DETECTION CONDITION |
- The PCM monitors short term fuel trim (SHRTFT), 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).
- The MIL illuminates if 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 PCM detects the above malfunction conditions during first drive cycle.
- FREEZE FRAME DATA is available
- The DTC is stored in the PCM memory.
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| POSSIBLE CAUSE |
- Erratic signal to PCM
- APP sensor signal malfunction
- ECT sensor signal malfunction
- MAF sensor signal malfunction
- TP sensor signal malfunction
- VSS signal malfunction
- A/F sensor malfunction
- A/F sensor deterioration
- A/F sensor heater malfunction
- Leakage exhaust system
- MAF sensor malfunction
- Purge system malfunction
- Purge solenoid valve improper operation
- Purge solenoid valve malfunction (stuck open)
- Purge solenoid hoses improper connection
- PCV valve malfunction
- EGR valve improper operation
- VTCS improper operation
- Fuel pump malfunction
- Pressure regulator (built-in fuel injection pump) malfunction
- Fuel pump unit malfunction
- Fuel leakage on fuel line from fuel distributor and fuel pump
- Fuel filter clogged or restricted
- Ignition system malfunction
- Ignition coil related wiring harness malfunction
- Variable valve timing control system improper operation
- Fuel injector malfunction
- PCM malfunction
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