Dtc P2178 [Z6] - Mazda 3 Workshop Manual

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
• Perform the "PCM Adaptive Memory
Produce Drive Mode".
(See OBD DRIVE MODE
• Is the PENDING CODE for this DTC
present?
VERIFY AFTER REPAIR PROCEDURE
• Perform the "AFTER REPAIR
PROCEDURE".
18
(See AFTER REPAIR PROCEDURE
• Are any DTCs present?
DTC P2178
• The PCM monitors short term fuel trim (SHRTFT) and long term fuel trim (LONGFT)
during closed loop fuel control at off-idle. If the LONGFT or the sum total of these fuel
trims exceed preprogrammed criteria, PCM determines that fuel system is too rich at
off-idle.
Diagnostic support note
• This is a continuous monitor. (Fuel system)
• MIL illuminates if PCM detects the above malfunctioning condition in two
DETECTION
CONDITION
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.
• Misfire
• Front HO2S deterioration
• Front HO2S heater malfunction
• MAF sensor malfunction
• Pressure regulator (built-in fuel pump unit) malfunction
POSSIBLE
• Fuel pump malfunction
CAUSE
• EGR valve improper operation
• Variable tumble shutter valve actuator improper operation
• Purge solenoid valve improper operation
• Purge solenoid valve malfunction (stuck open)
Downloaded from
[Z6].)
Yes
[Z6].)
No DTC troubleshooting completed.

DTC P2178 [Z6]

System too rich off idle
https://carmanualshub.com/
Go to the applicable DTC inspection.
(See DTC TABLE [Z6].)
- automotive repair manuals website
B3E010202100W08