2006 Mazda MPV ESFACTORY OEM SERVICE PROCEDURE

DTC P0456: Notes

DTC P0456 [AJ] DETECTION CONDITION AND POSSIBLE CAUSES

DTC P0456 Evaporative emission control system leak detected (very small leak)
DETECTION CONDITION 
  • The PCM measures the pump load current (EVAP line pressure) when a specified period has passed after the EVAP system is sealed when monitoring conditions are met. If the load does not reach the reference load value, or the rate of load increase is lower than the specified value within a specified period, the PCM determines that the EVAP system has a very small leak.

    MONITORING CONDITION 

    • IG switch OFF
    • IAT. 5-35 °C {40-95 °F} 
    • Battery voltage: 11 V or above 
    • Atmospheric pressure: 72.2 kPa {542 mmHg, 21.3 inHg} or above 
    • Fuel tank level 15-85% 

Diagnostic support note 

  • This is an intermittent monitor (Evaporative system).
  • The MIL illuminates if the PCM detects the above malfunction 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 condition during the first drive cycle.
  • DIAGNOSTIC MONITORING TEST RESULTS is available
  • FREEZE FRAME DATA is available.
  • DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • Purge solenoid valve malfunction
  • EVAP system leak detection pump malfunction
  • Charcoal canister malfunction
  • Fuel cap malfunction
  • Fuel tank malfunction
  • Fuel pump unit poor seal
  • EVAP hose damaged or loose
  • EVAP pipe damaged
  • PCM malfunction
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.