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P1456

Evaporative Emission Control System Leak Detected Fuel Tank System.

  • Acura
  • Powertrain
  • Manufacturer code
  • Low severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
4
AreaAuxiliary emission controls
56
FaultThe specific fault in that area

What it means

On Acura (as on Honda), P1456 means the control unit has detected a leak in the evaporative emission system on the fuel tank side. During the leak test the system could not hold or build the expected vacuum or pressure, which points to a leak somewhere around the tank, filler neck, filler cap or the pipes and valves connected to the tank.

Symptoms

  • Malfunction indicator lamp on
  • Smell of fuel around the car, especially after parking
  • Fuel filler cap warning or loose-cap message on some models
  • Difficulty filling the tank, with the pump nozzle clicking off early
  • Usually no change in driveability
  • Possible failure at an emissions test

Possible causes

  • Fuel filler cap loose, missing, damaged or with a worn seallikely
  • Damaged or perished filler neck seal or corroded filler neckpossible
  • Cracked, split or disconnected evaporative vapour hoses or pipes near the tanklikely
  • Leaking fuel tank pressure sensor seal, tank sender flange seal or rollover valvepossible
  • Faulty vapour control or vent valve sticking open or leakingpossible
  • Charcoal canister cracked or leakingrare
  • Fuel tank pressure sensor fault giving an incorrect readingrare

How to diagnose

  1. Read the stored codes and freeze frame data, and note whether other evaporative codes are present
  2. Check the fuel filler cap is fitted, tightened correctly, undamaged and has an intact seal
  3. Inspect the filler neck, its seal and the visible vapour hoses and connectors for cracks, perishing or detachment
  4. Check the wiring and connectors of the tank pressure sensor and the vent and purge valves for damage or corrosion
  5. Use the scan tool's live data to compare the tank pressure sensor reading with expected values and check it responds sensibly
  6. Operate the vent and purge valves using the scan tool's bidirectional tests and check they open and close properly, following the model-specific procedure
  7. Smoke test the evaporative system to locate the leak, using the correct low pressure equipment
  8. Clear the code and complete the drive cycle, then confirm the monitor passes

How to fix

  • Replace the fuel filler cap with a correct one if it is damaged or the seal is worn
  • Replace the filler neck seal or repair or replace the filler neck if corroded or leaking
  • Replace cracked or disconnected vapour hoses, pipes or clips
  • Replace the leaking tank seal, rollover valve or pressure sensor as found
  • Replace a faulty vent or purge valve
  • Replace the charcoal canister if it is proven to be leaking

Can I keep driving?

Low severity

The car is safe to drive in the short term as this is an emissions fault. Book it in soon, though, as a fuel vapour leak can smell and may cause an emissions test failure.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

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