P0455 on a 2012 Honda Civic
EVAP Large or Gross Leak Detected
P0455 on a 2012 Honda Civic indicates evap large or gross leak detected. It usually stays drivable short-term but should be diagnosed promptly. The most common cause is missing, loose, or wrong-fit fuel cap (typically $0–$60). Confirm the root cause before replacing parts.
What does P0455 mean on a 2012 Honda Civic?
P0455 is set when the EVAP system's gross-leak monitor detects an opening approximately 0.090 inches (2.3 mm) or larger — or in many cases, no seal at all. This is the size of a missing gas cap, a disconnected hose, or a failed vent solenoid stuck open. The system cannot hold pressure or vacuum for the calibration period, so the ECM concludes a major leak.
This guide covers P0455 across the 2010-2014 Honda Civic generation — the symptoms, causes, and diagnostic steps below apply to every model year from 2010 through 2014.
Is it safe to drive a 2012 Honda Civic with P0455?
In most cases a 2012 Honda Civic stays drivable for short trips with P0455 active, but diagnose and repair it promptly. This is a low-severity code — ignoring it can lead to further damage or a failed emissions test.
What are the symptoms of P0455 on a 2012 Honda Civic?
- Check Engine Light is illuminated
- Distinct fuel smell, especially after refueling
- Fuel-cap warning message on the dashboard on some vehicles
- No drivability issue
- Vehicle will fail emissions / smog testing
What causes P0455 on a 2012 Honda Civic?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Missing, loose, or wrong-fit fuel cap Always check first. A locking gas cap from another vehicle that almost fits is a common source. | Most common | $0–$60 |
| Disconnected or split EVAP hose | Common | $30–$200 |
| EVAP vent valve stuck open (will not seal during the monitor test) | Common | $80–$350 |
| Damaged or rusted-through fuel filler neck | Occasional | $200–$700 |
| Cracked or broken EVAP charcoal canister | Occasional | $200–$600 |
| Damaged O-ring at the fuel pump assembly cover | Rare | $30–$500 |
| Rodent damage to EVAP hoses (parked vehicles) | Occasional | $30–$200 |
How to diagnose this on a 2012 Honda Civic
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Check the gas cap is present and correctly seated
Confirm the cap is the correct OEM cap for the vehicle. Many generic-fit replacement caps look identical but have slightly wrong gasket geometry. Hand-tighten to at least 3 clicks. Some vehicles flag a missing cap as P0455 within one drive cycle.
Tools: None
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Visually inspect the EVAP hoses near the canister
On most trucks and SUVs the EVAP canister sits behind the rear bumper or above the rear axle. Inspect every hose from the canister to the tank vent and to the purge solenoid. Pay particular attention to rodent damage on parked vehicles.
Tools: Floor jack and stands, Flashlight
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Smoke-test the EVAP system at low pressure
Introduce smoke at 0.5 psi through the service port. With a large leak the smoke will pour visibly from the failure point within seconds. If smoke escapes from the vent solenoid even with the solenoid commanded closed, replace the solenoid.
Tools: EVAP smoke machine
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Test the EVAP vent valve function
Disconnect the vent valve and apply 12 V — it should click and close. Hold a hand vacuum pump to one port and verify the valve holds vacuum when energized. A vent valve that does not close fully will set P0455 because the system can never seal.
Tools: 12 V test source, Hand vacuum pump
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Inspect the fuel filler neck and tank-top seals
Rust-belt vehicles often develop pinholes or seam separation in the metal portion of the fuel filler neck. Once the rust is through, the EVAP system cannot hold any vacuum. Replacement is the only fix.
Tools: Floor jack and stands, Inspection mirror
NHTSA complaints & recalls for the 2012 Honda Civic
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2012 Honda Civic. Use these to gauge how common a problem is on your specific vehicle before you start chasing Honda Civic diagnostics.
- POWER TRAIN 49
- VEHICLE SPEED CONTROL 38
- AIR BAGS 147
- STEERING 74
- ELECTRICAL SYSTEM 59
3 active recalls
- STEERING:COLUMN Nov 2012
Honda is recalling certain model year 2012 Civic passenger vehicles, manufactured from October 26, 2012, through October 30, 2012. These vehicles were assembled with the incorrect steering column assembly.…
NHTSA campaign 12V548000 - FUEL SYSTEM, OTHER:DELIVERY:HOSES, LINES/PIPING, AND FITTINGS May 2011
HONDA IS RECALLING CERTAIN MODEL YEAR 2012 CIVIC 2-DOOR AND 4-DOOR VEHICLES MANUFACTURED FROM APRIL 21, 2011, THROUGH MAY 2, 2011. THERE IS A POSSIBILITY THAT AN O-RING, WHICH SEALS A CONNECTION IN THE FUEL FEED LINE, IS MISALIGNED. IF THE O-RING IS MISALIGNED, A SMALL FUEL LEA…
NHTSA campaign 11V288000 - POWER TRAIN:DRIVELINE:DRIVESHAFT Jun 2012
HONDA IS RECALLING CERTAIN MODEL YEAR 2012 HONDA CIVIC VEHICLES. DURING ASSEMBLY, THE PROCESS REQUIRED TO SEAT THE DRIVERS SIDE DRIVESHAFT AND SET THE RETAINING CLIP WAS NOT COMPLETED. AS A RESULT, THE DRIVESHAFT MAY SEPARATE.…
NHTSA campaign 12V256000
How do I fix P0455 on a 2012 Honda Civic?
- Replace the fuel cap
- Replace the EVAP vent valve / vent solenoid
- Replace damaged EVAP hoses
- Replace the EVAP charcoal canister
- Replace the fuel filler neck
About the 2010-2014 Honda Civic
The 2010-2014 Honda Civic was commonly sold with the following powertrains: 2.0L I4, 1.5L Turbo I4, 1.8L I4. Common trims include LX, Sport, EX, Touring.
How fast P0455 sets after a missing cap
Most OBD-II vehicles flag P0455 within one cold-start drive cycle after the cap is left off. Some Ford and GM vehicles will set a more specific “check fuel cap” message first and only escalate to P0455 if the issue persists across multiple drive cycles.
P0455 right after winter on a parked vehicle
Mice and rats chew EVAP hoses to nest inside the canister or near the fuel tank. If P0455 appears on a vehicle that has been parked for the winter, inspect every accessible EVAP hose for clean-edged bite marks before buying parts. This pattern is so common on rural-parked trucks that several shop forums have dedicated threads.
The cap that “fits” but doesn’t seal
A locking gas cap from a similar-vintage vehicle in the same brand family often threads on but seals against the filler neck at the wrong depth or angle. The result is repeated P0455 codes after every refuel. If the cap has been replaced and the code persists, double-check it is the exact OEM part number for this vehicle.
P0455 on a 2012 Honda Civic: frequently asked questions
What does diagnostic trouble code P0455 mean on a 2012 Honda Civic?
P0455 is set when the EVAP system's gross-leak monitor detects an opening approximately 0.090 inches (2.3 mm) or larger — or in many cases, no seal at all. This is the size of a missing gas cap, a disconnected hose, or a failed vent solenoid stuck open. The system cannot hold pressure or vacuum for the calibration period, so the ECM concludes a major leak.
What are the symptoms of P0455 on a 2012 Honda Civic?
Check Engine Light is illuminated. Distinct fuel smell, especially after refueling. Fuel-cap warning message on the dashboard on some vehicles. No drivability issue. Vehicle will fail emissions / smog testing
What causes P0455 on a 2012 Honda Civic?
Missing, loose, or wrong-fit fuel cap (most-common). Disconnected or split EVAP hose (common). EVAP vent valve stuck open (will not seal during the monitor test) (common). Damaged or rusted-through fuel filler neck (occasional). Cracked or broken EVAP charcoal canister (occasional). Damaged O-ring at the fuel pump assembly cover (rare). Rodent damage to EVAP hoses (parked vehicles) (occasional)
Is it safe to drive a 2012 Honda Civic with P0455?
In most cases a 2012 Honda Civic stays drivable for short trips with P0455 active, but it should be diagnosed and repaired promptly — this is a low-severity code. Ignoring it can lead to further damage or a failed emissions test.