Skip to content
Skip to content

OBD-II Code

P1456

Severity

Not yet reviewed

Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.

Can you drive it

We cannot say

Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.

Indicative cost (USD)

$25–$400

From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.

$25 (gas cap or single hose) to $400 (FTP sensor plus vent valve).

P1456 on a Honda is an EVAP Fuel Tank Pressure (FTP) Sensor fault — a circuit or performance problem with the sensor that monitors fuel-tank pressure (typically mounted on top of the fuel-tank assembly or in the filler-neck area depending on platform).

How a shop works this

Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.

  1. Note every code that is set, not just this one.

    Codes that appear together usually narrow the cause faster than any one of them read alone.

  2. Read the freeze frame — the conditions the fault was recorded under.

    Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.

  3. Confirm the fault is current rather than history.

    Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.

  4. Then follow the diagnostic notes further down this page, in the order they are written.

    They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.

If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.

Common symptoms

  • Check engine light
Read the full diagnostic procedureP1456 on a Honda is an EVAP Fuel Tank Pressure (FTP) Sensor fault — a circuit or performance problem with the sensor that monitors fuel-tank pressure…

P1456 on a Honda is an EVAP Fuel Tank Pressure (FTP) Sensor fault — a circuit or performance problem with the sensor that monitors fuel-tank pressure (typically mounted on top of the fuel-tank assembly or in the filler-neck area depending on platform). The FTP sensor outputs a 0.5-4.5V signal scaled to roughly -7 to +1 inH2O of tank pressure/vacuum — at static rest with a sealed tank, the FTP should sit near 2.5V (~0 inH2O); during an EVAP leak test, the canister vent solenoid closes and the purge valve cracks open to pull vacuum, dropping FTP to ~1.0-1.5V (~-3 to -5 inH2O) for the test duration, then the system seals and watches FTP rise back to ambient over a calibrated decay time. P1456 sets when the FTP doesn't reach the expected vacuum target, or rises back too fast (leak), or reads outside the plausible voltage window.

Cheapest-first ladder

  1. tighten the gas cap and drive 2-3 cold-start cycles (Honda EVAP monitors are notoriously slow to re-run, sometimes requiring 4-6 cold starts under 50-80F ambient with the tank between 1/4 and 3/4 full).
  2. Then inspect the FTP sensor connector for moisture (the sensor often sits on top of the fuel tank under the rear seat or in the filler neck area, which is a wet location).
  3. Smoke-test the EVAP system through the service port to find leaks.
  4. Backprobe the FTP signal wire and confirm ~2.5V at rest, scaling correctly during a commanded purge.
  5. Don't replace the fuel tank or sending unit on P1456 — the FTP sensor is usually a separate $50-90 part, and Honda dealers occasionally upsell the full tank assembly when the sensor alone is the failure.
Vehicle-specific patterns1998-2002 Accord 2.3L (F23) and 2001-2005 Civic 1.7L (D17) are the textbook P1456 platforms — Honda issued multiple TSBs (including a well-known one…
  • 1998-2002Accord 2.3L (F23) and 2001-2005 Civic 1.7L (D17) are the textbook P1456 platforms — Honda issued multiple TSBs (including a well-known one covering gas-cap replacement and an updated FTP sensor with a redesigned o-ring) for these platforms; the gas-cap-only fix clears P1456 on a non-trivial percentage of cases.
  • 2002-2006CR-V 2.4L (K24A1) throws P1456 from FTP-sensor connector corrosion under the rear cargo area where the harness passes through a body grommet.
  • 2003-2007Accord 2.4L / 3.0L V6 (K24/J30) throws P1456 from a cracked EVAP hose between the tank and the charcoal canister near the rear axle.
  • 2005-2010Odyssey 3.5L (J35) and Pilot 3.5L (J35) throws P1456 from a failed vent shut-off valve at the canister assembly — Honda part is $70-110.
  • 2006-2011Civic 1.8L (R18) throws P1456 less often, usually from the same gas-cap-seal failure mode as the older Civic.

Estimated repair$25 (gas cap or single hose) to $400 (FTP sensor plus vent valve).

Look up another code

More free tools

VIN DecoderDecode year, make, model, engine, recalls.Maintenance ScheduleOil, timing belt, fluids, by vehicle.Tire SizeOEM vs new — diameter delta + speedo error.Gas CostWeekly, monthly, annual fuel math.

See all 9 tools