P1456: Honda: leak found in the EVAP control system on the fuel tank side
EVAP control system leakage (fuel tank system)
Severity: Monitor
Honda bulletins for this code describe a lit check engine light caused by a loose, binding or wrong fuel cap or an EVAP leak, with no drivability complaint.
P1456 in short
On Honda, P1456 means the computer found a leak in the EVAP system on the fuel tank side. Honda bulletins most often tie it to a loose, binding or wrong fuel cap, or to a leak found by an EVAP function test. It does not normally affect driving, but the leak should be found and fixed.
Honda runs a leak test on the evaporative system. P1456 is its code for a leak on the fuel tank side; P1457 is the matching code for the canister side.
Honda service bulletins say the cause on many 1997-2004 cars is the fuel cap: it can be loose, missing, the wrong cap, or bind on some CR-V, Insight, S2000 and Acura RL and NSX models. When the cap is fine, Honda has dealers run an EVAP function test to find the leak.
Owner complaints on 1998 Accords describe P1456 and P1457 together, with the canister and shut valve found at fault.
Pick your make
P1456 is a manufacturer-specific code: its meaning depends on who built the car.
Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.
Most likely causes
Cause 1: Fuel cap loose, missing, wrong or binding
Supported by vehicle data- Why it ranks here
- Honda bulletins 04-002 and 04001 describe a binding fuel fill cap setting P1456, and bulletin 608036 names a loose, missing or incorrect cap.
- What would change this
- Rises if the cap is loose or damaged or the light came on after refuelling. Falls if a new cap does not clear the code.
Cause 2: Leak in the tank-side EVAP hoses or fittings
Supported by vehicle data- Why it ranks here
- Honda bulletin SB-99-075 has dealers run the EVAP function test to find the leak behind P1456 or P1457, and B99-040 separates the tank-side test from the canister-side test.
- What would change this
- Rises if the EVAP function test or smoke test finds a leak. Falls if the system holds pressure.
Cause 3: EVAP canister or shut valve fault
Possible — needs testing- Why it ranks here
- An owner of a 1998 Accord reports P1456 and P1457 traced to the canister and shut valve. This is a single complaint, so it ranks below the bulletin causes.
- What would change this
- Rises if P1457 is stored too and the valve fails its test. Falls if the valve holds.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Check that the fuel cap is the correct one for the car, seated and clicking tight, with an undamaged seal. Replace it if it binds.
IfCap loose, damaged or binding
It meansReplace it, clear the code and drive.
IfCap is fine
It meansMove on to the leak test.
Step 2: Have the EVAP system function-tested or smoke-tested on the tank side, as Honda prescribes in SB-99-075.
Warning:EVAP testing uses a pressurised fuel system. Leave it to a shop.
IfA leak is found at a hose or fitting
It meansRepair that leak.
IfNo leak found but P1457 is stored too
It meansTest the canister and shut valve.
Symptoms
- Check engine light, car runs normally
- Light came on after getting gas
Compare with: Check engine light came on after getting gas
How to fix
Step 1: Check the fuel cap is the right one, clicks tight and is not binding; replace it if not.
Parts and cost context
- Fuel (gas) cap:A correct, undamaged cap is the first and cheapest thing Honda points to for this code.
Labor varies by vehicle and shop; get a quote before you approve a repair.
Compare used part prices on PartPriceGuideOn your vehicle
HondaYour car
1996–2006 · Accord
Supported by vehicle dataHonda bulletin SB-99-075 prescribes an EVAP function test for P1456 and P1457, and owner complaints on 1998 Accords report both codes.
2002–2004 · CR-V
Supported by vehicle dataHonda bulletin 04-002 says a binding fuel fill cap can set P1456 on the CR-V, Insight and S2000.
SB-99-075Status unverified
Troubleshooting DTC P1456 and P1457
1996–2006odyssey, s2000, insight, cr-v, civic, accord, pilot · NHTSA 10053545
Dealers run the EVAP function test to find the leak so it can be repaired.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
04-002Status unverified
Fuel fill cap binds, MIL with P1456
2002–2004cr-v, insight, s2000 · NHTSA 10011094
Fuel cap binding can set the MIL with P1456.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
010402Status unverified
Testing for internal leaks with P1456 or P1457
1998–2002s2000, accord, civic, cr-v, insight, odyssey, prelude · NHTSA 636753
Information on internal leak testing.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
P1456 questions
What does P1456 mean on a Honda?
Honda uses it for an EVAP leak on the fuel tank side. P1457 is the canister-side equivalent. Other makes may use P1456 differently, and this page only covers Honda.
Will a new gas cap fix P1456?
Often, on older Hondas. Honda bulletins cite loose, wrong or binding caps. If the code returns, an EVAP leak test is the next step.
Sources and review
- Honda and Acura service bulletins on DTC P1456 (EVAP control system leakage, fuel tank system)
- NHTSA complaint ODI 768976: 1998 Honda Accord, P1456 and P1457
- NHTSA complaint ODI 629548: 1998 Honda Accord, P0420, P0505, P1456
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error